Autophagy Mediates The Degradation Of MBP In Cerebral White Matter Damage Model

Objectives:To investigate the effect of autophagy in cerebral white matter damage in neonatal hypoxia-ischemia.Method: Postnatal day(P) 3 Sprague-Dawley(SD) rats were randomized into Sham group(n=50) and hypoxia-ischemia(HI) group(n= 50), In HI group, SD rats were subjected to 6% oxygen for 40 min after left carotid artery ligation on;Cerebral white matter damage was evaluated by observing rats’ left eye open time, histopathological changes and ultrastructural findings. Immunohistochemical staining and Western blot was used to study the expression level of MBP, LC3 and Beclin1 The data were analyzed by using SPSS17.0 statistical software.Results:(1) In HI group, rats’ eyes open time were delayed(P<0.05); HI groups’ cerebral white matter rarefaction was showed with HE staining, lower myelin formation and increasing autophagosomes were observed by TEM;(2) The expression of MBP significantly reduced in 48 h after hypoxia-ischemia(P<0.05);(3) After HI12 h, autophagy can be found in neonatal white matter by Western blot, and the peak was on HI 48h(P<0.05);(4) Immunofluorescence double-staining showed that the expression of LC3 and MBP were partly overlap.Conclusions:(1) Autophagy can be induced in cerebral white matter after hypoxia-ischemia in a time-dependence pattern;(2) The higher autophagy and lower expression of MBP after HI may be related that autophagy may play an important role cerebral white matter damage.