Association between blood lead levels and unfavorable IVF outcomes: potential involvement of endoplasmic reticulum stress response in granulosa cells.

Abstract

To investigate the relationship between blood lead levels (BLLs) and IVF clinical outcomes in infertile females and to further explore the possible involvement of granulosa cell (GC) endoplasmic reticulum (ER) stress in the process. One hundred twenty-three infertile women undergoing IVF cycles were included in the current study. All participants were divided into three (low, medium, and high) groups determined by BLL tertiles. Gonadotropin releasing hormone (GnRH) agonist regimen for ovarian stimulation was used for all patients, with follicular fluids being collected on the day of oocyte retrieval. Lactate dehydrogenase (LDH) levels in follicular fluid and the endoplasmic reticulum stress-signaling pathway of granulosa cells (GCs) were examined. The oocyte maturation rate and high-quality embryo rate on cleaved stage decreased significantly as BLL increased. For lead levels from low to high, live birth rate (68.29%, 56.10%, 39.02%; P=0.028) showed negative correlations with BLLs. Also, follicular fluid Pb level and LDH level was significantly higher in the high lead group versus the low group. Binomial regression analysis revealed significant negative correlation between BLLs and live birth rate (adjusted OR, 0.38; 95% CI, 0.15-0.95, P=0.038). Further analysis of the endoplasmic reticulum stress (ER stress) signaling pathway of GCs found that expressions of GRP78, total JNK, phosphorylated JNK, and CHOP increased and BCL-2 decreased with increasing BLLs. BLLs are negatively associated with final clinical outcomes in IVF patients that may be related to increased ER stress response and GC apoptosis. Thus, reducing Pb exposure before IVF procedures may improve final success rates.