면역조직화학적 방법에 의한 흰쥐 후각상피 재생에 대한 비타민 A의 영향

Although Olfaction is a very primitive sense, it is still poorly understood. Recently, new research into nerve cell transduction and regeneration is unlocking mechanisms that may help in treating patient with olfactory and other neural problems.

During development of the olfactory epithelium, groups of cells continuously divide, migrate, and differentiate to form mature olfactory receptor neurons. And among the four main cell types of olfactory epithelium, basal cells act as stem cells to replace the dying olfactory recepter cells. This capacity for renewal of the receptor cells continues throughout the life of the animal and appears to be unique among mammalian neural systems.

Evidence for morphological and biochemical studies has demonstrated that neuronal cell death and subsequent renewal can be enhanced by turnover induced by chemical destruction of the olfactory epithelium by zinc sulfate lavage or bulbectomy.

In the treatment of anosmia without obstructive nasal and sinus disease, although about 30% of patient regain olfactory ability spontaneously, there is no definite therapy about it.

Various vitamins and minerals have been promoted for the treatment of olfactory loss. Unfortunately, none of these has been succesful in controlled trials or predictable enough to warrant their use. Vitamin A has been suggested because it is necessary for repair of epithelium, because rats deficit in vitamin A become anosmia, and because mammalian olfactory epithelium contains considerable amounts of it.

Therefore author tried vitamin A subcutaneous injection to the mouse after chemical destruction of olfactory epithelium by 1% zinc sulfate lavage. And their regeneration was examined by immunohistochmical study with cytokeratin specific for basal cell and neuron- specific enoIase(NSE) specific for olfactory receptor cells.

The result showed that more intense cytokeratin immunoreactivity was seen in the vitamin A injected animals than not injected ones. But NSE reactivity of vitamin A injected group demonstrated a staining pattern similar to that seen in the not injected one.

It suggests that vitamin A induces more enhanced proliferative response of basal cell after trauma of olfactory epithelium, which means that it would be possible that vitamin A is effective for treatment of anosmia by olfactory neuron damage. But vitamin A did not promote proliferation of olfactory receptor cells directly in 3 weeks after trauma. So we will have further study about this phenomenon.