STORAGE O F TRYPAN BLTTE I N THE INTERNAL EAR O F THE RAT1

B E N J A M I S SPECTOII l )epurl?i imt of Aiiatoniy, T u f t s College Mcdzcal School, Boston, Mussacliusetts

T W O PL.4TES (FOKR FIGURES)

There have been few attempts to study the prcseiice of phagoeptes in the organ of Corti and its associated periotie spaces by nieaiis of iiilra-vitam stiiiiiiiig. It is of special interest, therefore, to learii something of tlic distributioii of such cells in the internal ear. T t is well eatablislied that the histiocytes of most all tissues possess in pi~+eniinent degree the capacity for storing in theii. cytoplasni the particles of a colloidal solution of trppan blue. The following brief report gives experimental evidence of the fact that the histiocytes in the internal ear storc particles of this dye in their c i t o - plasm.

MATERIAL AND ME‘I’NODS

Ten albino rats (Wistar strain) ranging in age from 12 to 45 days were given daily injections of 1 cc. of a 1% solutioii of the colloidal dye trypan blue. The solution, after being filtered and sterilized, was injected into the animals by the iritra-abdominal route. The animals were killed at intervals froin 24 to 68 hours aiid the otic capsules immediately fixed in Hcideiiliaiii’s “Susa” mixture. The specimens were de- calcified in 5%) aqueous solution of tricliloi*acetic acid a d embedded in paraffin. The blocks of tissue were cut serially at 10 niicra and stained with Maycr’s paracarmine and orange G.

‘Aided by a grant f rom the Challtoii Research Fund, Tufts College Medical Sehool.

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84 BEN J A M I N SPECTOR

OBSERVATIONS

A careful examination of the sections of the experimental otic capsules revealed the presence of large oval or round cells and occasional elongated spindle shaped cells containing granules of trypan blue in the form of dust-like particles, small discrete granules or larger masses of agglutinated granules. The distribution of these histiocytes was exten- sive. There were abundant Iiiacrophages with prominent dye inclusions concentrated around the foot of the stapes and the tympanic membrane. The scala tympani and the scala vesti- buli showed many of these cells applied to their walls. Within the rriodiolus and about the nerve fibers numerous histiocytes filled with blue granules of varying size were clearly in evi- dence. A few spiiitlle shaped d l s were observed lining th(3 basilar membrane. An interesting observation was the pres- ence of a large liistiocyte, laden with dye, within the “tunnel” of the spiral organ. One also observed many histiocytes intensely stained with the vital dye about the semicircular ducts. There was no evidence of devitalized areas of proto- plasm. A careful search revealed no cells laden with dye particles as part of a reticulum. All of the cells were free macrophages. The accompanying colored figures clearly illustrate the distribution of the histiocytes in selected areas of the internal ear.

SUMMARY

1. Following intra-abdominal iirjections of trypan blue in albino rats, the histiocytes in the internal ear react to the storage of this dye in a manner characteristic of histiocytes found in most all tissues.

2. The storage of the transported dye was found in the histiocytes lining the periotic spaces, the basilar membrane, and the tympanic membrane. I n addition, the blue granules were stored in the histiocytes about the stapes, the modiolus, the nerve fibers and the semicircular ducts.

TRYPAN BLUE I N INTERNAL EAR OF RAT 85

LITERATURE CITEIJ

HODJAKOFF, N. D. 1937 Uher die Ausbreitung voii Trgpan hlau hci rler Ein- fiihruiig in das hlittelolir. Arkli. So\ et. Oto Rmo-I~:iriiig., i.t.tl. 3, 113- 121, 1937. Rbst. Zeiitmlblatt f u r IIals-Saseii uiid Olirmheilkmtde, Bd. 29, Hefte 4, 8. 216, November, 1937.

PLATE 1

EXPLANATION OF FIGUR.ES

1

2

Note: the large histiocyte in the !‘tunnel” of the spiral organ; the elongated cells at the basilar membrane; the macrophages lining the scala tympani. x 280.

Shows the detail in the storage of the dye. X 1450.

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TRYPAN BLUE I N INTERNAL EAR O F R-iY BENJAMIN SPECTOR

PLATE 1

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PLATE 2

EXPLANATION OF FIGURES

3

4

Portion of the tympanic membrane showing histiocytes laden with particles

Section through the wall of the lateral semicircular duct and its surround of trypan blue. X 500.

ing tissue. Note the character of the dye inclusions in the histiocytes. x 450.

TRYPAN BLUE IN INTERNAL EAR O F R.\T BENJAMIN SPECTOB

PLATE 2

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