Evaluation of apoptosis as a mechanism of follicular cell atresia in the ovaries of cattle (bos indicus) and buffalo (bubalus bubalis) fetuses
S.S.D. Santos, M.A.P. Ferreira, R.V. Sampaio, N.N. Costa, D.C.N. Santos, P.P.B. Santana, A.L.A. Sá, B.B. Silva, M.S. Cordeiro, T.V.G. Silva, M.S. Miranda, O.M. Ohashi
Anim Reprod, vol.10, n1, p.55-61, 2013
The objective of this study was to investigate the occurrence of apoptosis in the ovaries of cattle and buffalo fetuses between 4 and 8 months old by the terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling (TUNEL) assay. Histological analysis of the ovarian tissue showed that apoptosis occurred at all ages evaluated, presenting a similar pattern among different fetal stages in both species. Within species, secondary follicles displayed a higher (P < 0.05) mean number of apoptotic follicular cells than primordial or primary follicles in cattle. In buffalo there was a similar number (P > 0.05) of apoptotic follicular cells among the three follicular classes compared. Comparing results between species, secondary follicles had a higher (P < 0.05) mean number of TUNEL positive cells in bovine fetuses; however, this difference was proportional to the larger number of follicular cells present in secondary follicles in this species. In summary, the TUNEL method was effective for the detection of apoptosis in the supporting cells of ovarian follicles from bovine and buffalo fetuses with apoptosis occurring at similar rates in both species between 4 and 8 months of gestational age. Further studies are needed to better understand the dynamics of apoptosis as a regulator of follicular atresia in fetal ovaries from these species, as well as the potential involvement of the oocyte in this process.
apoptosis, buffalo, cattle, ovarian development, TUNEL