Endocrine Abstracts

The regulation of TNF-α and IL-6 secretion in LPS-stimulated Peritubular cells was investigated in vitro. Immature rat Peritubular cells were incubated with LPS (10 μg/ml) over 24 h culture. TNF-α and IL-6 were measured in the culture medium by ELISA at 24 h, TNF-α and IL-6 genes by real-time RT-PCR, and activation of NF-κB, MAPKs, and AP-1 signal transduction pathways by western blotting. LPS stimulated the mRNA expression of IL-6 and much more the expression of TNF-α (148-fold). In the presence of trichostatin-A (histone deaceytylase inhibitor), the mRNA expression of IL-6 but not TNF-α was potentiated, even when no detectable expression was observed in the TSA-alone treated cells. The degradation of IκBα was noticed at 30 min and then regains stable expressions afterwards. This corresponded with increased expressions of p-p38, NF-κB (p65) and p-JNK at the 30 min culture period. LPS also stimulated the secretion of IL-6, and there was no synergistic effect by TSA on IL-6 production. In contrast to IL-6, no detection of TNF-α was noticed in PTCs after LPS stimulation. These results suggest that the IκBα, MAPKs, and AP-1 signalling cascades are active in PTCs, and therefore, the immunosuppressive capacity of PTCs is compromised during LPS-induced testicular inflammation resulting to the increased secretion of IL-6.