3日龄未成熟大鼠慢性缺氧缺血脑损伤IGF-1及其受体的变化(英文)

Changes of IGF-1 and its receptor in 3-day-old premature rats with chronic hypoxic-ischemic brain damage

目的探讨胰岛素样生长因子-1(IGF-1)在3日龄未成熟大鼠慢性缺氧缺血脑损伤发病机制中的作用。方法90只3日龄SD未成熟大鼠随机分为对照组(n=40)和慢性缺氧缺血(HI,n=50)组。对照组仅切开颈部皮肤,HI组结扎双侧颈总动脉造成新生大鼠慢性缺氧缺血脑损伤,采用组织切片苏木素-伊红染色和免疫组化等方法,观察未成熟大鼠脑损伤时少突胶质细胞营养因子IGF-1和受体的表达、脑组织病理变化和白质细胞凋亡。结果3日龄未成熟大鼠慢性缺氧缺血脑损伤后IGF-1及其受体呈现动态变化。HI组在术后3～5d(生后6～8d)IGF1表达阳性的细胞减少,IGF-1受体表达却有增高趋势,变化以胼胝体和脑室周围白质部位明显,术后7～14d(生后10～17d)时逐渐恢复。同时脑白质出现液化疏松、脑室扩大等形态学病理变化,凋亡细胞计数在损伤后增多,以48h最为显著。结论提示IGF-1在3日龄未成熟大鼠慢性缺氧缺血脑损伤的发病机制中具有重要作用,为早产儿脑损伤的防治提供了实验依据。

Objective This study examined the expression of insulin-like growth factor-1(IGF-1)and its receptor in 3-day-old premature rats with chronic hypoxic ischemic brain damage (HIBD) and investigated the role of IGF-1 in the pathogenesis of this disease.Methods Ninety 3-day-old Sprague-Dawley rats were randomly assigned into a Control group (n =40) and a Hypoxic-ischemic group (HI, n = 50). HI was induced through bilateral common carotid artery ligation. The Control group was only sham-operated. Hematoxylin and eosin staining, TUNEL immunofluorescence staining and immunohistochemistry ways were used to investigate the expression of IGF-1 and its receptor, morphological changes of brain tissues and cell apoptosis of brain white matter. Results The expression of IGF-1 decreased in 3-5 days after HI, but that of its receptor increased in the HI group. The expression changes were most significant at corpus callosum and peri-ventricular white matter and recovered progressively in 7-14 days after HI. After 7 days of HI, the brain white matter presented with morphological changes such as rarefaction, liquefaction and lateral ventricular enlargement. Apoptotic cells in deep white matter increased after HI, and peaked at 48 hrs. Conclusions IGF-1 may play an important role in the pathogenesis of chronic HIBD in 3-day-old premature rats. This study provides an experimental basis for the prevention and treatment of HIBD in premature infants.