Abstract:

To explore the protective effects of exogenous activin A (ACT A) on brain cell apoptosis of neonatal rats with hyperbilirubinemia.  Methods96 sevendayold Wistar rats were randomly divided into the normal control group(C0), the hyperbilirubinemia control group (C1) and the ACT A treatment Ⅰ and Ⅱ groups (T1, T2). The hyperbilirubinemia control group and both ACT A treatment groups were intraperitoneally(I.P.) injected with bilirubin. The ACT A treatment Ⅰ and Ⅱ groups were orally given a high or low dose of ACT A respectively right after I.P. Bilirubin contents (TB) in the serum and brain tissues were measured by Diazo reaction, brain tissue ultrastructure was observed under an electron microscope, and brain tissue apoptosis analysis was done by flow cytometry.  ResultsThe neurobehavioral abnornalities of the C1 group was significantly more severe than those of the T1 and T2 groups. The mean TB in both serum and brain tissues of the C1, T1, and T2 groups was higher than that of the C0 group（P all＜0.01）. The mean TB of T1 and T2 in both serum and brain tissues was lower than that of the C1 group（P all ＜0.05）. The mean TB of the T1 group in both serum and brain tissues was lower than that of the T2 group（P all ＜0.01）. Under an electron microscope, the neurons in the C1 group were significantly damaged. Plerosis of ultramicrostructure of different degrees was found in the T1 and T2 groups compared with the C1 group. The results of flow cytometry showed that the mean value of brain cell apoptosis at 12?h in the C1, T1, and T2 groups was higher than that of the C0 group (P all ＜0.001）. The mean value of brain cell apoptosis at 12?h in the T1 and T2 groups was lower than that of the C1 group（P all ＜0.05）. The mean value of the brain cell apoptosis at 12?h in the T1 group was lower than that of the T2 group (P＜0.001）.  ConclusionExogenous ACT A can significantly reduce the accumulation of bilirubin, depress  brain cell apoptosis, and protect the brain tissue of neonatal rats with hyperbilirubinemia.

Key words: Exogenous activin A; Hyperbilirubinemia; Flow cytometry; Apoptosis;Rats, Wistar