Effects of Growth Hormone on In Situ Culture of Bovine Preantral Follicles are Dose Dependent.

Abstract

The objective of this study was to evaluate different concentrations of growth hormone (GH) on the development of bovine preantral follicles cultured included in the ovarian tissue (insitu) on the rates of morphologically normal, viable, primordial and developing follicles, as well as the oocyte and follicle diameter and ultrastructural analysis. Ovarian fragments collected from cows with no cross-breeds defined were cultured insitu for 1 and 7days in minimal essential medium (α-MEM+) supplemented with different concentrations of recombinant human GH (0, 10, 25, 50ng/ml). The ovarian fragments non-cultured (control) and cultured were processed for classic histology, mechanical isolation and electron transmission microscopy (MET). The parameters underwent anova (Tukey's and Dunnett's tests) and chi-square test (χ(2) ). After 7days of culture, the treatment with 50ng/ml GH showed no differences with fresh control (p>0.05) and had greater effectiveness than in the 0, 10 and 25ng/ml GH concentrations of the morphologically normal follicles. Regarding the primordial follicles, a reduction was observed in the 50ng/ml GH concentration concomitant with the significant increase in developing follicles, differing from both the fresh control and the other GH concentrations tested. In addition, 50ng/ml GH showed a larger follicle and oocyte diameter when compared to the other treatments cultured. Similar structures were ultrastructurally observed in the control group, 50ng/ml GH. Follicles cultured in 10ng/ml GH showed nuclear invagination, vacuoles and lesioned basal membrane. Hence, it is concluded that 50ng/ml GH is the most effective concentration for the development of preantral follicles cultured insitu.