Protective effects of activin A on brain tissue of neonatal rats with hypoxic ischemic brain damage

Objective: To investigate the preventive effects and possible mechanism of exogenous activin A(ACT A) on brain tissue in neonatal rats with hypoxic ischemic brain damage(HIBD). Methods: Totally 60 seven-day-old Wistar rats were divided into 6 groups (10 for each) randomly as below: normal control group, HIBD model group, fake surgery group and treatment groups I, II, and III (respectively injected into the belly cavity with different dosages of ACT A). The treatment groups were given ACT A instantly after hypoxic-ischemia(HI), and other groups were given the same volume of physiological saline. The specimens were collected in each time point(0,2,6,24,48 hours) after HI, then we observed the appearance of brain tissue disparity in the left and right brain weight , pathology and ultrastructure changes of brain tissue, and brain cell apoptosis by flow cytometry. Results: In each treatment group, the degrees of ecchymosis and dropsy of brain tissues alleviated obviously than those in model group on different time points after HI. The brain weight and the difference between left and right brain weight decreased obviously than those in the model group (1.21±0.07 vs 1.29±0.11, P0.05; 0.059±0.036 vs 0.092±0.063, P0.01). Under light microscope and electron microscope, plerosis of brain tissue in pathologic structure and ultrastructure was found in different degrees in treatment groups. The mean value of apoptosis in model group was obviously higher than that in treatment groups (7.46±0.12 vs 4.87±0.13, P0.05). Conclusion: The exogenous ACT A can protect the brain tissue by reducing the cerebral edema and depressing apoptosis in neonatal rat with HIBD.