Effects of tumour necrosis factor-alpha and interleukin-1 beta on in vitro development of bovine secondary follicles

The objective of this study was to determine the effects of TNF- and IL-1 on development and survival of bovine secondary follicle culture in vitro for 18days. Secondary follicles (0.2mm) were isolated from ovarian cortex and individually cultured at 38.5 degrees C, with 5% CO2 in air, for 18days, in TCM-199(+) alone (cultured control) or supplemented with 10ng/ml IL-1, 10ng/ml TNF- or both TNF- and IL-1. The effects of these treatments on growth, follicular survival, antrum formation, viability, ultrastructure and mRNA levels for GDF-9, c-MOS, H1foo and Cyclin B1 were evaluated. The results showed that addition of TNF- to culture medium increased follicular diameter and rate of antrum formation, whereas that of IL-1 and a mixture of IL-1 and TNF- did not do so. Ultrastructural analysis showed that, among the tested cytokine treatments, follicles cultured in the presence of TNF- had the best-preserved oocytes and granulosa cells. The presence of TNF-, IL-1 or both did not influence the expression of mRNAs analysed. In conclusion, in contrast to IL-1, TNF- promotes growth of and antrum formation in in vitro cultured bovine secondary follicles, while their ultrastructure and viability were maintained.