PROBLEM: In granulosa cells, TLR4-mediated LPS-induced immune response interferes with ovarian granulosa cell function. METHOD OF STUDY: LPS-induced pro-inflammatory gene expression was monitored by real-time PCR and NF-κB was determined by the immuno-blotting and immuno-staining in granulosa cells in vitro. RESULTS: The LPS (1 μg/mL) increased pro-inflammatory gene expression which was reverted back by treatment with TLR4 signaling inhibitor. Cotreatment of CLA (10 μm) with LPS did not show any effect on LPS-induced pro-inflammatory gene expression but granulosa cells pre-treated with CLA for 24 hr, attenuated LPS-induced pro-inflammatory gene expression and nuclear NF-κB. GW9662, a PPARγ-inhibitor, further increased the expression of pro-inflammatory genes. CONCLUSION: The present findings reiterated that pre-treatment with CLA can prevent LPS-induced granulosa cells dysfunction.