重复应用TGF-β1对缺氧缺血性新生大鼠的影响

Effects of repeated TGF-β1 on neonatal rats with hypoxic-ischemic brain damage

目的 探讨重复应用转化生长因子（TGF）-β1对缺氧缺血性脑损伤新生大鼠的影响.方法 95只不分性别的7日龄新生SD大鼠随机分为正常对照组、假手术组、模型组、处理组（生理盐水干预组及TGF-β1干预组）,模型成功后2h、10d,处理组腹腔注入10ng的生理盐水或TGF-β1,原位末端标记法和SP免疫组织化学方法,观察10d和40d后脑组织海马CA1区锥体细胞凋亡情况和Caspase-3表达.结果 建模后10d,与正常对照组和假手术组相比,TGF-β1治疗组海马CA1区锥体细胞凋亡存在（t=9.35,P〈0.05）,Caspase-3表达可见（t=7.43,P〈0.05）;与模型组和盐水干预组比较,细胞因子TGF-β1治疗组海马CA1区锥体细胞凋亡明显减少（t=5.63,P〈0.05）,Caspase-3表达减轻（t=4.55,P〈0.05）.建立模型后40d,与正常对照组和假手术组相比,模型组海马CA1区锥体细胞凋亡存在（t=7.25,P〈0.05）,Caspase-3表达可见（t=8.17,P〈0.05）,TGF-β1治疗组海马CA1区锥体细胞凋亡仍存在（t=6.07,P〈0.05）,Caspase-3表达可见（t=3.98,P〈0.05）.结论 新生大鼠脑缺氧缺血后应用TGF-β1具有明显的保护作用;单剂量应用TGF-β1可以保护神经元,重复应用TGF-β1未使保护神经元的作用得到延长;TGF-β1的作用可能是通过减少凋亡相关蛋白Caspase-3的表达起到作用的;该实验为细胞因子TGF-β1用于临床治疗缺氧缺血性脑损害提供了一些理论依据,并为TGF-β1治疗脑损伤机制的探讨提供了一定思路.

Objective To investigate the effects of TGF-β1 on neonatal rats with hypoxic-ischemic brain damage （HIBD）. Methods Ninety-five healthy unsexed 7-day-age SD neonatal rats were randomly divided into four groups, normal control （ NC ） group, sham operation group, hypoxic-ischemic （model） group, treated group （including saline-treated group and TGF-β1-treated group）. After the HIBD model was performed, treated group was injected with 10ng saline or TGF-β1 by abdominal cavity in 2 hours and 10 days. The pyramidal cell apoptosis and dynamic expression of Caspase-3 in brain tissue CA1 were examined in 10 days and 40 days with the methods of TUNEL and ElivisionTM plus immunohistochemistry. Results Ten days after HIBD, apoptasis of pyramidal cell（t = 9.35, P 〈 0.05 ） and expression of Caspase-3 （ t = 7.43, P 〈 0.05） existed in TGF-β1 treated group compared with NC group and sham operation group, while the apoptosis decreased（ t = 5.63 ,P 〈 0.05 ） and the expression of Caspase-3 reduced （t = 4.55, P 〈 0.05 ） compared with model group and saline-treated group. Forty days after HIBD, apoptosis of pyramidal cell existed （t = 7.25, P 〈 0.05） and expression of Caspase-3 （ t = 8.17 ,P 〈0.05）could be detected in model group, and the apoptosis still existed （t = 6.07 ,P 〈 0.05 ） and the expresstion of Caspase-3 could be found （t =3.98 ,P 〈0.05） in TGF-β1 treated group compased with NC group and sham operation group. Conclusion There are significant protective effects on neonatal rats with HIBD after TGF-β1 treatment. Single dosage of TGF-β1 can protect neuron, but repeated use of TGF-β1 doesn＇ t prolong the protective effects. TGF-β1 might act by depressing the expression of Caspase-3 which is related with apotosis. The experiment provides some theoretic basis for clinical use of TGF-β1 in treating HIBD, and offers a clue for future research on mechanism of TGF-β1 in treating brain damage.