异氟醚麻醉对新生大鼠齿状回神经干细胞增殖及分化的影响

Effects of isoflurane anesthesia on proliferation and differentiation of neural stem cells in the dentate gyrus of neonatal rats

目的探讨异氟醚麻醉对新生大鼠齿状回神经干细胞增殖及分化的影响。方法SD大鼠10只，7d龄，雌雄不拘，体重16～20g，采用随机数字表法，将其随机分为2组（n=5）：对照组（C组）和异氟醚组（I组）。Ⅰ组先吸入2．5％异氟醚3min行麻醉诱导，然后吸入1．5％异氟醚4h，C组只吸入空气。分别于给药前及停止给药后腹腔注射5-溴脱氧尿苷（Brdu）100mg／kg，以标记齿状回的神经干细胞及其子细胞，第2次给予BrdU后24h处死大鼠，取脑组织，采用BrdU和神经源性分化蛋白（NeuroD）（神经母细胞和未成熟神经元标志物）免疫荧光双标的方法测定BrdU＋和NeuroD＋表达情况，以BrdU＋细胞计数反映齿状回神经干细胞增殖情况，以NeuroD＋细胞计数与BrdU＋细胞计数的比值（NeuroD＋／BrdU＋）反映神经干细胞向神经元分化情况。结果与C组比较，Ⅰ组齿状回BrdU＋细胞计数减少，而齿状回NeuroD＋／BrdU＋升高（P〈0．05或0．01）。结论异氟醚麻醉可抑制新生大鼠齿状回神经干细胞的增殖，并促进其向神经元分化。

Objective To investigate the effects of isoflurane anesthesia on proliferation and differentiation of neural stem cells （NSCs） in the dentate gyrus of neonatal rats. Methods Ten SD rats, aged 7 days, weighing 16-20 g, were randomly divided into 2 groups （ n = 5 each） ： control group （group C） and isoflurane group （group I） . The rats in group I inhaled 2.5 % isoflurane for 3 rain for induction and then anesthesia was maintained with 1.5% isoflurane for 4 h, while the rats in group C only breathed the room air for 4 h. Bromodeoxyuridine （BrdU） 100 mg/kg was injected intraperitoneally right before the induction and after the end of administration to label NSCs and their progeny in the dentate gyrus. At 24 h after the 2nd administration of BrdU, double immunofluorescence for BrdU and NeuroD （a marker of neuroblasts and immature neurons） was used to assess NSC proliferation and neuronal differentiation. Results Compared with group C, the number of BrdU＋ cells in group I was significantly decreased, whereas the fraction of NeuroD＋/BrdU＋ differentiated cells was increased in the dentate gyrus（ P 〈 0.05 or 0.01 ）. Conclusion Isoflurane anesthesia suppresses the proliferation of NSCs and induces neuronal differentiation of NSCs in the dentate gyms of neonatal rats.