Role of granulosa cells in the achievement of meiotic competency and survivability of oocytes in rat Rattus norvegicus

Abstract

Meiotic cell cycle in mammalian oocyte is a protracted process that involves several stop newlineand go channels. It starts during fetal life and gets arrested at diplotene stage of first newlinemeiotic prophase. The diplotene arrest in oocyte may last for few weeks to several years newlineinside the follicular microenvironment depending upon mammalian species. The diplotene newlinearrest is the longest and imperative phase of meiotic cell cycle in which oocyte achieves newlinemeiotic competency. Achievement of meiotic competency in these oocytes starts with newlinemeiotic resumption from diplotene arrest, progression through metaphase-I (M-I) and ends newlinewith metaphase-II (M-II) stage by extruding first polar body (PB-I) at the time of newlineovulation. Encircling granulosa cells could release several signal molecules, which are newlinetransported to the oocyte via gap junctions to maintain meiotic arrest. The disruption of newlinegap junctions and interruption in cross talk between encircling granulosa cells and oocyte newlinemay deprive the oocytes from several signal molecules, growth factors and cell cycle newlineproteins that are required for the achievement of meiotic competency. Therefore, newlineidentification of key signal molecules within the cumulus oocyte complexes (COCs) will newlinebe instrumental in gaining deep insights into the intricate mechanisms underlying the newlineoocyte meiotic competence and uncovering novel regulators and reliable molecular newlinepredictors of oocyte quality. Hence the present Ph.D. research work aimed to determine newlinethe role of granulosa cells during the achievement of meiotic competency and survivability newlineof oocytes using rat as an experimental animal model. newline