Possible modulators of IL-8 and GRO-alpha production by granulosa cells.

Abstract

Interleukin-8 (IL-8) and growth-regulated oncogene-alpha (GRO-alpha) have been proved to be important modulators of leukocyte chemotaxis in the mechanism of human ovulation. This study investigated the possible effects of IL-1alpha, tumor necrosis factor-alpha (TNF-alpha), protein kinase C (PKC) activators (TPA), and db-cyclic adenosine monophosphate (cAMP) on IL-8 and GRO-alpha production by immortalized GC1a and granulosa-lutein cells. Confluent granulosa-lutein cells were placed in serum-free medium before incubated for 8 hr with the above-mentioned test agents. Finally, we measured IL-8 and GRO-alpha levels in the culture media using an enzyme-linked immunosorbent assay (ELISA). Treatment of granulosa-lutein cells with of IL-1alpha (1 nM), TNF-alpha (1 nM), TPA (1 nM) and db-cAMP (100 microM) produced higher levels of IL-8 than untreated cells by 8 hr (2274.7 +/- 146.3, 1489.8 +/- 190.1, 1452.9 +/- 152.7, 1313.6 +/- 48.4 pg/mL, respectively; control = 457.7 +/- 38.2 pg/mL; P < 0.001). Treatment of granulosa-lutein cells with 1 nM of IL-1alpha, TNFalpha, TPA, and db-cAMP (100 microM) resulted in higher levels of GRO-alpha than untreated cells by 8 hr (993.7 +/- 9.5, 171.4 +/- 6.5, 147.5 +/- 6.7, 472.4 +/- 16.2 pg/mL respectively; control = 73.8 +/- 8.2 pg/mL; P < 0.001). Our data strongly suggests roles for IL-1alpha, TNFalpha, and PKC activators in the inflammation-like mechanism of human ovulation. Furthermore, our study suggests a positive, but still debatable, role for cAMP in the same mechanism.