文本框: HYPOXIA-ISCHEMIA CAUSES THE DAMAGE OF BRAIN MITOCHONDRIAL DNA IN NEWBORN PIGLETS Shi J, Yao Y, Li W, Chen Y, Xiong Y Second Hospital, West China University of Medical Sciences, China Objective: To investigate the 8003 base pair (bp) fragmentation of brain mitochondrial DNA in newborn piglets at different time after brain hypoxia-ischemia. Methods: 3-day-age wenjiang piglets (n=50) were randomly divided into four experiment groups and a control group. After the ligatation of the left common carotid atery, the experiment groups were put into a container full of 8% O2 and 92% N2 for 2 hours, and then exposed in normal atmosphere respectively for 0 hour, 24 hours, 48 hours and 72 hours before executed. While the control group was performed sham surgeries and exposed in normal atmosphere. The left gerbil hippocampral cortex of all the groups were obtained to amplify the fragments of 200bp and 8003 bp by PCR method. The 200 bp was used to represent intra-contrast. Results: The integral optical density (IOD) of 8003bp fragment reduced dramatically in 0 hour post-hypoxic-ischemic group when compared to that of control group (p<0.05). The IOD of 8003bp somewhat restored in 24 hours post-hypoxic-ischemic group. In 72 hrs post-hypoxic-ischemic group, the IOD mainly recovered to normal. Conclusion: The mitochondrial DNA of the newborn piglet brain was fragmented under the conditions of brain hypoxia-ischemia .It would not recovered to nomal untill 72 hours post-hypoxia-ischemia. 0774