MK-801对新生大鼠脑缺氧缺血后Caspase-3激活及其对凋亡的影响

Effect of MK-801 on Caspase-3 Activation and Apoptosis after Cerebral Hypoxic-Ischemic Injury in Neonatal Rats

目的 探讨N 甲基 D 天冬氨酸 (NMDA)受体拮抗剂MK 80 1对新生大鼠缺氧缺血 (HI)后半胱天冬酶 3(Caspase 3)激活及凋亡的影响。 方法 7日龄新生大鼠在HI后即刻给予腹腔注射MK 80 10 .5mg/kg ,在HI后 2 4h取脑制作脑组织连续切片进行微管相关蛋白 2 (MAP 2 ) ,Caspase 3免疫组化染色及发夹寡核苷酸探针(HairpinProbe ,HPP)原位杂交 ,计算脑损伤面积及Caspase 3,HPP阳性细胞数。 结果 ①MK 80 1干预组脑损伤面积为 (2 3± 5 ) % ,较生理盐水对照组 (5 2± 12 ) %明显降低 ,P <0 .0 1;②MK 80 1干预组Caspase 3及HPP阳性细胞数 (6 5± 8) /高倍视野 ,(6 1.6± 11.5 ) /高倍视野 ,与对照组 (4 0± 6 .7) /高倍视野 ,(12 .6± 5 .2 ) /高倍视野相比均明显减少 ,其中HPP阳性细胞数减少比Caspase 3阳性细胞数减少更明显。 结论 MK 80 1能明显抑制Caspase 3的激活 ,减少神经元的凋亡 ,减轻缺氧缺血性脑损伤 (HIBD)的程度。

Objective To study the effect of MK 801, the antagonist of NMDA receptor, on caspase 3 activation and apoptosis after cerebral hypoxic ischemic injury in neonatal rats. Methods Seven day old rat pups were injected with either 0.5 mg/kg MK 801 or normal saline immediately after cerebral hypoxic ischemic injury (HI). The pups were killed 24 h after the injection. Brain damage was evaluated using MAP 2 immunostaining. Caspase 3 activation was examined using anti p17 subunit antibody. Apoptosis was examined by in situ labeling of hairpin probe (HPP). The infarction area was calculated according to MAP 2 staining. Active caspase 3 cells and HPP positive cells were counted in the MAP 2 negative area of the cortex. Results The infarction area was reduced from (52±12)% to (23±5)% after the treatment with MK 801. A few caspase 3 and HPP positive cells were also found in the cortex of normal rat brains. The number of positive cells reached a peak at 24 h after HI. Both the number of caspase 3 (from 65±8 to 40± 6.7 per high power visual field) and HPP (from 61.6 ± 11.5 to 12.6 ± 5.2 per high power visual field) positive cells were decreased after the treatment with MK 801. Conclusions MK 801 inhibits caspase 3 activation and reduces the number of apoptotic cells. NMDA is involved in the activation of the apoptotic process in the immature brain after HI.