枸杞多糖通过Nrf2/HO-1信号对百草枯致肺损伤的保护作用

Protective effects of lycium barbarum polysaccharides on paraquat induced lung injury via Nrf2/HO-1 signaling

目的探讨枸杞多糖(LBP)对百草枯(PQ)中毒肺损伤保护作用和分子机制。方法将雄性SD大鼠24只(8~10周龄,180~200 g体重)采用随机数字表法随机分为3组,分别为百草枯组(n=8):腹腔注射百草枯(20 mg/kg);PQ+LBP组(n=8):腹腔注射百草枯(20 mg/kg)后灌胃给予枸杞多糖(400 mg/kg);对照组(n=8):腹腔注射等量等渗盐水。各组大鼠于干预后3 d麻醉处死并留取肺组织标本,制作肺组织切片。通过HE染色观察分析组织损伤和炎症发生情况;通过检测大鼠肺湿/干重比(W/D)和羟脯氨酸含量进一步评估渗出及胶原沉积情况;通过试剂盒方法检测肺组织丙二醛(MDA)、髓过氧化物酶(MPO)和超氧化物歧化酶(SOD)水平;采用酶联免疫吸附实验(ELISA)检测肺组织白细胞介素-1β(IL-1β)和肿瘤坏死因子-α(TNF-α)的水平;Western blot检测核转录因子NF-E2相关因子2(Nrf2)和血红素加氧酶-1(HO-1)相关信号分子的表达情况。结果枸杞多糖处理后,百草枯造成的大鼠肺损伤得到减轻,PQ+LBP组大鼠肺组织的湿/干重比和羟脯氨酸含量较百草枯组显著降低(P<0.05)。PQ+LBP组大鼠肺组织MPO活性[(6.54±0.65)U/g]和MDA含量[(7.71±0.42)nmol/mg]较百草枯组[(16.49±0.59)U/g、(14.34±0.55)nmol/mg]下调(P<0.05),而SOD水平[(25.27±0.58)U/mg]较百草枯组[(12.25±0.62)U/mg]显著增加(P<0.05)。PQ+LBP组大鼠肺组织中炎症因子IL-1β[(115.93±3.17)pg/mg]和TNF-α[(66.34±4.27)pg/mg]的表达水平较百草枯组[(225.58±4.83)pg/mg、(167.00±5.80)pg/mg]下调(P<0.05)。PQ+LBP组大鼠肺组织中炎症因子IL-1β[(115.93±3.17)pg/mg]和TNF-α[(66.34±4.27)pg/mg]的表达水平较百草枯组[(225.58±4.83)pg/mg、(167.00±5.80)pg/mg]下调(P<0.05)。PQ+LBP组大鼠肺组织Nrf2和HO-1蛋白表达水平较百草枯组显著上调(P<0.05)。结论枸杞多糖能够通过抗氧化、抗炎等作用减轻百草枯造成的肺损伤,相关保护作用与Nrf2/HO-1信号途径关系密切。

Objective To investigate the protective effects and molecular mechanisms of lycium barbarum polysaccharides(LBP)on paraquat(PQ)induced lung injury.Methods Male SD rats(8-10 weeks old,180-200 g)were randomly divided into three groups:PQ group(n=8):intraperitoneal injection of PQ(20 mg/kg);PQ+LBP group(n=8):intraperitoneal injection of PQ(20 mg/kg),intragastric administration of LBP(400 mg/kg);control group(n=8):intraperitoneal injection of the same amount of saline.The rats were killed 3 days after the intervention,and the lung tissue samples were taken for further use.HE staining was used to analyze the occurrence of tissue injury and inflammation.The wet to dry weight ratio(W/D)and hydroxyproline content were detected to further evaluate the exudation and collagen deposition.The levels of malondialdehyde(MDA),myeloperoxidase(MPO)and su-peroxide dismutase(SOD)in lung tissue were detected by kit.The levels of interleukin-1β(IL-1β)and tumor necrosis factor-α(TNF-α)in lung tissue were detected by enzyme-linked immunosorbent assay(ELISA).The expression of nuclear factor erythroid 2-related factor 2(Nrf2)and heme oxygenase-1(HO-1)was detected by Western blotting assays.Results After treatment with LBP,the lung injury induced by PQ was alleviated.The W/D ratio and hydroxyproline content of lung tissues in PQ+LBP group were significantly lower than those in PQ group(P<0.05).The MPO activity[(6.54±0.65)U/g]and MDA content[(7.71±0.42)nmol/mg]of rat lung tissues in PQ+LBP group were lower than those in PQ group[(16.49±0.59)U/g,(14.34±0.55)nmol/mg](P<0.05),while SOD level[(25.27±0.58)U/mg]was significantly higher than that in PQ group[(12.25±0.62)U/mg](P<0.05).The levels of IL-1β[(115.93±3.17)pg/mg]and TNF-α[(66.34±4.27)pg/mg]in rat lung tissues of PQ+LBP group were lower than those of PQ group[(225.58±4.83)pg/mg,(167.00±5.80)pg/mg](P<0.05).At the same time,Nrf2/HO-1 signaling was up-regulated in PQ+LBP group(P<0.05).Conclusion LBP could alleviate the lung injury induced by PQ through anti-oxidation and anti-inflammatory effects via Nrf2/HO-1 signaling pathway.