Processes of Proliferation and Apoptosis in the Brain of the Amur Sturgeon

Abstract

Using techniques of immunoperoxidase staining of proliferating cell nuclear antigen (PCNA) and TUNEL labeling of fragmented DNA, we studied sites of proliferation and apoptosis in the myelencephalon, cerebellum, tectum opticum, thalamus, and hypothalamus of the Amur sturgeon (Acipenser schrenckii). We found that the processes of proliferation and apoptosis are maintained in the brain of 3-year-old sturgeon individuals; the ratio of these processes in different cerebral regions varied significantly. The maximum intensity of proliferative activity was found in the periventricular zone of the myelencephalon (proliferation index, on average, 21.0 ± 1.3%). This fact allows us to consider this cerebral region a most important zone were adult neurogenesis occurs in the sturgeon. In the medial reticular formation, dorsal thalamic nuclei, inner fibrous layer of the tectum, and lateral hypothalamus, the maximum numbers of apoptotic elements were found. Therefore, these zones in the brain of the sturgeon correspond, apparently, to the regions where postmitotic neuroblasts are localized. In sensory centers (tectum and nuclei of the V, VII, and X nerves), significantly varying ratios of intensities of proliferation and apoptosis were found; this is indicative of dissimilar rates of growth and differentiation in visual and chemosensory centers of the sturgeon brain. The high proliferative activity in sensory and motor cerebral centers of the sturgeon allows us to hypothesize that a neotenic pattern is preserved in these CNS regions of adult sturgeons over a long period after the embryogenesis has been completed.

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

“…The process of apoptotic cell death is a physiological response of the CNS of O. masou after damaging impact on the cerebellum. However, it is necessary to consider that the phenomenon of apoptosis is characteristic also for morphogenetic processes during a post-embryonic development of a brain of fishes [16,17].…”

“…Such material is defective from the point of view of diploidic quantity of chromosomes and usually it gets eliminated via apoptosis [16]. In study of adult individuals of the Amur sturgeon, existence of high apoptotic indices in different parts of the central nervous system, including integrative centers (optic tectum, cerebellum) and sensory centers (nuclei of V, VII and VII craniocereberal nerves) of a medulla oblongata was revealed [17]. These properties are characteristic of the proceeding morphogenetic activity of different brain centers, which continue to grow throughout the animal's life.…”

DNA methylation patterns in the round goby hypothalamus support an on-the-spot decision scenario for territorial behaviour

“…Zones of proliferation and apoptosis have been described [91,92], also in the context of reproduction [93]. Teleost brain plasticity may therefore have an impact on global methylation patterns in the inferior lobes.…”

Adult and Reparative Neurogenesis in Fish Brain

“…The process of apoptotic cell death accompanies the "normal" adult neurogenesis [35], and, at the same time, it is a physiological response of the nervous system to injury of O. masou cerebellum. Apoptosis during normal development has been described in the brain of A. leptorhynchus [27].…”

“…This material is obviously defective, because the relevant units do not have a normal diploid number of chromosomes, and is subject to elimination of apoptotic scenario [36]. In studies on intact adult specimens of Amur sturgeon have been found high values of apoptotic index in different parts of the central nervous system, including the integrative centers of brain (optic tectum, cerebellum) and sensory centers of the brain stem (nucleus V and VII cranial nerves pairs) [35]. Similar phenomena are typical for continuing morphogenetic activity in the various centers of the brain of fish, where continued replenishment of new cells occurs throughout life.…”