Growth differentiation factor 9 (GDF9) plays a key role in enhancing developmental competence and blastocyst yield during in vitro maturation (IVM). This study investigated whether GDF9 could counteract the harmful effects of lipopolysaccharide (LPS), a gram-negative bacterial component, on bovine in vitro embryo production, while also examining related gene expression in cumulus cells and oocytes. We hypothesized that GDF9 may compensate for LPS through the NF-κB pathway. Ovaries were collected from a slaughterhouse, and oocytes (≥ 50 per group per replicate) were matured under four conditions: control, GDF9, LPS, and GDF9 + LPS. After IVM, fertilization and culture were performed, with blastocyst development evaluated on Day 7. Cumulus cells and oocytes were analyzed for gene expression (RT-qPCR), while IVM media were tested for progesterone and estradiol. Results showed that co-treatment with GDF9 and LPS restored cumulus expansion, cleavage, blastocyst rate, and embryo quality compared with LPS alone (p < 0.05), with no differences from controls. LPS increased mRNA levels of CXCL8, TNFα, and TLR2 in cumulus cells (p < 0.05), but candidate gene expression in oocytes and cumulus cells remained unaffected. Steroid concentrations and estradiol:progesterone ratios were similar across groups. In summary, GDF9 supplementation alleviates LPS-induced impairment in bovine oocytes during IVM, though the underlying mechanisms remain unclear.
Scarlet et al. (Wed,) studied this question.