Apoptosis of somatic cells in follicules and the functional status of bos taurus oocytes

Abstract

In the present study, the analysis of apoptotic changes in the somatic cells of the follicle (granulosa and cumulus), depending on the diameter of the follicle (<3 mm, 3-5 mm, 6-8 mm) and the functional status of the oocyte (growing oocytes or oocytes that have finished growth phase) is presented. The functional status of the oocytes was assessed by BCB test based on the difference in the color of the ooplasm after exposure by the vital dye of brilliant cresyl blue (BCB)..Apoptosis in granulosa and cumulus cells isolated from follicles containing growing oocytes or oocytes that have finished growth phase was determined by the TUNEL (Feng W., Pan Zhifang Z. 2014).It is shown that granulosa from Bos Taurus folliclesare characterized by different levels of apoptosis depending on the status of oocytes (growing oocytes or oocytes that have finished growth phase), isolated from these follicles.The proportion of apoptotic granulosa cells in follicles containing the oocytes that have finishedgrowth phase, regardless of diameter of the follicle, was significantly higher than in follicles containing growing oocytes. In cumulus cells, on the contrary, there is no such trend. The level of apoptotic in the cumulus cells of oocytes in a different functional state did not have significantdifferences in all experimental groups. This data allow us to assess the level of apoptosis in granulosa of ovarian follicles as an indicator of the functional status of the developing oocyte and suggest to use this indicator as prediction of the quality of donor’s Bos Taurus oocytes