Expression of peroxisome proliferator activated receptor (PPAR) genes in porcine endometrium exposed in vitro to IL-6 and INFγ.

The aim of the present study was to examine the effects of interferon gamma (INFγ) or interleukin 6 (IL-6) on gene expression of PPARs in the porcine endometrium on day 14 of the estrous cycle and pregnancy. Endometrial tissue (200-210 mg), after 18 h of pre-incubation, was incubated for 6 or 12 h in the presence of INFγ (5 or 50 ng/ml) or IL-6 (1 or 10 ng/ml). Gene expression was analyzed by quantitative real time RT-PCR. During the estrous cycle, neither INFγ nor IL-6 affected PPARα and PPARβ/δ transcript levels in the endometrium of the cyclic pigs incubated for 6 or 12 hours. The presence of INFγ (5 ng/ml) significantly (p<0.05) increased PPARγ1 gene expression in the tissue incubated for 12 h. During pregnancy, INFγ (50 ng/ml) significantly (p<0.05) enhanced PPARα and PPARβ/δ mRNA levels in the endometrium incubated for 6 h, whereas IL-6 (1 or 10 ng/ml) did not change their expression at any incubation time. The effect of both cytokines on PPARγ1 transcript level differed and was dependent on the incubation time. We observed an inhibitory (after 6 h of incubation, p<0.0001) and a stimulatory (after 12 h of incubation, p<0.05) effect of INFγ (5 ng/ml) or IL-6 (10 ng/ml) on PPARγ1 gene expression. The present study indicates that INFγ and IL-6 modulate PPARs gene expression in the porcine endometrium during the estrous cycle and pregnancy. The effect depends on the reproductive status of animals and the length of in vitro incubation of endometrial tissue with the treatments.