1. The aim of the present study was to evaluate the effect of pyrrolidine dithiocarbamate (PDTC), an inhibitor of nuclear factor-kappa B (NF-kappa B), on septic shock induced by Escherichia coli lipopolysaccharide (LPS) in spontaneously hypertensive rats (SHR). 2. After injection of LPS in SHR, a marked decrease in blood pressure was observed at 3 h and vascular hyporeactivity to noradrenaline (NA) was observed after 1 h. A marked increase in plasma levels of tumour necrosis factor-alpha (TNF-alpha) and nitrite (an indicator of nitric oxide) was also observed in SHR. 3. The delayed hypotension and hyporeactivity to NA induced by LPS were significantly reserved by pretreatment of rats with PDTC (10 mg/kg). The increase in plasma levels of TNF-alpha and nitrite in LPS-treated groups was also significantly suppressed by PDTC pretreatment. In addition, the survival time of SHR treated with LPS was significantly prolonged by PDTC pretreatment. 4. The present ex vivo study demonstrates that the NA-induced contraction is attenuated and the L-arginine-induced relaxation is enhanced in aortic rings obtained from LPS-treated SHR. Both the reduction of the NA-induced contraction and the increase of L-arginine-induced relaxation were reversed by pretreatment with PDTC. However, the relaxation elicited by acetylcholine (ACh) was not affected in LPS-treated SHR when compared with sham-operated SHR. In addition, the ACh-induced relaxation in LPS-treated SHR was not affected by PDTC pretreatment. 5. In normotensive Wistar-Kyoto (WKY) rats, LPS had mild effects on blood pressure, vascular hyporeactivity and plasma levels of TNF-alpha and nitrite. At a higher dose, PDTC (10 mg/kg) also prolonged survival time and improved haemodynamics in LPS-treated WKY rats. In the ex vivo study, it was noted that the relaxation elicited by ACh was significantly (P < 0.05) attenuated in LPS-treated WKY rats. This attenuation of the ACh-induced relaxation by LPS in WKY rats was significantly reversed by pretreatment with 10 mg/kg PDTC. 6. In conclusion, PDTC prolongs survival time in rats with endotoxaemia and improves the septic shock syndromes both in vivo and ex vivo. Thus, we propose that PDTC may be of use in septic patients.
It is well documented that 17beta-estradiol (E(2)) exerts a cardiovascular protective effect. A possible role of E(2) in the regulation of endothelin-1 (ET-1) production has been reported. However, the complex mechanisms by which E(2) inhibits ET-1 expression are not completely understood. The aims of this study were to examine whether E(2) may alter angiotensin II (Ang II)-induced cell proliferation and ET-1 gene expression and to identify the putative underlying signaling pathways in rat aortic smooth muscle cells. Cultured rat aortic smooth muscle cells were preincubated with E(2), then stimulated with Ang II, and [(3)H]thymidine incorporation and ET-1 gene expression were examined. The effect of E(2) on Ang-II-induced extracellular signal-regulated kinase (ERK) phosphorylation was tested to elucidate the intracellular mechanism of E(2) in proliferation and ET-1 gene expression. Ang II increased DNA synthesis which was inhibited with E(2) (1- 100 nM). E(2), but not 17alpha-estradiol, inhibited the Ang-II-induced ET-1 gene expression as revealed by Northern blotting and promoter activity assay. This effect was prevented by coincubation with the estrogen receptor antagonist ICI 182,780 (1 microM). E(2) also inhibited Ang-II-increased intracellular reactive oxygen species (ROS) as measured by a redox-sensitive fluorescent dye, 2',7'-dichlorofluorescin diacetate, and ERK phosphorylation. Furthermore, E(2) and antioxidants, such as N-acetyl cysteine and diphenylene iodonium, decreased Ang-II-induced cell proliferation, ET-1 promoter activity, ET-1 mRNA, ERK phosphorylation, and activator protein-1-mediated reporter activity. In summary, our results suggest that E(2) inhibits Ang-II-induced cell proliferation and ET-1 gene expression, partially by interfering with the ERK pathway via attenuation of ROS generation. Thus, this study provides important new insight regarding the molecular pathways that may contribute to the proposed beneficial effects of estrogen on the cardiovascular system.
Tetramethylpyrazine (TMP) is the major component extracted from the Chinese herb, Chuanxiong, which is widely used in China for the treatment of cardiovascular problems. The aims of this study were to examine whether TMP may alter angiotenisn II (Ang II)-induced proliferation and to identify the putative underlying signaling pathways in rat aortic smooth muscle cells. Cultured rat aortic smooth muscle cells were preincubated with TMP and then stimulated with Ang II, [3H]-thymidine incorporation and the ET-1 expression was examined. Ang II increased DNA synthesis which was inhibited by TMP (1-100 microM). TMP inhibited the Ang II-induced ET-1 mRNA levels and ET-1 secretion. TMP also inhibited Ang II-increased NAD(P)H oxidase activity, intracellular reactive oxygen species (ROS) levels, and the ERK phosphorylation. Furthermore, TMP and antioxidants such as Trolox and diphenylene iodonium decreased Ang II-induced ERK phosphorylation, and activator protein-1 reporter activity. In summary, we demonstrate for the first time that TMP inhibits Ang II-induced proliferation and ET-1, partially by interfering with the ERK pathway via attenuation of Ang II-increased NAD(P)H oxidase and ROS generation. Thus, this study delivers important new insight in the molecular pathways that may contribute to the proposed beneficial effects of TMP in cardiovascular disease.
Abstract. Alzheimer's disease (AD) is an age-related neurodegenerative disease, affecting over 20 million people worldwide. Until recently, two major hypotheses were proposed regarding the molecular mechanism of pathogenesis: the cholinergic hypothesis and the amyloid cascade hypothesis. At present, acetylcholinesterase inhibitors are the most effective therapy for AD. Most pharmacological research has focused on the ability of acetylcholinesterase to alleviate cholinergic deficit and improve neurotransmission. Coptidis rhizoma and its isolated alkaloids are reported to possess a variety of activities, including neuroprotective and antioxidant effects. However, as yet no theoretical analysis exists to support this hypothesis. To examine this theory, we applied a computational pharmaceutical analysis to reveal that Chinese medicine Coptidis rhizoma alkaloids have much higher activities than Donepezil (commercial name is Aricept) by docking and scoring.
The myocardial protective effects of trilinolein, isolated from the traditional Chinese herb Sanchi (Panax notoginseng), are thought to be related to its antioxidant activity. However, the intracellular mechanism underlying the protective effect of trilinolein in the heart remains unclear. In the present study, we investigated the effect of trilinolein on norepinephrine (NE)-induced protein synthesis in cardiomyocytes. Cultured neonatal rat cardiomyocytes were stimulated with NE, then protein content, [3H]-leucine incorporation, and β-myosin heavy chain (β-MyHC) promoter activity were examined. The effect of trilinolein on NE-induced intracellular reactive oxygen species (ROS) generation was measured with a redox- sensitive fluorescent dye (2′,7′-dichlorofluorescin diacetate) and extracellular signal-regulated kinase (ERK) phosphorylation by Western blotting. Trilinolein inhibited NE-increased protein synthesis, β-MyHC promoter activity, and intracellular ROS. Both trilinolein and the antioxidant, N-acetyl-cysteine, decreased NE- and H2O2-induced protein synthesis, β-MyHC promoter activity, and ERK phosphorylation. These data indicate that trilinolein inhibits NE-induced protein synthesis via attenuation of ROS generation in cardiomyocytes.
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