Gurbuz N, Ozkul A, Burgaz S
Laboratory of Animal Breeding and Experimental Research Center, Faculty of Medicine, Gazi University, Ankara, Turkey.
J BUON. 2009 Oct-Dec;14(4):647-52.
To investigate the effects of vitamin C and N-acetylcysteine (NAC) against cyclophosphamide (CP) -induced genotoxic damage in exfoliated bladder cells of mice by micronucleus (MN) assay.
For each experimental step, 6-8 Swiss albino balb/c male mice were used. CP was used as positive control. Vitamin C (10, 30 and 60 mg/kg) and CP (51.6 mg/kg) were administered intraperitoneally to the experimental animals. Vitamin C was administered twice, one dose 24 h prior to the CP administration and the second dose simultaneously with the CP. NAC (200, 400 and 800 mg/kg) was administered by gavage for 7 consecutive days before the injection of CP. Distilled water and normal saline as negative controls I and II were used, respectively. Ten days after CP treatment, the mice were sacrificed and bladders were isolated and cut, and exfoliated cells were scraped from the bladder walls. Air-dried smears were stained by Feulgen reaction. MN frequencies were scored in 1000 epithelial cells per animal and defined as MN per thousand (per thousand).
Three doses of vitamin C (10, 30 and 60 mg/ kg) showed a significant inhibitory effect on MN frequencies in mouse bladder cells when compared with those of positive control group (p <0.05). Dose-dependent inhibitory effect of vitamin C was observed only between the doses of 10 and 60 mg/kg (p <0.05). Histopathological changes that depended on CP- induced inflammatory infiltration and haemorrhage in mucosa propria were not observed in all 3 vitamin C doses. Three doses of NAC (200, 400 and 800 mg/kg) inhibited the CP-induced genotoxicity (p <0.05), however, the antigenotoxic effect of NAC was not dose-dependent. Histopathological changes that depended on CP-induced inflammatory infiltration and haemorrhage in mucosa propria were not observed in 200 and 400 mg/kg NAC dosage. The extent of desquamation in bladder was similar in all 3 doses of NAC when compared with the positive control group.
Our study indicated that vitamin C and NAC reduced the CP-induced MN frequencies in target (bladder) cells of mice by 41-71% in all cases. The modifying effects of vitamin C and NAC against CP-induced genotoxic damage may be due to their antioxidant, nucleophilic properties and to the ability to act as precursors of glutathione.
通过微核（MN）试验研究维生素C和N-乙酰半胱氨酸（NAC）对环磷酰胺（CP）诱导的小鼠膀胱脱落细胞遗传毒性损伤的影响。
每个实验步骤使用6-8只瑞士白化病balb/c雄性小鼠。CP用作阳性对照。将维生素C（10、30和60mg/kg）和CP（51.6mg/kg）腹腔注射给实验动物。维生素C给药两次，一次剂量在CP给药前24小时，第二次剂量与CP同时给药。NAC（200、400和800mg/kg）在注射CP前连续7天通过灌胃给药。分别使用蒸馏水和生理盐水作为阴性对照I和II。CP处理10天后，处死小鼠，分离并切开膀胱，从膀胱壁刮取脱落细胞。空气干燥涂片用Feulgen反应染色。对每只动物的1000个上皮细胞进行微核频率评分，并定义为每千个细胞中的微核数（每千个）。
与阳性对照组相比，三种剂量的维生素C（10、30和60mg/kg）对小鼠膀胱细胞中的微核频率均有显著抑制作用（p<0.05）。仅在10至60mg/kg剂量之间观察到维生素C的剂量依赖性抑制作用（p<0.05）。在所有三种维生素C剂量下均未观察到依赖于CP诱导的黏膜固有层炎症浸润和出血的组织病理学变化。三种剂量的NAC（200、400和800mg/kg）均抑制了CP诱导的遗传毒性（p<0.05），然而，NAC的抗遗传毒性作用不是剂量依赖性的。在200和400mg/kg NAC剂量下未观察到依赖于CP诱导的黏膜固有层炎症浸润和出血的组织病理学变化。与阳性对照组相比，所有三种剂量的NAC膀胱脱屑程度相似。
我们的研究表明，在所有情况下，维生素C和NAC均可使小鼠靶细胞（膀胱）中CP诱导的微核频率降低41%-71%。维生素C和NAC对CP诱导的遗传毒性损伤的修饰作用可能归因于它们的抗氧化、亲核特性以及作为谷胱甘肽前体的能力。
