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目的 了解NiCl2 在体内对大鼠细胞的DNA产生何种损伤以及与聚腺苷二磷酸核糖聚合酶(PARP)活性的关系。方法 以 10 ,2 0 ,30mg·kg- 1NiCl2 ip给大鼠进行染毒 ,2 4h后处死动物 ,分离外周血淋巴细胞和肺细胞 ,应用单细胞凝胶电泳 (彗星试验 ) ,检测DNA单链、双链断裂和DNA 蛋白质交联 ,同时用 [3H]NAD渗透法检测PARP活性的变化。结果 外周血淋巴细胞和肺细胞均没有出现明显的DNA单链和双链断裂。所有剂量组的外周血淋巴细胞都出现了不同程度的DNA 蛋白质交联 ,交联率为 14 %～ 36 %,但没有剂量反应关系。 2 0mg·kg- 1NiCl2 也能诱导肺细胞DNA 蛋白质交联 ,交联率达 30 %。所有剂量组的NiCl2 均能明显抑制大鼠外周血淋巴细胞PARP酶的活性 ,酶活性下降至对照组的 38%～ 5 7%,但没有表现出剂量反应关系。大鼠肺细胞中该酶活性不受NiCl2 染毒的影响。结论 NiCl2 在体内环境下能诱导大鼠外周血淋巴细胞和肺细胞的DNA损伤 ,主要是引起DNA 蛋白质交联 ,而不直接造成DNA链的断裂 ;NiCl2 还能明显抑制外周血淋巴细胞的PARP酶活性 ,进而可能影响DNA修复。
Objective To investigate the DNA damage induced by NiCl2 in rat cells and its relationship with the activity of poly (ADP-ribose) polymerase (PARP). Methods The rats were exposed to 10, 20, 30 mg · kg-1 NiCl2 ip. After 24 h, the animals were sacrificed and peripheral blood lymphocytes and lung cells were isolated. Single-cell gel electrophoresis (comet assay) , Double-strand breaks and DNA proteins were cross-linked, and the change of PARP activity was detected by [3H] NAD infiltration method. Results No obvious DNA single-stranded and double-stranded breaks were found in peripheral blood lymphocytes and lung cells. All doses of peripheral blood lymphocytes appeared different degrees of DNA protein cross-linking, cross-linking rate of 14% to 36%, but no dose-response relationship. 20mg · kg-1NiCl2 can also induce lung cell DNA protein crosslinking, the crosslinking rate of 30%. All doses of NiCl2 can significantly inhibit the activity of PARP in rat peripheral blood lymphocytes, and the enzyme activity decreased to 38% ~ 57% of the control group, but no dose-response relationship was found. The enzyme activity in rat lung cells was not affected by NiCl2 exposure. Conclusion NiCl2 can induce DNA damage in peripheral blood lymphocytes and lung cells in vivo and mainly induce DNA protein cross-linking without directly causing DNA strand breaks. NiCl2 can also significantly inhibit PARP enzyme in peripheral blood lymphocytes Activity, which in turn can affect DNA repair.