Cystathionine β-Synthase in the Brain of the Trout Oncorhynchus mykiss after Unilateral Eye Damage and in Conditions of in vitro Cultivation

Abstract

Expression of cystathionine β-synthase (CBS) in the brain of adult trout under normal conditions and 1 week after an eye injury was assessed using Western blot analysis. The study of CBS distribution in the brain of intact trout and after a mechanical eye injury in the telencephalon, tectum, cerebellum, and brainstem was carried out by the method of immunoperoxidase labeling on free-floating sections. The results of the study showed an increase in CBS expression in different brain divisions after an eye injury. In the visual projection center of the brain (tectum), radial glia cells expressing CBS were revealed after the injury. The emergence of CBS+ heterogeneous radial glia in the trout tectum after eye injury indicates the ability of the reactive neural stem cells (NSC) to synthesize hydrogen sulfide. CBS+ fibers and cells were found in the proliferative zones of cerebellum (valvula) and telencephalon (ventral region). In the intact trout tegmentum, CBS expression was observed in large neurons of the dorsal region and in the proliferative zones. After the eye injury, reactive neurogenic niches appeared in the brainstem, and no CBS-immunopositivity was detected in the periventricular zone. The increased expression of H₂S-producing CBS enzyme after a traumatic impact can probably be explained by the neuroprotective functions of hydrogen sulfide, which are implemented in the matrix zones of the brain associated with reparative neurogenesis. A cultivation of trout brain cells showed the formation of neurosphere-like complexes, a part of which exhibited CBS-immunopositivity in the monolayer.