新生大鼠缺血缺氧性脑白质损伤脑组织形态学的动态演变

Dynamic Evolution Process of Brain Tissue Morphology in A Rat Model with Neonatal White Matter Damage Induced by Hypoxia-ischemia

目的建立新生大鼠缺血缺氧(HI)脑白质损伤模型,模拟早产儿HI脑白质损伤,阐明少突胶质细胞及髓鞘发育在脑组织HI中的动态演变过程。方法将3日龄新生大鼠随机分为HI组(n=40)和对照组(n=40),HI组结扎右侧颈总动脉后低氧2h(8%氧气);对照组不结扎仅分离右侧颈总动脉,也不给予低氧处理。实验后l、3、7、14、21 d分别检测体质量及脑质量的变化;HE染色观察脑组织形态学改变,透射电镜观察少突胶质细胞及髓鞘的超微结构变化。结果 HI组实验后3、7 d时体质量及脑质量的增长明显落后于对照组(P<0.01),14、21 d时HI组与对照组相比无明显差异(P>0.05);HE染色发现HI组实验后3 d时大量脑组织变性坏死形成小空洞,并通过透射电镜发现3、21 d时HI组少突胶质细胞坏死、髓鞘内小空泡形成及板层结构松懈。结论 HI致脑白质损伤后,新生大鼠生长发育延迟,少突胶质细胞及髓鞘发育障碍。

Objective To establish a hypoxia-ischemia （HI） rat model for neonatal white matter damage （WMD） and simulate WMD in premature infants, so as to observe the changes of morphology and ultrastructure in the brain tissues and clarify dynamic evolution process of the development of oligodendrocytes （OLs） and myelin in HI brain tissue. Methods Eighty newborn rats （ 3-day-old ） were randomly divided into HI group （ n = 40 ） and control group （n = 40）. Animals in the HI group were subjected to ligation of the right carotid artery, followed by 8% oxygen delivery for 2 h, while rats in the control group were only subjected to isolation of the right carotid artery, without exposure to hypoxia. The changes of body and brain weight were recorded on day 1,3,7,14 and 21, respectively. The changes of morphology in the brain tissues were observed by Hematoxylin and eo- sin （HE） staining, and the changes of ultrastructttre in OILs and myelin were also determined. Results The growth of body weight and brain weight of day 3,7 in HI group obviously lagged behind that of the control group （P 〈 0.01 ） ; there was no obvious ditierence at day 14 and day 21 between the HI group and control group （P 〉 0.05）. In HI group, the focus of necrosis was observed in a high number of cells of brain tissues, along with a cribriform change at day 3 by HE staining. OLs necrosis, myelin with a large number of small vacuoles and a loose structure were observed on day 3 and 21. Conclusion Rats with neonatal WMD grow slower than the control,and the development and maturation of OLs and myelin are impaired.