Monitoring of Cell Migration and Apoptosis in Cerebellum of Juvenile Masu Salmon Oncorhynchus Masou After Injury

Abstract

Apoptosis in various cerebellar zones of juvenile masu salmon Oncorhynchus masou after mechanical injury was investigated by TUNEL-labeling. In the brain of 4 month-old juveniles of O. masou growth in different parts of cerebellum and proliferative activity in secondary matrix zones of cerebellum were continued. TUNEL-labeling was observed in the injured cerebellum 2 days after damage. The induction of proliferative activity in different matrix zones: granular eminences, dorsal part of molecular layer and surface layers of corpus cerebellum were noted. The proliferative activity in regional neurogenic niches is increased after injury of cerebellum. The maximal number of apoptotic elements in the cerebellum was observed in zones of the radial cell migration. We suggest that in damaged cerebellum both adult born cells and cells formed as a result of the reparative neurogenesis can be eliminated during radial migration as result of natural morphogenetic processes. Patterns of tangential and radial migration of cells were observed near the area of injury. The highest rate of apoptosis index was detected in the dorsal matrix zone corresponding to the zone of secondary neurogenesis. This testifies to the elimination of the newly formed cells at the stage of their localization in the matrix zones. The intensity of the apoptotic response varies in different areas of O. masou cerebellum.