An Electron Microscopic Study on the Effect of Vitamin A Acid on Experimentally Induced Comedones in Rabbit

Lee, Kyung Sin; Myung, Ki Bum; Kook, Hong Il

Abstract

Comedones were induced at external ears of rabbits by daily application of 50% oleic acid in paraffin oil for 3 weeks. 13 cis-retinoic acid(RA) solution(0.1%)wae apllied to experimentally induced comedones. The morphologic changes around the epithelial lining of comedones were observed by transmission electron microscopy to define the effect of RA on comedones. In follicles treated with RA, the results were summarized as follows: l) The thickness of the stratum corneum of the epithelium was markedly decreased with widening of intercellular spaces. 2)The number of desomosomes and desmosoma1 bodies between horny cells was decreased. 3) Abnormally appeared tight junction in the stratum corneum and disappearance of membrane coating granules in the straurn granulosum were reversed to normal state, disappearance of tight junction and increment of membrane coating granule respectively by the application of RA. These observations suggest that RA has comedolytir. effect by decreasing cohesive- ness between horny cells.