异氟烷单独或联合咪达唑仑对7日龄大鼠大脑caspase-3表达的影响

目的 观察异氟烷单独或联合咪达唑仑对7日龄大鼠大脑caspase-3表达的影响.方法 7日龄SD大鼠39只,随机分为对照组(C组,n=13),异氟烷组(I组,n=13)和咪达唑仑联合异氟烷组(MI组,n=13).C组:腹腔注射0.9%生理盐水10ml/kg,吸入30%O2 6 h;I组:在37℃恒温并通入1.5%异氟烷的麻醉小室内维持麻醉6h ;MI组:腹腔注射咪达唑仑9 mg/kg后,随即置于37℃恒温并通入1.5%异氟烷的麻醉小室内维持麻醉6h.麻醉结束即刻每组取3只大鼠,行动脉血气分析.麻醉结束2h 采用Realtime-PCR方法检测皮质和海马组织Caspase-3 mRNA水平的变化;并用免疫组织化学SABC法检测大脑Active caspase-3阳性神经细胞的分布情况,计数阳性细胞.结果 ⑴ I组和MI组大鼠麻醉结束即刻动脉血气分析结果与C组比较差异无统计学意义(P＞0.05).⑵ Realtime-PCR 结果显示,I组与MI组大鼠皮质和海马区Caspase-3 mRNA与对照组相比表达增多,且MI组与I组比较Caspase-3 mRNA表达增加(P<0.05).⑶免疫组化结果也显示:与对照组相比,I组与MI组大鼠在皮质、海马及丘脑部位Active caspase-3阳性神经细胞数量均明显增多 (P<0.05),而MI组与I组相比,在海马和丘脑部位Active caspase-3阳性神经细胞数量明显增多(P<0.05).结论 异氟烷麻醉能诱导脑发育高峰期大鼠重要脑区Caspase-3表达增加,联合应用咪达唑仑增加更明显;推测Caspase-3表达增加可能引起凋亡级联反应,导致神经细胞凋亡增加.

Effect of Isoflurane, Individually or Combined with Midazolam, on the Expression of Caspase-3 in Neural Cells of 7-day-old Rats

Objective To investigate the effect of isoflurane, individully or combined with midazolam on the expression of Caspase-3 in neural cells of 7-day-old rats. Methods Thirty-nine 7-day-old male and female SD rats were randomly divided into 3 groups （n=13 each）. Control group （C）： receiving intraperitoneal injection of 0.9 % saline for 6h of mock anesthesia; isoflurane group （I） ： receiving 1.5 % isoflurane exposure for 6h of anesthesia; midazolam isoflurane group （MI） ： receiving injection of 9mg/kg midazolam immediately before 1.5% isoflurane exposure for 6h anesthesia. At the end of anesthesia, 3 rats of each group were taken to collect 100μl artetial blood from the left cardiac ventricle to measure the values of pH, PaO2, PaCO2, BE, HCO3- and SaO2. 2 hours after the end of anesthesia, the expression of caspase-3 mRNA of the cortex and hippocampal were detected by real- -time PCR; and the expression of active caspase- 3 was detected by immunohistochemistry. Results （1） The values of pH, PaO2, PaCO2, BE, HCO3- and SaOz of I all groups shared no significant difference at the end of anesthesia. （2） The expression of caspase- 3 mRNA was up-regulated in I and MI groups in cortical and hippocampal areas（P〈0.05）. （3） Compared with those of the C group, the active caspase-3 positive cells were significantly increased in the I group and the MI group in the cortical, hippocampal and thalami areas （P〈0.05）. The number of cleaved caspase-3 postive cells was significantly increased in MI group as compared with that in I group in hippocampal and thalami areas, except for the cortical area. （P〈0.05）. Conclusion Exposure to isoflurane can elevate the expression of Caspase-3 in 7 -day-old rat brain, and its comhination with midazolam can trigger even higher erpression of Caspase-3.