Effects of Doxycycline and Corticotomy on

Interleukin-1 ββββ Expression during Orthodontic

Tooth Movement

Won Hee Lim

The Graduate School

Yonsei University

Department of Dental Science

Effects of Doxycycline and Corticotomy on

Interleukin-1 ββββ Expression during Orthodontic

Tooth Movement

A Dissertation

Submitted to the Department of Dental Science

and the Graduate School of Yonsei University

in partial fulfillment of the

requirements for the degree of

Doctor of Philosophy of Dental Science

Won Hee Lim

June 2007

감사의 글

모든 순간 마다 보이지 않는 세심함으로 인도해 주신 하나님께 감사를 드

립니다. 본 논문이 완성되기까지 부족한 저를 항상 격려해 주시고 사랑으로

이끌어 주신 백형선 교수님께 깊은 감사를 드립니다. 그리고, 어려웠던 유학

시절부터 깊은 사랑을 베풀어 주신 김종관 교수님께 말도 다 할 수 없는 감

사를 드립니다. 삼년의 시간 동안 분에 넘치는 사랑을 주신 전윤식 과장님께

는 어떻게 말로 표현할 수 없는 감사를 올립니다. 학창 시절부터 지도 교수

님으로 사랑과 격려를 주신 이승일 교수님께도 깊은 감사를 드립니다. 세심

한 지도를 해주신 황충주 과장님께도 깊은 감사를 올립니다.

끊임 없는 이해와 사랑을 베풀어 주신 양가 어머님께 감사드리고 마지막으

로 사랑하는 남편에게 사랑과 고마움의 마음을 담아 전합니다.

모든 분께 진심으로 감사 드립니다.

2007년 6월

저자 씀

Table of Contents

Abstracts (English) ·····································································iii

I. Introduction···························································································1

II. Materials and Methods

A. Animals·····················································································4

B. Experimental Procedures ·························································4

C. Real Time RT-PCR ···································································5

D. Tooth Movement ·······································································8

E. Statistical Analysis ··································································10

III. Results ·······························································································11

IV. Discussion·························································································22

V. Conclusion ·························································································26

References······························································································27

Figure Legends ······················································································32

Abstract (Korean)···················································································34

i

List of Figures and Tables

Table 1. Genes analyzed by quantitative TaqMan PCR·································· 8

Figure 1. Schematic drawing of the rat model (A) orthodontic appliance placed (B)

orthodontic appliance placed after corticotomy·········································6

Figure 2. Landmarks on lateral cephalometric radiographs. Oc, most posterior point of

squama occipitalis; Pa, most superior point of parietal bone; T, most inferior

point of tympanic bone; Na, most anterior point of nasal bone ···················9

Figure 3. IL-1β mRNA expression (Means and SEM) in the no doxycycline + appliance

group (NDA)·····························································································12

Figure 4. IL-1β mRNA expression (Means and SEM) in the doxycycline + appliance

group (DA) ·······························································································13

Figure 5. IL-1β mRNA expression (Means and SEM) on pressure side for the DA and

NDA groups······························································································14

Figure 6. IL-1β mRNA expression (Means and SEM) on control side for the DA and

NDA groups····························································································15

Figure 7. mRNA levels (relative to control) for IL-1β in the corticotomy + appliance

group (CA) ·······························································································17

Figure 8. mRNA levels (relative to control) for IL-1β per group on pressure side in

CA·············································································································18

Figure 9. mRNA levels (relative to control) for IL-1β per group on control side in

CA·············································································································19

Figure 10. Tooth movement in the DA and NDA groups ··········································20

Figure 11. Tooth movement in the CA and A group··················································21

ii

Abstract

Effects of Doxycycline and Corticotomy on Interleukin-1β

Expression during Orthodontic Tooth Movement

Backgrounds: Cytokines are thought to play an important role in bone

remodeling during tooth movement. The aim of this study was to investigate the effect

of systemic administration of doxycycline and corticotomy on expression of Interleukin-

1β(IL-1β) during orthodontic tooth movement.

Methods: Real time reverse transcription polymerase chain reaction was

performed to measure messenger RNA (mRNA) expression of IL-1β at day 7 and 14

following application of orthodontic force to the maxillary first molar in 36 nine-week-old

male Wistar rats. Doxycycline was administrated throughout the study in 9 animals

(doxycycline + appliance group:DA) while other 9 animals served as treatment controls

(no doxycycline + appliance group:NDA). In 9 of these animals corticotomy was

performed after insertion of orthodontic appliances (corticotomy + appliance group:CA)

while the remaining 9 animals received only the orthodontic appliance (appliance

group:A). The animals were euthanized day 7 and 14 after appliance insertion and

gingival tissue samples were obtained for analysis.

iii

Results: A similar expression of IL-1β was shown at day 7 following application

of force in both DA and NDA groups. IL-1β expression at day 14 was significantly

decreased compared to that at day 7 for both DA and NDA groups. The increased

expression of IL-1β was detected on CA group seven days after the application of force

and these differences were statistically significant between these CA and A groups

fourteen days after experiment.

Conclusion: The results suggest that expression of IL-1β during orthodontic

tooth movement were not affected by administration of doxycycline, but the levels of

cytokine both day 7 and day 14 were increased in corticotomy groups. It may support

the hypothesis that osteoclast recruitment stimulated by orthodontic force was not

influenced by doxycycline, but regional acceleratory phenomenon after performance of

corticotomy increases bone remodeling during orthodontic tooth movement.

KEY WORDS: Doxycycline, Corticotomy, Tooth movement, IL-1β Expression

iv

1

Effects of Doxycycline and corticotomy on Interleukin-1β

Expression during Orthodontic Tooth Movement

Won Hee Lim, D.D.S., M.S.

Department of Dental Science, Graduate School, Yonsei University

(Directed by Prof. Hyoung Seon Baik, D.D.S., M.S.D., PhD.)

I. Introduction

Pressure onto the periodontal ligament (PDL) space induced by orthodontic forces

results in vascular compression, which leads to cellular activation and the release of

pro-inflammatory molecules such as prostaglandins and cytokines.1 Prostaglandin E2

(PGE2) and interleukin-1β (IL-1β) levels in human gingival crevicular fluid (GCF) has

been shown to be elevated during orthodontic tooth movement.2 Thus it appears that

these inflammatory mediators may regulate biological processes related to alveolar

bone remodeling for initiation of tooth movement, although the mechanism is not yet

fully understood.1,3

PGE has been known to be closely involved in bone resorption.4 Yamasake et al. has

shown that the rate of tooth movement was almost double in sites receiving PGE1

injections compared to vehicle-control.5 Conversely, anti-inflammatory drugs may

reduce the rate of bone resorption by interfering with biologic mechanisms induced by

2

PGs.6,7 IL-1β, a major physiologic form of IL-1, is a known potent cytokine involved in

initiation of bone resorption.8 Interestingly, IL-1β may induce elevation of PGE

synthesis in a dose- and time-related order.9 Inversely, administration of IL-1β and/or

PGE significantly enhanced the rate of tooth movement.10 These findings suggest that

elevation of these mediator levels may serve as a marker for increased local bone

remodeling.11

It has been shown that systemic and local administration of pharmaceutical agents may

affect tooth movement.12-14 As the use of antibiotics increases, this may cause

variations in normal bone turnover in orthodontic patients.15 Doxycycline modulates

alveolar bone metabolism, most likely due to an inhibitory effect on bone resorption

including inhibition of several matrix metalloproteinases.16 In still other studies,

doxycycline has been shown to affect osteoclast function.17 Tetracyclines have also

been shown to reduce expression of cytokines involved in bone resorption including IL-

1 and TNF-α.18 Minocycline added to gingival fibroblast cultures inhibited synthesis of

PGE2.19 Moreover, it has been shown that minocycline may prevent a decrease of bone

mineral density in ovariectomized rats.20

It has been shown that healing activity was dramatically increased adjacent to the

injury site in osseous tissue.21 This biologic process, regional acceleratory

phenomenon (RAP), potentiates healing by localized burst of hard and soft tissue

remodeling and involves increase in bone turnover and decrease in regional bone

density.22 The characteristics of RAP during initial phase appears an enhanced porosity

in cortical bone due to increase in osteoclastic activity.23 Interestingly, tooth movement

3

was enhanced in rats with osteoporosis.24 These findings suggest that localized

transient osteoporosis, which means increased mobilization of calcium, decreased

bone density and increased bone turnover, result in rapid tooth movement after RAP

invoked by corticotomy.25 In still other studies, there has been strong indirect evidence

that the physiologic events associated with RAP result in corticotomy-facilitated tooth

movement.26 PGE2 has also been shown to facilitate RAP in the repair of experimental

fractures.22 However, an assessment of PGE2 and IL-1β after corticotomy have not

been made to see the RAP.

Administration of doxycycline and corticotomy during orthodontic tooth movement

might add interacting factors for the study of osteoclast.1,13,18 The aim of this study was

to investigate whether systemic administration of doxycline and corticotomy induced

different gene transcription of IL-1β in the gingival tissues involved in orthodontic tooth

movement.

4

II. Material and Methods

A. Animals

Thirty six nine-week-old, male Wistar rats, approximate weight of 280 g, from Yonsei

Univerisity vivarium were used. All animals were kept in stainless-steel cages in air-

conditioning and subject to standard 12-hour light/dark cycle. They were fed with a

pellet diet (8811M0001, Extrusion, Superfeed Co., LTD, Gangwon, Korea) and tap

water ad libitum. They were checked everyday in regard to their health status.

Doxycycline was administrated throughout the study in 9 animals (doxycycline +

appliance group:DA) while other 9 animals served as treatment controls (no

doxycycline + appliance group:NDA). In 9 of these animals corticotomy was performed

after insertion of orthodontic appliances (corticotomy + appliance group:CA) while the

remaining 9 animals received only the orthodontic appliance (appliance group:A). From

each group, the animals were euthanized day 7 and day 14.

B. Experimental Procedures

A constant force of 20 g was generated using a closed coil spring (Sentalloy, 0.009 x

0.036, Tomy Incorporated, Tokyo, Japan) to move the maxillary first molar mesially. The

springs were attached to the maxillary left first molar and the maxillary incisors using a

stainless steel ligature wires. Light-curing bonding

Material (3M Unitek, Nonrovia, CA, USA) was applied on perforations produced by

diamond bur along the mesio-lingual and disto-lingual line angle of the maxillary first

molar and the distal sides of the incisors to ensure maximum retention of the coil spring

5

(Figure 1A). Reactivation was not done during the study period. Animals scheduled for

antibiotic treatment received 5 mg/kg bodyweight/day.doxycycline (Dentistar, Hana

Pharmaceutical company, Hwa Sung, Kyonggido, Korea) added to tap water. For CA

group, the vertical corticotomy cuts without flap reflection were performed through the

cortical layer of the bone using fine fissure bur (Figure 1B). A GluStitch (Salvin Dental

Specialties, Inc., NC, USA) was applied to improve tissue adhesion around the wound

area on the rats receiving corticotomy.

The weight of the animals was recorded on the day of the appliance insertion and

before death. All procedures were performed using general anesthesia induced by

subcutaneous injection of Zoletil (Tiletamine 125 ml, Zolazepam 125 ml; 0.04 ml Virbac,

060516 carros, France) and Rompun (Xylazire hydroxychloride 23.32 mg/ml; 0.01 ml

Bayer AG, 51368 Leverkusen, German). At the end of each experimental period the

animals were euthanized using an overdose of an anesthetic. The gingiva around the

maxillary first molar was excised, frozen in liquid nitrogen and kept at -80°C until use.

Real time reverse transcription polymerase chain reaction (real time RT-PCR) was

used to quantify IL-1β as reported elsewhere.27,28

C. Real Time RT-PCR

1. RNA extraction

TRI zol reagent (Molecular Research Center, Inc., Cincinnati, OH, USA)was

used to extract total RNA from each sample

2. cDNA synthesis

One µg total RNA was reverse transcribed into cDNA using a Promega’s

6

A

B

Figure 1. Schematic drawing of the rat model (A) orthodontic appliance placed (B)

orthodontic appliance placed after corticotomy

7

Reverse Transcription system (Promega Corp., Madison, WI, USA). Reverse

transcriptase was added in the mixture containing RT POX buffer, 2.5 mM MgCl2,

Oligo (dT) primer, dNTP Mix and Rnasin. The reagents were incubated at 42°C

for 15 min, and then heated to 95°C for 5 min.

3. Real time RT-PCR

Real time RT-PCR was performed in an ABI Prism 7000 Sequence Detection

System (Applied Biosystems, Foster City, CA, USA). Primers and probes of IL-

1β and glyceraldehydes-3-phosphate dehydrogenase (GAPDH) are shown in

Table I. PCR amplifications were performed in a total volume of 25 µl,

containing 50ng cDNA sample, 1X TaqMan Universal PCR Master Mix, 300 nM

of each primer and 250 nM TaqMan probe following the manufacturer’s

protocol. Initial thermal cycling conditions were 2 min at 50°C and then 10 min

at 95°C. Cycle conditions for IL-1β and GAPDH were 15 sec at 95°C and 1 min

at 60°C, and RNAs for IL-1β and GAPDH were amplified by 40 cycles. For

PCR, oligonucleotide hybridization probe was labeled with 6-

carboxyfluorescein as reporter fluorescence and 6-carbocy-tetramethy-

rhodamine as quencher fluorescence.

4. Quantification using the Standard Curve Method

For quantification of results, cDNA fragments of the known sequences were

constructed as standards. The amount of GAPDH mRNA and mRNA levels of

cytokine were measured using this Standard Curve method. The results were

adjusted by the amount of GAPDH mRNA. Levels of these mRNA in each

sample were expressed as the ratio versus that of control. Every sample was

measured in triplicate.

8

Table 1. Genes analyzed by quantitative TaqMan PCR

Gene Primer/probe Sequence

IL-1β Forward primer

Reverse primer

Probe

CAA CCA ACA AGT GAT ATT CTC CAT G

GAT CCA CAC TCT CCA GCT GCA

CTG TGT AAT GAA AGA CGG CAC ACC CAC C

TNF-α Forward primer

Reverse primer

Probe

CAT CTT CTC AAA ATT CGA GTG ACA A

TGG GAG TAG ACA AGG TAC AAC CC

CAC GTC GTA GCA AAC CAC CAA GTG GA

Sequences for the primers and probes are shown in 5’to 3’ orientation; probes contain

a FAM on the 5’ end and a TAMRA on the 3’ end.

D. Tooth Movement

Each animal was placed in a specially made craniostat for standardized radiography. A

wooden wedge was placed into each ear to ensure position. An intraoral radiographic

apparatus (IMS 2000 Inermecs Co., LTD, Seoul, Korea) was used with dental film

(Insight Kodak Co., Rochester, NY, USA). The amount of tooth movement was

measured on lateral cranial radiographic images by one masked examiner. Horizontal

and vertical reference lines were used for cephalometric measurement. The horizontal

reference plane was defined as the most anterior point of the nasal bone and the most

posterior point of the squama occipitalis, and the vertical reference plane was as the

most superior point of the parietal bone and the most inferior point of the tympanic

9

bone.29 The two parallel lines to the parietal-tympanic plane were used to measure the

amount of mesial movement of the maxillary first molar (Figure 2). One line was drawn

on the most anterior point of the anterior border of the maxillary second molar crown,

and the other on the most posterior point of the posterior border of the maxillary first

molar crown.29 The distance between the maxillary first and second molar digitized with

a film scanner (PowerLook 1100, UMAX, Hyo Sung Electric Light LTD, Seoul, Korea)

was measured using cephalometric image analysis (V-Ceph. Cybermed Inc, Seoul,

Korea).30 The distance was measured thrice to statistically evaluate the reproducibility

of the examiner. The examiner exhibited high reproducibility.

Figure 2. Landmarks on lateral cephalometric radiographs. Oc, most posterior point of

squama occipitalis; Pa, most superior point of parietal bone; T, most inferior point of

tympanic bone; Na, most anterior point of nasal bone.

10

E. Statistical Analysis

Data were expressed as means ± standard error of the mean and analyzed by

nonparametric standard techniques such as Wilcoxon and Mann-Whitney tests as

appropriate. A p-value <0.05 was required for statistical significant.

11

III. Results

The orthodontically treated animals drank and ate less during the first 3-4 days of study

but rebounded to normal food and water ingestion and did not seem to be bothered by

the orthodontic appliance, hence body weight increased over the experimental period.

Four animals were excluded from the analysis due to appliance displacement.

In the NDA group, a statistically significant difference in mRNA levels for IL-1β was

found between the pressure side (left side) and the contralateral control side(right side).

mRNA expression of IL-1β on the pressure side was greater at 7 days compared with

at 14 days, while that on the control side showed no difference between at 7 and 14

days (Figure 3). The similar results were observed in the DA group (Figure 4).

Comparing the NDA group to the DA group, no difference was found in IL-1β mRNA

expression on the pressure side day 7 and 14. On day 14, IL-1β mRNA expression was

statistically significantly decreased on both groups (Figure 5). On control side, there

was no difference between the groups as well. On the other hand, IL-1β mRNA

expression on control side of DA group revealed statistically significant increase from

day 7 to day 14 (Figure 6).

12

Figure 3. IL-1β mRNA expression (Means and SEM) in the no doxycycline + appliance

group (NDA). * P < 0.05

13

Figure 4. IL-1β mRNA expression (Means and SEM) in the doxycycline + appliance

group (DA). * P < 0.05

14

Figure 5. IL-1β mRNA expression (Means and SEM) on pressure side for the DA and

NDA groups. * P < 0.05

15

Figure 6. IL-1β mRNA expression (Means and SEM) on control side for the DA and

NDA groups. * P < 0.05

16

In the CA group, a statistically significant difference in IL-1β mRNA expression was

found between the pressure side and the control side at day 7 and 14. IL-1β mRNA

expression on the pressure side was greater at day 7 compared to day 14 (Figure 7).

Comparing the A group to the CA group, no significant difference was found in IL-1β

mRNA expression on the pressure side day 7. On the other hand, IL-1β mRNA

expression in the CA group showed a statistically significant expression on day 14

(Figure 8). On the other hand, IL-1β mRNA expression on control side of CA group

revealed statistically significant difference on day 7 compared to that in the A group

(Figure 9).

No significant difference in tooth movement was found between the DA and NDA groups

day 7 and day 14 (Figure10). However, a statistically significant increase in tooth

movement was found between the A and CA groups (Figure 11).

17

Figure 7. mRNA levels (relative to control) for IL-1β in the corticotomy + appliance

group (CA). * P <0.05

18

Figure 8. mRNA levels (relative to control) for IL-1β per group on pressure side in CA.

* P <0.05

19

Figure 9. mRNA levels (relative to control) for IL-1β per group on control side in CA.

* P <0.05

20

Figure 10. Tooth movement in the DA and NDA groups.

21

Figure 11. Tooth movement in the CA and A group. * P <0.05

22

IV. Discussion

Tooth movement has, as would be expected, an impact on the magnitude of

periodontal tissue response.1 This influence can be modulated by the administration of

doxycycline, probably because of the differences in alveolar bone response.19,31-32

Tetracycline has been known to act as a collagenase inhibitor, and influence the

recruitment and function of osteoclasts.33-43 Additionally, the absolute volume of the

alveolar bone was significantly increased in rats received doxycycline under

orthodontic force.19 These results elicited evaluation of the biologic process on cellular

levels related to tooth movement after administration of doxycycline.

There was a statistically significant decrease in IL-1β mRNA expression from day 7 to

day 14 for both DA and NDA groups. It coincides with the study in which the maximum

levels in IL-1β and IL-6 were detected on day 3 following application of orthodontic

force and then decreased on day 7 and 10 for return to the baseline levels.44

There was no difference of IL-1β mRNA expression between the NDA and the DA

groups at any time point. It was demonstrated that odontoclast and osteoclast

recruitment stimulated by orthodontic force was not affected by doxycycline treatment

on day 7.19 Therefore, it can be speculated that doxycycline treatment may not affect a

biologic process related to tooth movement for short time period. However, care should

be taken on administration of doxycycline for long time period because IL-1β mRNA

expression on control sides in the DA group was statistically significant increased from

day 7 to day 14.

23

IL-1β mRNA expression on pressure side at day 14 is significantly greater in the CA

group compared to the A group. This trend could be explained as a reflection of the

regional acceleratory phenomenon (RAP) where healing activity was dramatically

increased adjacent to the injury site after surgical wounding of the osseous tissue.21,22 It

was reported that evidence of RAP was first observed 10 days after mucoperisteal

surgery in rats.45 It may be interpreted that IL-1β mRNA expression in the CA group

may be affected on day 14 in this study.

IL-1β mRNA expression on control side at day 7 is significantly greater in the CA group

compared to the A group. A plausible explanation may be found in a previous study that

tissue reactions to mechanical force were not localized to the loaded tooth.46 Moreover,

it appeared that tissue responses extended to the adjacent tooth, like the whole

hemimaxilla reacted to the orthodontic force applied to the first molar.

The primary aim of this study was to investigate the cytokines expression using RT-

PCR and the distance between the maxillary first and second molars was measured to

use as an indicator of the possible tooth movement. No statistically significant

difference in the rate of orthodontic tooth movement was found between DA and NDA

groups throughout the experiment. However, a statistically significant difference in the

rate of orthodontic tooth movement was found between CA and A groups on day 7,

although these tooth movement may not reflect the minor displacement due to

inaccuracy of the assessment method.

As antibiotics including tetracycline and erythromycine are frequently used for acne

24

treatment, administration of antibiotics may result in variations in normal bone turnover

during orthodontic treatment.15,47 Doxycycline was selected among tetracyclines for this

study, in part, because of the potent collagenase inhibitor, and because it has been

also known to decrease the total number of osteoclasts and prevent alveolar bone loss

following periodontal surgery in rats.19 The outcome of this study could be clinically

applied in that it is possible to treat patients undergoing short- term antibiotics therapy

because our data seem to indicate that the levels of cytokines, after orthodontic tooth

movement, were not affected during experimental periods. The rate of orthodontic tooth

movement was not affected by administration of doxycycline, either. A previous study

also showed that tetracycline has a beneficial effect on tooth movement by reducing

the amount of root resorption.19 A plausible explanation for decreased root resorption is

primarily by the inhibition of matrix metalloproteinases.14 In addition, tetracycline could

prevent gingival inflammation during tooth movement.34 Taken together, the orthodontic

treatment may be continued as usual for the short-term administration of doxycycline

during orthodontic treatment. However, effects of doxycyline during orthodontic

treatment have to be undertaken with larger number of samples before the clinical

application of this concept. Future research will be also focused on the influences of

cytokines on the individual activity after administration of doxycycline depending on

dose and duration.

The outcome of this study could provide the biologic process for fast rate of tooth

movement following application of orthodontic force combined by corticotomy. Our data

seem to indicate that the levels of cytokine, after orthodontic tooth movement followed

by corticotomy, were elevated for both on day 7 and on day 14. Especially, the

25

differences in the levels of cytokine on day 14 were statistically significant. The rate of

orthodontic tooth movement was also increased in corticotomy groups. Taken together,

the orthodontic treatment combined with corticotomy may be performed in cases where

reduction of orthodontic therapy treatment time is required.

The cytokines levels evaluated in human GCF did not provide the information of origin

in cytokines; at transcription, at translation or simply a product.3 For this reason, the

mRNA expression of these cytokines using RT-PCR was needed to investigate the

cellular induction of cytokines. RT-PCR has the advantage of quantification of the

cytokines, especially in cases where the available samples to be analyzed are too

small to quantify the cytokines at the protein level. 27 In addition, RT-PCR is thought to

be a very powerful and sensitive method, while the ELISA technique for cytokine

protein detection allows only a limited number of cytokines.27

26

V. Conclusion

Inflammatory cytokines expressed during orthodontic tooth movement can be

quantified on a cellular level using RT-PCR. This study evaluated the effect of

doxycycline and corticotomy on IL-1β, believed to play important roles in bone

remodeling following application of orthodontic forces. The results suggest that the

expression of IL-1β is not affected by doxycycline, but a statistically significant

expression of IL-1β was shown at day 14 in the CA groups.

These observations support the hypothesis that osteoclast recruitment stimulated by

orthodontic force is not influenced by doxycycline, and regional acceleratory

phenomenon after performance of corticotomy increases bone remodeling during

orthodontic tooth movement.

Moreover, our study has shown that RT-PCR appears powerful and sensitive method to

quantify mRNA expression in cases where the available samples too small to quantify

the cytokines at the protein level and cellular induction of cytokines with a very short

half-life needs to be assessed during orthodontic tooth movement.

27

References

1. Krishnan V, Davidovitch Z. Cellular, molecular, and tissue-level reactions to

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Figure Legends

Figure 1. Schematic drawing of the rat model (A) orthodontic appliance placed (B)

orthodontic appliance placed after corticotomy

Figure 2. Landmarks on lateral cephalometric radiographs. Oc, most posterior point of

squama occipitalis; Pa, most superior point of parietal bone; T, most inferior point of

tympanic bone; Na, most anterior point of nasal bone.

Figure 3. IL-1β mRNA expression in the no doxycycline + appliance group:NDA.

* P < 0.05

Figure 4. IL-1β mRNA expression in the doxycycline + appliance group: DA.

* P < 0.05

Figure 5. IL-1β mRNA expression on pressure side for the DA and NDA groups.

* P < 0.05

Figure 6. IL-1β mRNA expression on control side for the DA and NDA groups.

* P < 0.05

Figure 7. mRNA levels for IL-1β in the corticotomy + appliance group: CA.

* P <0.05

33

Figure 8. mRNA levels for IL-1β per group on pressure side in CA. * P <0.05

Figure 9. mRNA levels for IL-1β per group on control side in CA. * P <0.05

Figure 10. Tooth movement in the DA and NDA groups.

Figure 11. Tooth movement in the CA and A group. * P <0.05

34

국문국문국문국문 요약요약요약요약

독씨싸이클린독씨싸이클린독씨싸이클린독씨싸이클린 (Doxycycline)과과과과 코티카토미코티카토미코티카토미코티카토미 (Corticotomy)가가가가 교정적교정적교정적교정적 치아치아치아치아

이동시이동시이동시이동시 Interleukin-1ββββ(IL-1ββββ)에에에에 미치는미치는미치는미치는 영향영향영향영향

연세대학교 대학원 치의학과

(지도 백형선 교수님)

임원희

싸이토카인 (cytokines)은 교정 치료시 일어나는 골 개조에 중요한 역할을 하는 것

으로 알려져 있다. 이 실험의 목적은 치아 이동시 독시싸이클린 (doxycycline)의

투여와 corticotomy 시행시 Interleukin-1β(IL-1β) 표현의 변화를 보고자 함이다.

9주된 36마리의 수컷 위스타(Wistar) 쥐의 상악 제일구치에 교정력을 가한 후에

IL-1β messenger RNA(mRNA)의 표현을 보고자 real time reverse transcription

polymerase chain reaction을 행하였다. 9마리의 쥐에서는 독시싸이클린 투여 없이

치아 이동을 위한 교정 장치만 걸고, 다른 9마리의 쥐에서는 치아 교정 장치와 함

께 독시싸이클린을 투여하였다. 또 다른 9마리의 쥐에서는 교정 장치를 건 후,

corticotomy를 시행했고, 나머지 9마리 쥐는 교정 장치만 걸었다. 6마리의 쥐는 아

무 것도 시행하지 않았다. 쥐들은 교정 장치 삽입 7일 혹은 14일 후에 희생되었으

며 분석을 위해 상악 제일구치 부위의 잇몸 조직을 채취하였다.

35

독시싸이클린을 투여한 군과 투여하지 않은 군을 비교 시 7일째에는 비슷한 IL-1β

의 표현을 보였고, 14일에서는 두 그룹 모두에서 IL-1β의 양이 감소하였다.

Corticotomy를 시행한 군과 시행하지 않은 군을 비교 할 때 7일과 14일에서

corticotomy를 행하고 치아 이동을 한 군에서 IL-1β의 양이 크게 증가하였다.

결론적으로, 치아 이동 시 doxycycline의 투여는 IL-1β의 표현에 영향을 주지 않

았으나, corticotomy와 함께 치아 이동을 한 경우에는 IL-1β의 증가를 볼 수 있었

다.

핵심되는 말: 독시싸이클린 (doxycycline), 코티카토미 (corticotomy). 치아 이동, IL-

1β 표현 (expression)