Ovarian IL-1α and IL-1β levels are associated with primary ovarian insufficiency

Primary ovarian insufficiency (POI) is characterized by premature ovarian failure and lack of menstrual periods in women under the age of 40. Ample evidence suggests that interleukin 1 (IL-1) family proteins are involved in the processes of ovarian follicular development and depletion. The association of these cytokines with POI disorder and the underlying molecular mechanism in regulation of the ovarian functions remain largely undetermined. In this study, follicular fluids and serum samples were harvested from POI patients and healthy women who underwent follicular aspiration during in vitro fertilization. Enzyme-linked immunosorbent assay (ELISA) and the quantitative real-time PCR (qPCR) were employed to assess the levels of protein secretion and mRNA expression of IL-1α and IL-1β, as well as the molecules that are critical for apoptotic pathways. Our results showed that IL-1α level in serum samples and follicular fluid of POI patients was significantly elevated in comparison to that in healthy women. Interestingly, the follicular levels of both IL-1α and IL-1β and TNF-α were significantly higher than their serum levels. Our qPCR analysis further revealed that there was a significant upregulation of apoptotic Bax mRNA expression, but expression of anti-apoptotic factor Bcl-2 mRNA expression was downregulated in POI patients. In conclusion, our studies revealed that the elevated level of IL-1 in follicle fluids of POI patients may be the major causal factor for follicular apoptosis that consequently impairs follicle reserve and ovarian functions by follicle depletion.