Inflammation 145

15.25 REGULATION OF MANGANESE SUPEROXIDE DISMUTASE (MnSOD) IN HEPATOCYTES AND INTESTINAL EPITHELIAL CELLS BY INFIAMMATORY MEDIATORS Harry S. Nick, William C. Dougall, and John Valentine Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL 32610, Alachua, U.S.A.

We have investigated the effects of interleukin-6 (IL-6) on MnSOD gene expression in primary cultures of rat hepatocytes, and the effects of hyperoxia, LPS and tumor necrosis factor (TNF) in rat intestinal epithelial cells. Treatment of hepatocytes with IL-6 caused a large transient increase in steady-state MnSOD mRNA as analyzed by Northern blots. Exposure of adult or fetal rat intestinal cells to LPS or TNF resulted in a dramatic increase in MnSOD mRNA within I hr of exposure, whereas 95% 0 z had no effect. These effects are cell type-specific, based on the lack of reciprocal responses: IL-6 has no effect on intestinal cells, while MnSOD is not responsive to TNF and LPS in hepatocytes. The inductions in both cell types were completely abolished in the presence of the transcriptional exhibitor, actinomycin D, but were not effected by inhibition of protein synthesis via cycloheximide. We have demonstrated that the MnSOD is regulated in a cell type and stimulus specific manner by inflammatory mediators which control the. acute phase response.

SIPEROXIDE ANION PRODUCTION BY HACROPRAGES IN STREPTOZOTOCIN-INDUCED DIABETIC RATS Kiyoshi 0hura. Keigo Ogata, Mitsuko Shinohara. Yoshihiko Komon. Masakazu Heri. Department of Pharmacolngy. Osaka Dental University, Osaka 540, Japan

Diabetic pa t i en t s are vulnerable to periodontal disease because of impaired defense mechanisms. To elucidate bac ter ic ida l ab i l i t y , superoxide anion (0,-) production by M ~ in diabetic rats and the effect of iv~'zulin treat- ment were examined. Fifty-three g-week-old male Wistar rats each weighing 150g to I60g were used. Diabetes was induced by a single intraperiteneal injec- tion of streptozotocin (60mg/Kg) dissolved in citrate buffer (pll4.5). Eight weeks after the injection, intra- peritoneal M # were obtained from 28 untreated diabetic. 6 diabetic insulin-treated, and 19 control rats. Blood glucose and serum insulin levels were determined by glucose oxidase method and one step enzyme immunoaasay. respectively. Oz- production was measured by the cytochrome c reduction method. Opsenized zymosan, phorbol myristate acetateund Ca ionophore A23187 were used as stimulants. Oz- production by M~ in diabetic rats was significantly lower than that in control rats for every stimulast (p<0.001). There was a negative correlation between Oz- production and blood glucose level, and a positive correlation between Oz" production and serum insulin level. In insulin-treatsd rats, blood glucose level was significantly lower and body weight was significantly greater, although the 0,- production by M~ was not significantly higher than that in diabetic rats. These results indicate that impaired O,- production is a factor influencing the bactericidal ability of M ~ in diabetic rats.

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15.27 EVIDENCE OF RADICAL ACTIVITY IN HUMAN ASTHMA D.J. Pearson, V. Suarez-Mendez, S Owen, R. O'Driscoll and A. Woodcock. Department of Medicine, University Hospital of South Manchester, Manchester M20 8LR, UK.

The p h y s i o l o g i c a l a b n o r m a l i t i e s o f as thma a r e s econda ry to e o s i n o p h i l i c i n f l a m m a t i o n . In c l a s s i c a l models o f t h e c o n d i t i o n , t he i n f l a m m a t i o n r e s u l t s from I g E - F e ~ I - r e c e p t o r t r i g g e r e d r e l e a s e o f h i s t a m i n e and l e u k o t r i e n e s from mast c e l l s , w i t h s e c o n d a r y e o s i n o p h i l i n f i l t r a t i o n . However F c ~ I I - r e c e p t o r t r i g g e r i n g o f e o s i n o p h i l s , p l a t e l e t s and macrophages i s a p a r t i c u l a r l y p o t e n t sou rce o f 02"and H202 s e c r e t i o n (compared to I g G - n e u t r o p h i l s t i m u l a t i o n ) . We t h e r e f o r e i n v e s t i g a t e d non- enzymic in vivo lipid peroxidation and the influence of antioxidants in human asthma.

C i r c u l a t i n g 9,11 l i n o l e i c a c i d (LA) d i e n e c o n j u g a t e l e v e l s and 9 , 1 1 / 9 , 1 2 molar r a t i o s were e i e v a t e d a t t h e t ime o f a c u t e e x a c e r b a t i o n s o f as thma, and c o r r e l a t e d s i g n i f i c a n t l y w i th a t t a c k s e v e r i t y as judged by Peak E x p i r a t o r y Flow Rate. In c h r o n i c a s t h m a t i c s u b j e c t s 9,11 LA i e v e l s and MR's were i n v e r s e l y r e l a t e d to serum se l en ium c o n c e n t r a t i o n .

Free radical activity and antioxidant modulation may be significant factors in allergic airway inflammation.

FREE RADICALS IN THE GENESIS OF ENDOTOXIN-INDUCED INTESTINAL MYOELECTRIC ALTERATIONS IN RAT Laurent Pons*, Marie T. Droy-Lefaix**, Pierre Braquet**, Lionel Bu~no* - * INRA Toulouse, • * IHB/IPSEN Research Laboratories, Le Plessis Robinson, FRANCE

Free radicals (FR) are involved in inflammatory processes and gastrointestinal lesions. This study was to determine whether FR are involved in endotoxin-induced intestinal myoelectric alterations. We also investigated the role of platelet-activating factor (PAF) in endotoxin- induced FR release. Intestinal myoelectric activity was recorded in fasted rats chronically implanted with electrodes in the duodeno-jejunum. Small intestinal myoelectric activity was characterized by the regular occurrence of migrating myoelectric complexes (MMCs). Endotoxin replaced the cyclic MMCs by a typical pattern, called "minute rhythm". PAF exhibited a similar pattern. Pretreatments with allopurinol, superoxide dismutase, dimethyl-sulfoxide signi- ficantly shortened endotoxin- and PAP-induced MMCs inhibition. Previous administration of BN 52021, a specific PAP antagonist blocked the effects of PAF on MMCs and reduced those of endotoxin. Partial blockade of endotoxin- induced alterations by BN 52021 was not improved by additionnal administration of any FR scavenger. It is concluded that I) PAP and FR contribute to the genesis of endotoxin-induced intestinal myoeleetric alterations 2) PAF partially acts via FR release, 3) FR involved in endotoxin-induced intestinal motor disorders proceed from the PAP pathway.

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