Effects Of Maternal Limb Ischemic Preconditioning On Fetal Hippocampal Neurons Apoptosis Induced By Intrauterine Distress-reoxygenation In Rats

Object: To evaluate the influence of maternal limb ischemic preconditioning onfetal hippocampal neurons apoptosis induced by intrauterine distress-reoxygenation inrats.Methods: Timed-pregnant Sprague Dawley (SD) rats were anesthetized andunderwent laparotomy on embryonic Day19.Intrauterine ischemia was induced byclamping the uterine and uterine branch of the ovarian blood vessels with aneurysmclamps for a period of15min followed by removal of the clamps to permitreperfusion. At the same time, limb ischemic preconditioning in the pregnant wasgenerated by5min occlusion followed with the same period of reperfusion of theright hind femoral artery, and repeated for three cycles.12pregnant rats wererandomly assigned to4groups: sham (S) group,control (LIP)group,fetal distress (FD)group and to receive LIP underwent Intrauterine distress (LIP+FD) group.Cesareansection birth occurred on embryonic Day21to aquire6rat fetal alive in each group.The pups were decapitated and the pyramidal cells in pups CA1hippocampus weremeasured through light microscope.Neuron apoptosis and the influence of LIP onapoptosis was detected by terminal deoxynucleotidyl transferase-mediateddUTP-biotin nick end labeling (TUNEL) staining. The expression of bcl-2and baxwere detected by immunohistochemical method.The rate of neural apoptosis andbcl-2/bax were calculated. Result: The rates of neural apoptosis in group(FD, LIP+FD) were significantly higherthan that of group S (P<0.05), while with no significant differences of groups S andgroups LIP (P>0.05). The expression of bcl-2in group FD were significantly lowerthan that in group S (P<0.05), while with no significant differences of groups S andgroups LIP (P>0.05). But they were significantly higher(P<0.05) in group LIP thanthat in groups S. Compared with group FD, the rates of neural apoptosis weresignificantly lower (P<0.05), while the expression of bcl-2and the rates of bcl-2/baxwere significantly higher(P<0.05) in group LIP+FD. Conclusions: Maternal limbischemic preconditioning ameliorates fetal hippocampal neurons apoptosis induced byintrauterine distress-reoxygenation in rats,which maybe associated with up-regulationexpression of bcl-2.