The Effect of Gonadotropins and Cytokines on Human Luteal Cell Apoptosis

Kim, Min Joung; Hur, Soo Young; Lew, Young Oak; Kwon, Dong Jin; Kim, Jang Heub; Lee, Jin Woo; Lee, Weon Sun; Park, Sang Hi; Kim, Eun Jung

Abstract

OBJECTIVE
Our object is to evaluate the detailed mechanisms of support and regression of the human corpus luteum.
METHODS
To investigate the regulation of luteal function by gonadotropins, cytokines, and prostaglandins, the frequency of apoptosis and expression of Fas, Fas-L, Bcl-2, Bax, p53, caspase-8 were examined in cultured human luteal cells after treatment with various doses of FSH (30, 100, or 300 ng/mL), LH (30, 100, or 300 ng/mL), TGFbeta1 (1, 10, or 100 ng/mL), TNFalpha (1, 10, or 100 ng/mL), or PGF2alpha (1, 10, or 100 ng/mL) for 24 h. Cells were tested for apoptosis by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-digoxigenin nick end labeling TUNEL) method and cell death detection ELISA. Immunostaning was performed using anti-Fas, Fas ligand, Bcl-2, Bax, and p53 antibodies.
RESULTS
Incidence of apoptosis determined by TUNEL method in the group without treatment was 1.7+/-0.5% (0 h), 10.8+/-1.6% (24 h), and 12.9+/-1.2% (48 h), respectively. Spontaneous increase was significant at the latter time points. Significant suppression of incidence of apoptosis was observed with LH and TGFbeta1 (P<0.05). On the other hand, significant induction of incidence of apoptosis was observed with TNFalpha and PGF2alpha (P<0.05). Immunostaining revealed that p53 and Bax expressions after treatment with LH or TGFbeta1 were significantly lower than those without treatment. Bcl-2 and caspase-8 expressions were not significantly affected by any substance addition. Also we found that inductions of apoptosis by TNFalpha and PGF2alpha were not correlated with the expression of Fas, Fas ligand, Bcl-2, Bax, p53 and caspase-8.
CONCLUSION
Our results suggest that LH and TGFbeta1 may be involved in the support of luteal function via suppression of apoptosis, and that TNFalpha and PGF2alpha may contribute to luteal regression via its induction in human corpus luteum during early luteal phase. Also, Fas, Fas-L, Bax and p53 may play roles in this apoptosis controlled by LH, and TGFbeta1.