Judging the degree of brain injury after hypoxia-ischemia in living neonatal mice in the early stage / 解剖学报

ABSTRACT

Objective To explore the method of distinguishing the degree of hypoxic-ischemic brain damage ( HIBD) in living mice in early stage, so as to lay a foundation for the follow-up study of the molecular mechanism of different degrees of HIBD. Methods The modified Rice-Vannucci method was used to duplicate the HIBD model of C57BL/6 J mice. On the 1 day and 3 days after the model, the scalp of mice were cut and the brain tissue were observed to distinguish between mild and severe lesions in living mice, and then 2,3, 5-triphenyltetrazolium chloride (TTC) staining, laser speckle cerebral blood flow imaging, HE staining, Fluoro-Jade B ( FJB ) staining and body weight difference before and after operation were used to verify the reliability of observation in living mice. Results Through the gross observation of brain tissue in living mice, HIBD could be divided into mild injury (HI-M) group and severe injury (HI-S) group. On day 1 and day 3 after HIBD, a significant decrease in cerebral blood flow, obvious gray infarction and a large number of necrotic neurons were observed in the HI-S group, and the body weight was significantly lower than that before operation. In the HI-M group, the cerebral blood flow of the injured side decreased only on the 3rd day after HIBD, and the loose arrangement of neurons in the cortex and hippocampus of the injured side was observed morphologically. The body weight was lower than that before operation. Conclusion Gross observation of brain tissue by cutting the scalp is a reliable method to distinguish mild and severe brain injury in the early stage of HIBD in living mice.