目的:本研究旨在探讨广藿香醇(PA)对自发性高血压大鼠(SHR)肾病的保护作用,并揭示其可能的作用机制。
方法:简而言之,成年自发性高血压大鼠(SHR)或Wistar-Kyoto(WKY)大鼠(一半雄性和一半雌性)用PA(80、40和20mg/kg)灌胃或不灌胃8周。体重,血压(BP),肾重量,检测肾功能和肾脏形态。Further,免疫印迹和免疫组织化学分析用于研究潜在的机制。
结果:与WKY组相比,肾素的血浆水平,血管紧张素II(Ang-II),转化生长因子β1(TGF-β1),纤溶酶原激活物抑制剂-1(PAI-1),肌酐(Cr),血尿素氮(BUN),肾指数,ERK1/2和α-SMA的mRNA水平在SHR中显著升高。组织学结果显示SHR发生肾小管损伤和肾小管间质纤维化。给药后,卡托普利组SBP在给药后每周下降,尤其是在第3、5、6、7和8周(P<0.05或P<0.01)。在橄榄油组中没有评估到显著的效果。等离子体Cr降低,Renin,Ang-II,TGF-β1、PAI-1、SCFAs和肾素,肾组织中TGF-β1、PAI-1与卡托普利有显著性差异(P<0.05或P<0.01)。血浆BUN,Ang-II,橄榄油组肾组织中TGF-β1和PAI-1明显下降(P<0.05或P<0.01)。PA(80、40和20mg/kg)降低了肾素的BP和血浆水平,Ang-II,TGF-β1和PAI-1。用PA(40、20mg/kg)处理降低了Cr的水平,BUN和抑制肾脏中包括TGF-β1在内的促纤维化细胞因子的激活。橄榄油组和卡托普利组无改善性变化(P>0.05),而PA治疗减轻了肾小管损伤,并产生了肾小球系膜胶原纤维面积的显着减少。基底膜,肾间质明显(P<0.05或P<0.01)。用PA处理SHR抑制MFB激活和下调α-SMA的mRNA。用PA处理通过降低ColI抑制了细胞外基质(ECM)的过度产生,III和FN,下调组织抑制因子TIMP-1的mRNA,上调MMP-9的mRNA。卡托普利组ColⅢ和MMP-9mRNA表达降低(P<0.05)。此外,卡托普利组ERK1/2和pERK1/2的表达也显着降低(P<0.05或P<0.01)。用PA(20mg/kg)治疗下调Raf-1,ERK1/2和pERK1/2的蛋白表达和Ras的mRNA表达,Raf-1和ERK1/2。
结论:总体而言,PA恢复正常血压,减轻肾功能障碍和肾纤维化,可能通过抑制AngII和TGF-β1介导的Ras/Raf-1/ERK1/2信号通路。
OBJECTIVE: The present study was designed to obverse the protection of patchouli alcohol (PA) ameliorates hypertensive nephropathy in spontaneously hypertensive rats (SHR) and reveals potential mechanism.
METHODS: Briefly, the adult spontaneously hypertensive rats (SHR) or Wistar-Kyoto (WKY) rats (half male and half female) were intragastric gavaged or not with PA (80, 40 and 20 mg/kg) for 8 weeks. Body weight, blood pressure (BP), renal weight, renal function and renal morphology were measured. Further, western blotting and immunohistochemical analysis were used to study the underlying mechanism.
RESULTS: Compared with the WKY group, plasmatic levels of renin, angiotensin II (Ang-II), transforming growth factor beta 1(TGF-β1), plasminogen activator inhibitor-1(PAI-1), creatinine (Cr), blood urea nitrogen (BUN), renal index, mRNA levels of ERK1/2 and α-SMA were significantly increased in SHR. Histology results showed that renal tubular injury and tubulointerstitial fibrosis occurred in SHR. After administration, SBP of captopril group decreased at each week after administration, especially at 3, 5, 6 7 and 8 weeks (P < 0.05 or P < 0.01). There is no significant effect was assessed in the olive oil group. Decreased plasma Cr, Renin, Ang-II, TGF-β1, PAI-1, SCFAs and Renin, TGF-β1, PAI-1 in renal tissues were observed significantly in captopril (P <0.05 or P < 0.01). Plasma BUN, Ang-II, TGF-β1 and PAI-1 in renal tissues decreased in the olive oil group significantly (P <0.05 or P < 0.01). PA (80, 40 and 20 mg/kg) lowered BP and plasmatic levels of Renin, Ang-II, TGF-β1 and PAI-1. Treatment with PA (40, 20 mg/kg) decreased levels of Cr, BUN and suppressed of activation of pro-fibrosis cytokines including TGF-β1 in kidney. There is no ameliorative change in the olive oil group and the captopril group (P > 0.05) while PA treatment alleviated renal tubular injury and produced dramatic collagen fibre area reductions in mesangial membrane, basement membrane, and renal interstitium obviously (P < 0.05 or P < 0.01). Treatment of SHR with PA-inhibited MFB activation and downregulated mRNA of α-SMA. Treatment with PA suppressed excessive production of the extracellular matrix (ECM) via decreasing Col I, III and FN, downregulating mRNA of tissue inhibitor of TIMP-1 along with upregulating mRNA of MMP-9. The expression of Col III and MMP-9 mRNA-reduced in the captopril group (P < 0.05). In addition, the expression of ERK1/2 and pERK1/2 also reduced in the captopril group significantly (P < 0.05 or P < 0.01). Treatment with PA (20 mg/kg) downregulated proteins expression of Raf-1, ERK1/2 and pERK1/2 and mRNA expression of Ras, Raf-1 and ERK1/2.
CONCLUSIONS: Overall, PA restored normal BP, alleviated renal dysfunction and renal fibrosis, possibly by suppressing Ang II and TGF-β1-mediated Ras/Raf-1/ERK1/2 signalling pathway.