Background: TNF- has a wide range of functions in processes
within the ovaries, including follicular development, ovarian hormones synthesis,
ovulation, granulosa cell necroptosis, and follicular atresia. Innate immune
response in the ovaries is the main source of TNF-. The purpose of this
study is to explore the dose- and time-dependent interactions between
TNF- and human granulosa cells. Methods: The follicular fluids
(FF) were obtained from infertile patients undergoing IVF with PCOS (n = 20) and
healthy women (n = 19). Granulosa cells were cultured and treated with varying
concentration of recombinant human TNF-. Cell viability was detected by
CCK-8 method, the levels of TNF-, estradiol, and inhibin were measured
with ELISA, and cell apoptosis was detected by flow cytometry. Q-PCR and
western-blot were used to evaluate the expression of TNFR1/2, P450, Inhibin
/A, and caspase 3. Results: The level of
TNF- increased gradually with the development of follicles and was
remarkably higher in the FF of PCOS patients than in that of healthy women.
Treatment with TNF- as low as 0.2 ng/mL promoted the proliferation of
granulosa cells, thus upregulating P450 aromatase and inhibin A. On the other
hand, a high concentration of TNF- (0.4, 0.8, 2, and 8 ng/mL) showed
dose- and time-dependent inhibitory effects on cell viability and E2 and inhibin
A secretion. However, no marked differences in the expression of the two types of
TNFR were observed in TNF--treated granulosa cells.
Conclusions: The data presented here verify a biphasic effect of
TNF- on human ovarian endocrine and follicular development.