The Relationship of Cell Cycle Phases and Embryonic Development of Bothrops Snakes

Author(s): Corrêa PG, Maria DA

Squamatas are the only strain of reptiles with species that give birth to free- living neonates (viviparity), capable of living independently of extraembryonic tissues. In many Viperidae species reproduction is seasonal, but not all females reproduce in a given year. Intra and interspecific variations also occur in relation to mating and follicular activity, thus allowing hormonal changes responsible for physiological events. The routine deposit of infertile and abnormal eggs in both oviparous and viviparous Squamata species is routinely reported. Follicular atresia is a hormonally controlled degenerative process by which ovarian follicles, at various stages of development and growth, of mammalian and non- mammalian vertebrates lose their integrity and are eliminated before ovulation. Apoptosis, a fundamental mechanism for germinal cell removal, a highly regulated and highly efficient cell death program. In order to monitor and investigate the high number of atretic eggs released by captive Bothrops snakes, we investigated possible apoptotic cell death studing cell cycle as a molecular approaches. Different cell cycle phases were identified in the embryos of captive Bothrops snakes. In Gate-1 the cells were mostly in division (Mitosis) than Gate-2. In both gates the cells are in phase S, synthesizing proteins and DNA to divide. The atretic eggs showed different stages of development, differentiation and maturation, and that cells were involved in the organogenesis of these snake species. The hypothesis from: "Is atretic egg fertilized?" to atretic egg. In this study was confirmed by the identification of germinal disks in different stages of organogenesis, which expressed different stages of growth kinetics and cell differentiation. Oxidative stress can modulate cell development in cell division leading to cell fragmentation and cell death.