Influence of Ca2+ on the phosphorylation of CREB, and the relationship between Pª²CREB and apoptotic neurons in neonatal rats after hypoxicª²ischemia

    LI Wenª²Lian, WANG Ling, ZHANG Hongª²Ai

    Department of Paediatrics, Tangdu Hospital, Fourth Military Medical University, Xi¡¯an 710038, China

    ¡¾Abstract¡¿ AIM: To explore the influence of Ca2+ on the phosphorylation of CREB and apoptosis of neurons in the neonatal rats brain after hypoxicª²ischemia (HI) so as to offer some theoretical basis for the therapy of HIBD in clinic. METHODS: Seven days old SD rats (n=126) were randomly divided into three groups: the sham control group; the HI group; the Ca2+ antagonist+HI group (intervention group). In the HI group and the intervention groups, the right common carotid artery was temporarily occluded for 2 h by No. 0 thread, then exposed to 80 mL/L oxygen and 920 mL/L nitrogen gas mixture for 2 h. In the intervention group, Nimodinpine was injected into the abdominal cavity before and after HI respectively. At different periods after HI, the expression of Pª²CREB in different groups was detected by immunohistochemical methods. The apoptotic neurons in different groups was detected by Turnel method. RESULTS£º In the HI group, the expression of Pª²CREB in the right hippocampus was much higher than that in the sham control group (P<0.01), and peaked 4 h after HI, and then continued to decrease. The number of apoptotic neurons in the right hippocampus was much higher than that in the sham control group (P<0.01), and pesked 48 h after HI, and then continued to decrease. In the intervention group, the expression of Pª²CREB has no difference with that in HI group (P>0.05). But the number of apoptotic neurons was much fewer than that in HI group (P<0.01). CONCLUSION: Ca2+ has no obvious influence on the phosphorylation of CREB; Ca2+ is involved in the damage of neurons during the period of post HI. Ca2+ antagonist(Nimodipine) can reduce this damage. ......