| Objective: To investigate the effects of Qingtong Huayu Tang on the expression of nuclear transcription factor E2-related factor 2(Nrf2)and heme oxygenase 1(HO-1)in rats with cerebral ischemia-reperfusion injury,and to investigate the possible mechanism of action of Qingtong Huayu Tang in preventing cerebral ischemia-reperfusion injury in rats.Methods:(1)The hyperlipidaemic model was prepared by randomly dividing240 healthy male SD rats into 2 groups: blank(Blank)group(n=48),fed with normal chow for 4 weeks,and hyperlipidaemic group(n=192),fed with equal amount of hyperlipidaemic chow for 4 weeks.(2)The rats in the hyperlipidaemic group were randomly subdivided into 4 groups:sham-operated(Sham)group,model(I/R)group,Qing Tong Hua Yu Tang(QTHY)group and Tong Xin Luo(TXL)group,with 48 rats in each group.rats in the QTHY group were gavaged with Qing Tong Hua Yu Tang,rats in the TXL group were gavaged with Tong Xin Luo solution,and rats in the Sham and I/R groups were gavaged with an equal volume of distilled water.(3)A modified Longa wire bolus method was used to prepare the rat cerebral ischemia-reperfusion injury(I/R)model.The rats in each group were divided into 4 subgroups,i.e.3h,24 h,3d and 7d,with 12 rats in each group according to the time point of postoperative sampling.(4)The Zea Longa scale was used to assess the degree of neurological deficits in the rats;the enzyme-labeled colorimetric method was used to detect lipid levels;triphenyltetrazolium chloride(TTC)staining was used to measure the volume of cerebral infarction;DCFH-DA staining was used to analyze the content of reactive oxygen species(ROS);Western Blot,immunohistochemistry and q PCR were used to detect the expression levels of Nrf2,HO 1 expression levels were measured by Western Blot,immunohistochemistry and q PCR.Results:(1)(ⅰ)Rats in the Blank and Sham groups had no significant neurological deficits and scored zero,while rats in the I/R,QTHY and TXL groups all showed significant neurological deficits;(ii)Compared with the I/R group,rats in the QTHY and TXL groups showed improvement in neurological deficits(P<0.05),while the difference between the QTHY and TXL groups was not statistically significant(P>0.05).(2)Body mass and lipid levels at 7 d of cerebral ischemia-reperfusion:(i)Compared with the Blank group,body mass increased in all groups,and serum levels of TC,TG,and LDL-C increased and HDL-C decreased in all groups,with statistically significant differences(P < 0.05);(ii)Compared with Sham group,body mass was reduced in I/R group,QTHY group and TXL group,and the difference was statistically significant(P < 0.05),and there was no significant difference in serum lipid level(P > 0.05);(iii)Compared with the I/R group,the QTHY and TXL groups both had reduced body mass,reduced serum levels of TC,TG and LDL-C,and increased HDL-C levels,with statistically significant differences(P < 0.05),while there were no significant differences in body mass and lipid levels between the QTHY and TXL groups(P > 0.05).(3)Comparison of infarct volume,ROS content,Nrf2 and HO-1 at the same time points: 1)Infarct volume:(i)No white infarct foci were observed in the Blank and Sham groups,and significant white infarct foci were observed in the I/R,QTHY,and TXL groups in terms of brain infarct volume;(ii)compared with the I/R group,the infarct volume in the QTHY and TXL groups decreased(P<0.05),while there was no significant difference in lipid levels between the QTHY and TXL groups(P>0.05).2)ROS content:(i)compared with the Sham group,the ROS content in the I/R,QTHY and TXL groups was significantly higher(P<0.05);(ii)compared with the I/R group,the ROS content in the QTHY and TXL groups was reduced(P<0.05);(iii)compared with the TXL group,the ROS content in the QTHY group was more significant(P<0.05).3)Western Blot,immunohistochemistry and q PCR assays for the expression levels of Nrf2 and HO-1: at the same time points,(i)compared with the Sham group,the expression levels of Nrf2 and HO-1 were significantly lower in the I/R group,QTHY group and TXL group(P<0.05);(ii)compared with the I/R group,the expression levels of Nrf2 and HO-1expression levels were significantly higher in the QTHY and TXL groups compared with the I/R group(P<0.05);(iii)compared with the TXL group,the expression levels of Nrf2 and HO-1 were more significantly higher in the QTHY group(P<0.05).Conclusions: Qingtong Huayu Tang can improve the neurological function of cerebral ischemic injury in rats,and its mechanism of action may be related to increasing the expression of Nrf2 and HO-1 in ischemic brain tissues,reducing the accumulation of ROS and mitigating the oxidative stress injury of cerebral ischemia-reperfusion. |
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