石墨烯对大鼠亚急性毒性试验的相关氧化指标观察

Observation on related oxidation indexes in subacute toxicity test of graphene in rats

目的从氧化应激角度探讨石墨烯(GP)对大鼠肺损伤的作用机制。方法选择96只健康Wistar大鼠,按体重随机分为阴性对照组、GP低剂量组(2.5 mg/kg)、GP中剂量组(5 mg/kg)和GP高剂量组(7.5 mg/kg),每组24只。各GP剂量组大鼠均采用一次性经口气管灌注不同浓度GP悬浊液。于术后24 h、3天和7天分别处死4组大鼠每组8只,腹主动脉取血,观察各组大鼠亚急性毒性期内血清中超氧化物歧化酶(SOD)活力、丙二醛(MDA)含量、一氧化氮(NO)及诱导型一氧化氮合酶(iNOS)的含量。结果GP染毒亚急性期各时间点4项氧化损伤指标的组间比较结果显示,组间比较差异均有统计学意义(均P<0.01)。仅术后第7天的GP中剂量组和低剂量组SOD水平与对照组比较差异有统计学意义(P<0.05),其他时间点各剂量组SOD水平与对照组比较,差异均有统计学意义(均P<0.01),且具有剂量-效应关系。除术后第3天GP低剂量组MDA含量与对照组比较,差异无统计学意义(P>0.05),在各时间点中GP各剂量组与对照组比较,差异均有统计学意义(均P<0.05)。在3个不同时间点各剂量组的i NOS和NO含量与对照组比较,差异均有统计学意义(均P<0.05),且iNOS和NO的含量变化始终保持同步升高的趋势。结论在GP经气管滴注后的亚急性期内,各时间段大鼠血清中氧化应激指标SOD活力水平下降,MDA含量升高,NO水平和iNOS活力均同步提高,提示GP肺暴露后存在氧化损伤作用,并可能存在时间剂量反应关系。

Objective To explore the mechanism of graphene on lung injury in rats from the perspective of oxidative stress.Methods Totally 96 healthy Wistar rats were randomly divided into negative control group,graphene low-dose group(2.5 mg/kg),graphene medium-dose group(5 mg/kg)and graphene high-dose group(7.5 mg/kg)according to body weight,24 in each group.Rats in each graphene dose group were given a single oral tracheal infusion of different concentrations of graphene suspension.Eight rats in each of the four groups were sacrificed at 24 hours,3 rd and 7 th days after operation.Blood samples were collected from the abdominal aorta to observe the activity of superoxide dismutase(SOD)in the serum of each group during the subacute toxicity,malondialdehyde(MDA)content,nitric oxide(NO)and inducible nitric oxide synthase(iNOS)contents.Results There were statistically significant differences in four oxidative damage indicators at each time point in the subacute phase of graphene exposure among the groups(P<0.01).Only on the 7 th day after operation,the SOD levels of the graphene middle-dose group and the low-dose group were significantly different from those of the control group(P<0.05).The differences in the SOD levels at other time points between each dose group and the control group were statistically significant(all P<0.01),and there was a dose-effect relationship.There was no statistically significant difference in the MDA content between the graphene low-dose group and the control group on the 3 rd day after operation(P>0.05),while the differences at each time point were statistically significant between the graphene dose groups and the control group(all P<0.05).At three different time points,the differences in the iNOS and NO contents were statistically significant between each dose group and the control group(all P<0.05),and the changes in iNOS and NO contents always maintained a synchronous increase trend.Conclusion During the subacute period of graphene endotracheal intubation,the oxidative stress index SOD activity level in the serum of rats decreases at various time periods,MDA content increases,and both NO level and iNOS activity increase simultaneously,suggesting that there is oxidative damage after graphene lung exposure,and there may be a time-dose response relationship.