Effect of Astragalus injection on expression of calmodulin after hypoxia/hypoglycemia and reoxygenation in rat hippocampal neurons

AIM: To investigate the effect of Astragalus injection on the expression of calmodulin(CaM) after hypoxia/ hypoglycemia and reoxygenation in rat hippocampal neurons.METHODS: The hippocampal neurons were cultured for 8 days and divided into 4 groups: normal control group (normal control), hypoxia/hypoglycemia and reoxygenation group (model), Astragalus injection solution group (solution control) and Astragalus injection group ( Astragalus ).The cells in all groups were treated with reoxygenation and normal medium after deprived of oxygen and glucose for 30 min except normal control group.The method of immunohistochemistry was used to measure the number of caspase-3 positive neurons.The expression of CaM at mRNA and protein levels was measured at time points of 0 h, 0.5 h, 2 h, 6 h, 24 h, 48 h, 72 h and 120 h after hypoxia/hypoglycemia and reoxygenation by RT-PCR and Western blotting, respectively.RESULTS: No difference of the parameters at all time points between model group and solution control group was found.Compared with normal control group, the numbers and the percentages of caspase-3 positive cells at all time points obviously increased in model group except at 0 h and 0.5 h (P<0.05).Compared with model group, the numbers and the percentages of caspase-3 positive cells were decreased in Astragalus injection group except at 0 h and 0.5 h (P<0.05).Compared with normal control group, the protein expression of CaM in rat hippocampal neurons at all time points obviously increased in model group (P<0.05).However, the protein expression of CaM in rat hippocampal neurons at all time points obviously decreased in Astragalus injection group as compared with model group (P<0.05).Compared with normal control group, the mRNA expression of CaM in rat hippocampal neurons at all time points obviously decreased in model group (P<0.05).The mRNA expression of CaM in rat hippocampal neurons at all time points obviously increased in Astragalus injection group as compared with model group (P<0.05).CONCLUSION: Astragalus injection inhibits the protein expression of CaM, the calcium overload and the expression of caspase-3 after hypoxia/hypoglycemia and reoxygenation, thus inhibiting hippocampal neuronal apoptosis.