Effects Of Insulin Or Insulin-like Growth Factors On Apoptosis Of Human Trophoblast Cells Embryogenesis Of Early Pregnancy

Objective: To evaluate expression of insulin-like growth factors (IGFs) in villrs and serum IGF and investigate its effect to embryogenesis termination of early pregnancy. To investigate the potential role in preventing apoptosis of human trophoblast cells cultured in vitro from early pregnancy by different dosage of insulin, and to explore the mechanisms by inhabiting caspase-3 activity and by reducing Bcl-2 protein expression.Methods: Expression of IGF-1 and IGF- II was examined by immunohistochemical technique; the mRNAof IGF-1 and IGF- II was detected by flurorescent detection in situ hybridation (FISH); IGF-1 and IGF-II was determined by radioimmunoassay (RIA) in serum from pregnancy women just half and hour before artifical abortion. Human trophoblasts cells of early pregnancy were cultured in vitro and apatosis wasinduced by H2O2. Cells were divided into 3 groups: Normal control group; H2O2 treated group and H2O2 plus insulin treated group. The typical morphological changes of apoptotic cells were observed by electronic microscopy. Apoptotic rates were detected by flow cytometer. To observe the possible role of insulin, flow cytometer was used to detect Bcl-2 expression and caspase-3 activity was used to detect byspectrofluorometer.Results: Both the protein expression mRNA of IGF-1 and IGF- II were lower in the abnormal villus of embyogenesis termination than the normal villus of embryogenesis termination (P<0.01) and the serum lever of IGF- I and IGF-II in normal pregnancy woman were much higher than the abnormal pregnancy woman(P<0.01). After treatmented with H2O2 for 24h, typical morphological features of apoptotic cells were detected by electro microscopy. Insulin could markedly reduce H2O2-induced apoptotic rates of trophoblasts cells detected by flow cytometer. Bcl-2 expression rate of H2O2 treatd cells was lower than that of control cells(P<0.01), but caspase-3 activity was higher than that of control cells(P<0.01). Insulin could significantly upregulate Bcl-2 protein exoression and reduce caspase-3 activity in contrast with H2O2 group(P<0.01 ).Conclusion: IGF-I may play an important role in the regulation of fetal growth and placental growth and placental growth, the decrease of IGF-I and IGF-II levels may be the internal factors contributing to the tmbryogenesis termination of early pregnancy. Insulin could markedly inhibit H2O2-induced apoptosis of human trophoblasts cells. The underlying mechanisms may include inhibiting of caspase-3 activity and upregulation of Bcl-2 protein expression.