目的　论证线粒体DNA(mitochondrial,mtDNA)“常见缺失”与DNA氧化损伤的关系。方法　采用连接介导PCR(ligationmediatedPCR ,LMPCR) ,在大鼠肝细胞株 (BRL 3A)暴露于 5 0mmol/L过氧化氢 (H2 O2 )形成氧化损伤后 ,分析该缺失的断裂区段 (80 71～ 8190 ,约 12 0bp)内 ,各核苷酸氧化损伤的频率及热点。结果　在 80 71～ 8190区段 ,存在 8181G、8182G两个明显的氧化损伤热点 ,810 8C及80 96～ 810 1(6bp)的损伤亦明显 ;而“常见缺失”的断裂位点 (8118T)并未被明显氧化损伤。其中 ,8181G/ 8182G位于一个DNA重复结构内 ,80 96～ 810 1(6bp)则位于一个DNA回文结构内。结论　线粒体DNA“常见缺失”的断裂位点不一定是氧化损伤的热点 ,但在断裂区段内存在 2个氧化损伤热点 Objective To investigate the relationship between “common deletion” of mitochondrial DNA (mtDNA) and DNA oxidative damage. Methods Ligation-mediated PCR (LMPCR) was used to analyze the deletion of the fragmented segment in rat hepatocyte cell line BRL 3A exposed to 50 mmol / L hydrogen peroxide (H 2 O 2) ~ 8190, about 12 0bp), the frequency and hot spots of each nucleotide oxidative damage. Results There were two obvious oxidative damage hot spots 8181G and 8182G in section 8071 ~ 8190, with significant damage at 8108C and 8096 ~ 810 1 (6bp). The site of “common deletion” (8118T) Not significantly oxidative damage. Among them, 8181G / 8182G is located in a DNA repeat structure, 8096 ~ 810 1 (6bp) is located in a DNA palindrome structure. Conclusion The “common deletion” sites of mitochondrial DNA may not be the hot spots of oxidative damage, but there are two hot spots of oxidative damage in the fracture zone