Tetramethylpyrazine protects mice against thioacetamide-induced acute hepatotoxicity

In this study, the intraperitoneal administration of 1 mg/kg thioacetamide (TAA) produced hepatotoxicity in mice. The increase in serum SGOT and SGPT produced at 24 h by this regimen was decreased in a dose-dependent manner by coadministration of tetramethylpyrazine (TMP; 10, 25 and 50 mg/kg). A rise in serum interleukin-2 was similarly prevented. Increased concentrations of malondialdehyde (MDA) generated in vitro in liver homogenates prepared from TAA-treated mice were decreased by TMP treatments. The increase in MDA produced by TAA was also prevented by in vitro addition of TMP to liver homogenates. These results suggest that part of the hepatocellular injury induced by TAA is mediated by oxidative stress caused by the action of cytokines through lipid peroxidation. TMP appears to act by preventing lipid peroxidation.     

Tetramethylpyrazine inhibits CoCl2‐induced neurotoxicity through enhancement of Nrf2/GCLc/GSH and suppression of HIF1α/NOX2/ROS pathways

Hypoxia‐mediated neurotoxicity contributes to various neurodegenerative disorders, including Alzheimer's disease and multiple sclerosis. Tetramethylpyrazine (TMP), a major bioactive component purified from Ligusticum wallichii Franchat, exhibited potent neuroprotective effect. However, the mechanism of TMP‐exerted neuroprotective effect against hypoxia was not clear. In the study, we investigated the mechanism of the neuroprotective effect of TMP against hypoxia induced by CoCl₂ in vitro and in vivo. The results showed that TMP could protect against CoCl₂‐induced neurotoxicity in PC12 cells and in rats, as evidenced by enhancement of cell viability in PC12 cells and improvement of learning and memory ability in rats treated with CoCl₂. TMP could inhibit mitochondrial dysfunction, mitochondrial apoptotic molecular events, and thus apoptosis induced by CoCl₂. TMP inhibited CoCl₂‐increased reactive oxygen species (ROS) level, which may contribute to hypoxia‐related neurotoxicity induced by CoCl₂. The antioxidant and neuroprotective activities of TMP involved two pathways: one was the enhancement of nuclear factor erythroid 2‐related factor 2 (Nrf2)/catalytic subunit of γ‐glutamylcysteine ligase‐mediated regulation of GSH and the other was the inhibition of hypoxia‐inducible factor 1 α/NADPH oxidase 2 (NOX2)‐mediated ROS generation. These two pathways contributed to improvement of oxidative stress and thus the amelioration of apoptosis under hypoxic conditions. These results have appointed a new path toward the understanding of pathogenesis and TMP‐related therapy of hypoxia‐related neurodegenerative diseases.

     

Neuroprotective Effects of Tetramethylpyrazine against Dopaminergic Neuron Injury in a Rat Model of Parkinson's Disease Induced by MPTP

Parkinson''s disease (PD) is the second most prevalent progressive neurodegenerative disease. Although several hypotheses have been proposed to explain the pathogenesis of PD, apoptotic cell death and oxidative stress are the most prevalent mechanisms. Tetramethylpyrazine (TMP) is a biological component that has been extracted from Ligusticum wallichii Franchat (ChuanXiong), which exhibits anti-apoptotic and antioxidant roles. In the current study, we aimed to investigate the possible protective effect of TMP against dopaminergic neuron injury in a rat model of Parkinson''s disease induced by MPTP and to elucidate probable molecular mechanisms. The results showed that TMP could notably prevent MPTP-induced dopaminergic neurons damage, reflected by improvement of motor deficits, enhancement of TH expression and the content of dopamine and its metabolite, DOPAC. We observed MPTP-induced activation of mitochondrial apoptotic death pathway, evidenced by up-regulation of Bax, down-regulation of Bcl-2, release of cytochrome c and cleavage of caspase 3, which was significantly inhibited by TMP. Moreover, TMP could prevent MPTP-increased TBARS level and MPTP-decreased GSH level, indicating the antioxidant role of TMP in PD model. And the antioxidant role of TMP attributes to the prevention of MPTP-induced reduction of Nrf2 and GCLc expression. In conclusion, in MPTP-induced PD model, TMP prevents the down-regulation of Nrf2 and GCLc, maintaining redox balance and inhibiting apoptosis, leading to the attenuation of dopaminergic neuron damage. The effectiveness of TMP in treating PD potentially leads to interesting therapeutic perspectives.     

川芎嗪与秋水仙碱抗肝纤维化的实验研究

实验ＳＤ大鼠随机分为正常组、ＣＣｌ４组、川芎嗪组和秋水仙碱组。实验结果显示：与ＣＣｌ４组比较,川芎嗪组血清ＡＬＴ、丙二醛（ＭＤＡ）、Ⅲ型前胶原（ＰＣⅢ）、透明质酸（ＨＡ）及肝组织ＭＤＡ明显减低,肝组织超氧化物歧化酶（ＳＯＤ）活性显著提高,胶原纤维增生程度显著减轻,结蛋白（Ｄｅｓｍｉｎ）阳性细胞显著减少。两治疗组之间,血清ＰＣⅢ、ＨＡ及肝组织Ｄｅｓｍｉｎ阳性细胞数和胶原纤维增生程度无显著差异。表明川芎嗪有明显保护肝细胞、抗脂质过氧化和肝纤维化作用。秋火仙碱抗肝纤维化效应与之相似,但无抗脂质过氧化和保护肝细胞作用。     

川芎嗪联合缬沙坦治疗糖尿病肾病肾衰竭的临床疗效观察

目的:探讨川芎嗪联合缬沙坦治疗糖尿病肾病肾衰竭的临床疗效。方法:选择我院2011年1月至2013年1月收治的糖尿病肾病肾衰竭患者96例,并将其随机分为实验组和对照组,每组48例。两组患者均根据病情给予对症支持治疗,并严格控制血糖。在常规治疗基础上,实验组患者给予川芎嗪注射液240 mg,静脉滴注,1次/d,同时给予缬沙坦80 mg,口服,1次/d,21天为1个疗程;对照组患者给予缬沙坦80 mg,口服,1次/d,21天为1个疗程。1个疗程后观察两组患者的临床疗效、血液学指标、尿检指标等实验室检查。结果:治疗21天后,实验组的临床有效率达83.3%,显著高于对照组(60.4%),差异具有统计学意义(P0.05);两组空腹血糖、尿蛋白、尿素氮、血肌酐水平均较治疗前显著改善,且实验组以上指标及胆固醇水平的改善程度明显优于对照组,差异有统计学意义(P0.05)。治疗过程中,两组均无严重不良反应发生。结论:川芎嗪联合缬沙坦可以更有效地改善糖尿病肾病肾衰竭患者的临床疗效,有一定的临床应用价值。     

Involvement of intracellular and extracellular Ca2+ in tetramethylpyrazine-induced colonic anion secretion

In the present study we investigated the role of Ca(2+) in tetramethylpyrazine (TMP)-induced anion secretion in the human colonic epithelial cell line, Caco-2, using the short-circuit current (I(SC)) technique in conjunction with intracellular Ca(2+) measurements. The results showed that TMP-induced I(SC) response was significantly reduced by 58.8% and 38.3% after inhibiting Ca(2+) ATPase of endoplasmic reticulum (ER) with thapsigargin and mobilizing ER stored Ca(2+) release with ATP, respectively. Conversely, thapsigargin- and ATP-evoked I(SC) responses were also significantly reduced by pretreatment with TMP by 43.2% and 38.5%, respectively. Conversely, removal of extracellular Ca(2+), apical but not basolateral, or the presence of the Ca(2+) chelator (EGTA) significantly increased TMP-induced I(SC) by 47.1% and 37.8%, respectively. Similar to TMP, thapsigargin-induced current increase was also enhanced by chelating extracellular Ca(2+) or in Ca(2+) free solution; however, removal of extracellular Ca(2+) did not significantly affect 3-isobutyl-1-methylxanthine (IBMX)- and forskolin-induced transepithelial current. Measurement of the intracellular concentration of free Ca(2+) ([Ca(2+)](i)) with fura-2/AM showed that TMP could induce an increase in [Ca(2+)](i) but pretreatment with TMP significantly reduced thapsigargin-evoked, but not ATP-induced, [Ca(2+)](i) increase. These results suggest that the effect of TMP on colonic anion secretion is partly mediated by TMP-increased [Ca(2+)](i) by acting on a target similar to thapsigargin. The observed inhibitory effect of extracellular Ca(2+) on Ca(2+)-dependent anion secretion represents a novel mechanism by which Ca(2+)-dependent regulation of epithelial electrolyte transport may be fine-tuned by extracellular Ca(2+) in the apical domain.     

Inhibitory effects of potassium channel blockers on tetramethylpyrazine-induced relaxation of rat aortic strip in vitro

Tetramethylpyrazine (TMP) is one of the active principles contained in Ligusticum chuanxiong Hort. (Umbelliferae), a herb that has been widely used to treat vascular disorders in China. In the present study, role of potassium channel in the vasodilatation of TMP was investigated using the effect of potassium channel blocker on TMP induced relaxation in isolated aortic rings from Wistar rats. TMP produced a concentration-dependent relaxation in the aortic rings precontracted with vasopressin or phenylephrine. Similar effect of TMP on vasoconstrictions by phenylephrine and vasopressin, induced through two different receptors, indicating the direct vasodilatation of TMP. Specific inhibitors for potassium channel were used to characterize the role of potassium channel in this action of TMP. Only the inhibitors specific to small conductance calcium-activated potassium (SK(Ca)) channel or ATP-sensitive potassium (K(ATP)) channel inhibited the action of TMP. Also, the TMP-induced relaxation was reversed by the inhibitor of soluble guanylyl cyclase in a way similar to that of K(ATP) channel blockade. The obtained results indicated that vasodilatation induced by TMP is related to the opening of SK(Ca) and K(ATP) channels.     

Protection by tetramethylpyrazine in acute absolute ethanol-induced gastric lesions

Acute oral administration of absolute ethanol (1.0 ml/kg) to fasting rats produced extensive necrosis of the gastric mucosa within 1 h. Pretreatment 30 min before administration of ethanol with oral tetramethylpyrazine (TMP) prevented this necrosis. Gross examination of the gastric mucosa of rats that received TMP showed fewer gastric lesions than that of rats who did not receive TMP. TMP pretreatment in rats exhibited superoxide scavenging activity in absolute ethanol-induced lipid peroxidation in gastric mucosal homogenates. TMP added in vitro to gastric homogenates made from control rats also showed scavenging activity. We conclude that the gastric protective mechanism of TMP could be attributed, at least in part, to its ability to inhibit lipid peroxidation and hence indirectly protect the gastric mucosa from oxidative stress.