Messenger RNA and protein expression of tumor necrosis factor α and its receptors in human follicular granulosa cells

To evaluate the concentration of tumor necrosis factor alpha (TNF-alpha) and its soluble receptors (sTNFR I and II) in serum and follicular fluid (FF) at the time of oocyte retrieval and to detect expression of TNF-alpha and its receptors by luteinized granulosa cells (GCs). In a cross-sectional study and through an in vitro fertilization-intracytoplasmic sperm injection (IVF-ICSI) program, 81 women undergoing oocyte retrieval were recruited. Serum and FF were obtained from 81 women. GCs were pooled from 20 patients (from six different days of oocyte retrievals, 5-16 follicles per patient). TNF-alpha and its soluble receptors concentration were determined by enzyme-linked immunosorbent assay and also their expression by immune cytochemistry and reverse-transcription polymerase chain reaction analysis. The median TNF-alpha concentration in serum was 4.06pg/ml (interquartile range [IQR], 3.71-6.14) and significantly higher than that in FF with 3.50pg/ml (IQR, 3.05-5.01), p<0.001. The sTNFR I and II levels in serum were lower and higher than FF, respectively. The TNF-alpha levels in serum and FF of good responders were higher than low responders (p=0.017 and 0.021, respectively). TNF-alpha cut-off level for low responders versus good responders was 4.174pg/ml in serum with a pregnancy rate of 25.8% and 40% for below and above of this level, respectively (p=0.19). For FF, the cut-off value was 3.89pg/ml. TNF-alpha and its receptors were expressed by GCs. The presence of TNF-alpha and its soluble receptors in serum and FF and their expression by GCs suggest an important role for this cytokine in ovarian function.