OBJECTIVEThere was consanguineous relationship between caspase-3 and early damage after hypoxia and ischemia. Caspase-3 plays a key role in the process of apoptosis in neuron. Magnesium sulfate could protect neuron from injuries, but the mechanism was not clear. The study was to investigate the expression of caspase-3 mRNA in the hippocampus of seven-day-old hypoxic-ischemic rats and the possible mechanism of neural protection with magnesium sulfate.

METHODSThe model of seven-day-old hypoxia-ischemia rats was established. The rats were divided randomly into 6 groups as follows: (1) normal control (n = 4); (2) sham surgery control (n = 4); (3) hypoxia-ischemia (n = 4); (4) sodium chloride injection with hypoxia-ischemia (n = 4); (5) magnesium sulfate pre-injection with hypoxia-ischemia (n = 4); (6)magnesium sulfate post-injection with hypoxia-ischemia (n = 4). The therapy groups received a bolus injection of 500 mg/kg magnesium sulfate intraperitoneally 0.5 hour before or after hypoxia-ischemia. Semi-quantitative RT-PCR was used to measure caspase-3 mRNA expression in the hippocampus 24 hours after hypoxia-ischemia.

RESULTSThe expression of caspase-3 mRNA was significantly increased in the hippocampus of the hypoxia-ischemia pups (1.88 +/- 0.36 vs 0.97 +/- 0.46, P < 0.05). The expression of caspase-3 mRNA in rats with magnesium sulfate pre-injection and post-injection decreased significantly (1.54 +/- 0.49, 1.65 +/- 0.48 vs 1.88 +/- 0.36, P < 0.05).

CONCLUSIONCaspase-3 was activated in the hippocampus of the seven-day-old rats 24 hours after hypoxia-ischemia. The suppression of the expression of caspase-3 mRNA in the hippocampus was probably related to the protective effect of magnesium sulfate on the brain injury of hypoxia-ischemia.