外源性端粒酶逆转录酶基因转染对新生大鼠缺氧缺血性脑损伤的神经保护作用

The neuroprotective role of exogenous TERT gene in neonatal rats with hypoxic-ischemic brain damage

摘要:

目的 探讨端粒酶逆转录酶（TERT）对新生大鼠缺氧缺血性脑损伤（HIBD）后细胞凋亡的影响。方法 将72只新生大鼠分为假手术组、空质粒组、HIBD组和TERT组。用改良Rice法制备新生大鼠HIBD模型。采用苏木精-伊红染色法观察脑组织病理改变。空质粒组和TERT组分别于术后0.5 h，经侧脑室注射pcDNA3.1空质粒或TERT真核表达质粒pcDNA3.1-TERT。采用Western blot法检测各组大鼠脑组织TERT、凋亡诱导因子（AIF）和活化型半胱氨酸蛋白酶3（CC3）的蛋白表达水平；采用TUNEL法检测各组神经细胞凋亡情况。结果 与假手术组相比，HIBD组、空质粒组和TERT组大脑皮层中TERT蛋白表达增加（P < 0.01）；与空质粒组和HIBD组相比，TERT组TERT蛋白表达明显增加（P < 0.01）。与假手术组相比，空质粒组和HIBD组AIF和CC3蛋白表达、细胞凋亡指数均显著增加（P < 0.01）；与空质粒组和HIBD组相比，TERT组AIF和CC3蛋白表达、细胞凋亡指数均明显减少（P < 0.01）。结论 TERT可抑制缺氧缺血诱导的神经细胞凋亡，在新生大鼠HIBD中具有一定的神经保护作用。

Abstract:

Objective To study the effect of telomerase reverse transcriptase (TERT) on cell apoptosis in neonatal rat brains after hypoxic-ischemic brain injury (HIBD). Methods A total of 72 neonatal rats were divided into sham, vehicle, HIBD and TERT groups. HIBD was induced by Rice method in the later three groups. The neonatal rats in the vehicle and TERT groups were injected with plasmids containing mock or full length TERT by an intracerebroventricular injection 30 minutes after hypoxic-ischemic (HI) injury. Pathological changes of brain tissue were observed by hematoxylin and eosin (HE) staining. Western blot was used to detect the protein expression of TERT, apoptosis-inducing factor (AIF) and cleaved caspase 3 (CC3). Apoptotic cells were detected by TUNEL staining. Results Western blot showed that TERT protein was dramatically increased in the vehicle, HIBD and TERT groups compared with the sham group. Compared with the vehicle and HIBD groups, TERT protein in the TERT group was significantly upregulated. Compared with the sham group, there was a significant increase in apoptotic index and expression of AIF and CC3 proteins in the vehicle and HIBD groups (P < 0.01). The TERT group showed decreased expression of AIF and CC3 proteins and apoptotic index compared with the vehicle and HIBD groups (P < 0.01). Conclusions TERT can inhibit cell apoptosis induced by HI and might have a neuroprotective role in developing brain with HIBD.