松果菊苷对尿毒症大鼠肾损伤的影响及机制

Effects of echinacoside on renal injury in uremia rats and its mechanism

目的研究松果菊苷(ECH)对尿毒症(URE)大鼠肾损伤的影响及机制。方法采用5/6肾切除法建立URE大鼠模型。建模成功的大鼠分为尿毒症(URE)组、ECH低剂量[10 mg/(kg·d)]组、ECH中剂量组[20 mg/(kg·d)]、ECH高剂量组[40 mg/(kg·d)]和ECH高剂量+茴香霉素[p38丝裂原活化蛋白激酶(p38 MAPK)信号通路激活剂]组[ECH-H+Ani组,40 mg/(kg·d)ECH+2 mg/(kg·d)茴香霉素],另设假手术组,每组12只。各药物组灌胃相应的ECH,ECH-H+Ani组再尾静脉注射茴香霉素,每天1次,连续给药8周。检测大鼠血清中肿瘤细胞因子α(TNF-α)、白细胞介素1β(IL-1β)、IL-6、血尿素氮(BUN)、β2-微球蛋白(β2-MG)、血肌酐(Scr)、中性粒细胞明胶酶相关载脂蛋白(NGAL)、肾损伤分子1(KIM-1)、胱抑素C(Cys-C)水平,24 h尿蛋白(24 h UP)和肾组织中丙二醛(MDA)水平、超氧化物歧化酶(SOD)活性;观察肾组织病理学变化;检测大鼠肾组织中α-平滑肌肌动蛋白(α-SMA)、E-上皮钙黏素(E-cadherin)阳性表达率和p38 MAPK、核因子κB(NF-κB)p65的磷酸化水平。结果与URE组相比,ECH各剂量组大鼠肾小球肿胀及上皮细胞损伤坏死明显减轻,炎症细胞浸润明显减少;肾损伤评分和TNF-α、IL-1β、IL-6、BUN、Scr、β2-MG、24 h UP、NGAL、KIM-1、Cys-C、MDA水平及α-SMA阳性表达率、p38 MAPK和NF-κB p65的磷酸化水平均呈剂量依赖性降低而SOD活性和E-cadherin阳性表达率均呈剂量依赖性升高(P<0.05)。茴香霉素可显著逆转高剂量ECH对URE大鼠肾损伤及相关指标的改善作用(P<0.05)。结论ECH可能通过抑制p38 MAPK/NF-κB信号通路激活来抑制URE大鼠的炎症反应和氧化应激反应,增强肾功能,改善肾损伤。

OBJECTIVE To investigate the effects of echinacoside(ECH)on renal injury in uremia(URE)rats and its mechanism.METHODS URE model of the rat was established by 5/6 nephrectomy.Successfully modeled rats were grouped into uremia group(URE group),ECH low-dose[10 mg/(kg·d)]group,ECH medium-dose[20 mg/(kg·d)]group,ECH high-dose[40 mg/(kg·d)]group,ECH high-dose+anisomycin[p38 mitogen-activated protein kinase(p38 MAPK)pathway activator]group[ECH-H+Ani group,40 mg/(kg·d)ECH+2 mg/(kg·d)anisomycin],with a sham operation group,12 mice in each group.Each drug group was given corresponding ECH intragastrically,while ECH-H+Ani group was further injected with anisomycin via the tail vein,once a day,for 8 consecutive weeks.The serum levels of tumor necrosis factor-α(TNF-α),interleukin-1β(IL-1β),IL-6,blood urea nitrogen(BUN),β2-microglobulin(β2-MG),serum creatinine(Scr),neutrophil gelatinase-associated lipocalin(NGAL),kidney injury molecule-1(KIM-1),cystatin C(Cys-C)and 24 h urine protein(24 h UP)as well as the levels of malondialdehyde(MDA)and superoxide dismutase(SOD)activity in renal tissue were all detected;pathological changes of renal tissue were observed;the rate of positive expression ofα-smooth muscle protein(α-SMA)and E-cadherin,and the phosphorylation of p38 MAPK and nuclear factor-κB(NF-κB)p65 were determined in renal tissue of rats.RESULTS Compared with URE group,glomerular swelling,damage and necrosis of renal tubular epithelial cells and inflammatory cell infiltration were relieved significantly in ECH groups.The renal injury score,levels of TNF-α,IL-1β,IL-6,BUN,Scr,β2-MG,24 h UP,NGAL,KIM-1,Cys-C and MDA,the positive expression rate ofα-SMA in renal tissue,the phosphorylation of p38 MAPK and NF-κB p65 were decreased in dose-dependent manner,while SOD activity and the positive expression rate of E-cadherin were obviously increased in dose-dependent manner(P<0.05).Anisomycin significantly attenuated the improvement effect of high-dose ECH on renal injury in URE rats(P<0.05).CONCLUSIONS ECH may inhibit inflammation and oxidative stress,enhance renal function,and improve renal injury in uremic rats by inhibiting the activation of p38 MAPK/NF-κB signaling pathway.