The Effect Of HCG On IL-1, IL-6 And IL-8 Production In PBMC

Objective To test the regulatory effect of HCG on the gene expression of cytokines(IL-l and IL-6) that initiate inflammatory reaction protected against bacteria and the production of neutrophil chemokine(IL-8) and to probe the immune mechanism of immune-endocrine interactions in body.Methods Human PBMC were cultured with LPS(22 μg/ml) and different doses of HCG(100, 50, 25, 12.5, 6.25, 3.125 U/ml) at 37 ℃, 5 %CO₂ for 4 hrs, mRNA of cells harvested were isolated, then RT-PCR was performed with primer of IL-1 and IL-6 separately. The PCR products were quantitated and analyzed. PBMC were isolated from nonpregnant and pregnant women, and induced by recombinant HCG in different concentrations. ELISA was used to measure the level of IL-8 and RT-PCR was used to test IL-8 mRNA expression.Results HCG in a dose range of 25 12. 5 U/ml have significantly suppressive effect on both IL-1 and IL-6 mRNA expression (P < 0. 01). There were no impact on IL-1 and IL-6 mRNA expression in the groups in which the HCG dose was higher than 25 U/ml and lower than 12.5 U/ml. The IL-8 production by PBMC obtained from women at 4 and 5 wk gestation was significantly higher than that by PBMC obtained from nonpregnant women, pregnant women at 6-11 wk gestation, pregnant women at 4-6 month gestation and pregnant women at 7-9 month gestation. When PBMC culture medium obtained from health nonpregnant women added r-HCG at concentrations of 25U/ml, a significant enhancement of IL-8 production was observed. No significant increase of IL-8 production was observed at concentrations of 12.5U/ml or less. A small amount of production of IL-8 was observed from 1 hafter r-HCG(25U/ml) administration. After 3h, a clear increase of IL-8 production was detected, and the concentration continued to increase until at least 24h. IL-8 mRNA expression was detected 30 min after r-HCG administration (25U/ml). Increased expression of the mRNA was observed until 12 h, and this expression then decreased and disappeared by 48 h.Conclusion HCG range from (25^<sup>12. 5 U/ml) inhibites the gene expression of cytokines(IL-l and IL-6) that initiate inflammatory reaction protected against bacteria and stimulates PBMC obtained from nonpregnant women to product IL-8. This indicates that HCG existence in normal human may take part in the production of the cytokines that initiate inflammatory reaction and neutrophil chemokine, and HCG may play a role of in promoting and resisting inflammation in body.