Recombinant human erythropoietin prevents cisplatin-induced genotoxicity in rat liver and heart tissues via an antioxidant process

Cisplatin (Cisp) is one of the most effective chemotherapeutic agents. However, at higher doses, liver and heart injuries may occur. Recombinant human erythropoietin (rhEPO) has recently been shown to exert an important cytoprotective effect in many tissues. For that reason, we tried to check the protective effect of rhEPO against Cisp-induced genotoxicity and oxidative stress in liver and heart tissues. Our experiments were performed using six groups of adult male Wistar rats. The control group was treated only with saline solution. The rhEPO group was given a single dose of rhEPO. The Cisp group was given a single injection of Cisp. The rhEPO+Cisp groups were given rhEPO simultaneously, 24 hours before, and 5 days after Cisp injection. Our results clearly showed that Cisp induced noticeable DNA damage in the liver and heart, accompanied by a significant increase in protein carbonyl level, reduced glutathione (GSH) depletion, and a decrease in catalase activity. Rats treated with rhEPO, simultaneously, before, or after Cisp injection, remarkably decreased DNA damage. It decreased also the protein carbonyl level, restored GSH depletion, and enhanced catalase activity. Our results highlight an interesting cytoprotective strategy using rhEPO against Cisp-induced liver and heart injuries.     

Protective effect of erythropoietin against cisplatin-induced nephrotoxicity in rats: antigenotoxic and antiapoptotic effect

Cisplatin (Cisp) is an active cytotoxic agent that was found efficient in the treatment of various types of solid tumors. Its nephrotoxic effect has been very well documented in clinical oncology. Erythropoietin (EPO), a renal cytokine-regulating hematopoiesis, has recently been shown to exert important cytoprotective effects in many experimental injuries. The aim of this study was to explore whether EPO would protect against Cisp-induced apoptosis in rat kidney. Adult Wistar rats were treated with saline solution as the control group, Cisp alone, EPO alone, or EPO with Cisp in different treatments: 1) EPO and Cisp simultaneously administrated to animals as a cotreatment; 2) EPO administered 24 hours before Cisp as a pretreatment; and 3) EPO administered 5 days after Cisp injection as a post-treatment. Our results have shown that Cisp induced renal failure, characterized with a significant increase in serum creatinine and blood urea nitrogen (BUN) concentrations. Cisp promoted kidney DNA fragmentation and apoptotic cell death. Apoptosis was revealed by an enhancement of proapoptotic protein (e.g., p53 and Bax) levels, decrease in antiapoptotic proteins (e.g., Bcl2 and Hsp27), and increase in caspase-3 activity. Treatments with EPO restored creatinine and BUN levels and inhibited Cisp-induced DNA damage in the kidney. Apoptosis was also reduced by the upregulation of antiapoptotic protein expressions, downregulation of proapoptotic protein levels, and reduction of caspase-3 activity.     

云芝多糖对脑、肝组织的抗氧化作用研究

目的　探讨中药云芝多糖对脑、肝组织抗氧化作用的影响及机制。方法　以SD大鼠和昆明小鼠为动物模型 ,采用Fe H2 O2 诱导大脑皮层组织和肝组织匀浆的脂氢过氧化反应及黄嘌呤氧化酶体系释放自由基超氧阴离子 (O·2 ) ,以改良的邻苯三酚自氧化法、DNTB直接法测定脑组织抗氧化酶活性及原位杂交法检测脑组织硒谷胱甘肽过氧化物酶 (SeG Px)mRNA表达。结果　云芝多糖有提高脑组织超氧化物歧化酶 (SOD)、SeGPx和非硒谷胱甘肽过氧化物酶 (non SeGPx)抗氧化酶活性 ,增加SeGPxmRNA表达 ,降低脑、肝组织Fe H2 O2 引发的脂氢过氧化反应和黄嘌呤氧化酶体系产生的O·2 。结论　云芝多糖可提高鼠大脑皮层、肝组织的抗氧化作用 ,对开发应用多糖类药物防治神经系统疾病、延缓衰老提供实验依据     

Safety of oligonol,a highly bioavailable lychee-derived polyphenolic antioxidant,on liver,kidney and heart function in rats

Oligonol (OLG), derived from lychee fruit, is a novel compound produced from the oligomerization of polyphenols. In this study, the acute effect of OLG treatment was investigated on heart, liver and kidney in rats. OLG treatment at two different doses (15 or 30?mg/kg body weight) and two different time points (1 day or 7 days of treatment) demonstrated that no toxic effects were observed on heart, liver and renal functions. Moreover, OLG did not induce any DNA damage or oxidative stress as measured by 8-hydroxy-2′-deoxyguanosine levels in plasma. OLG supplementation increased the phosphorylation of myocardial endothelial nitric oxide (NO) level (p-eNOS) in both the treatment groups. Even the low dose OLG treatment (15mg/kg b.w) demonstrated an increase in p-eNOS/eNOS ratio after normalization of p-eNOS values with eNOS on day 1 (1.5-fold) and day 7 (2.2-fold) groups as compared to control. The above results suggest that OLG treatment increases endothelial NO levels and may play a role in NO-mediated vasodilatory effects without adverse side effects on cardiovascular function. This endothelial NO production may underlie the beneficial effect of OLG in cardiovascular health.     

Selenium ameliorates isotretinoin-induced liver injury and dyslipidemia via antioxidant effect in rats

Isotretinoin (Iso) is a widely used retinoid for the treatment of dermatologic conditions. Although it has broad side effects, there is no well-designed study about preventive effects against its hepatic toxicity. This study was undertaken to evaluate the protective effect of selenium (Se) against Iso-induced hepatotoxicity in Wistar rats. Animals were divided into four groups. The first group served as control. The second, third and fourth groups received Se, Iso and Se &; Iso, respectively, for 28 days. Se was administered daily orally at a dose of 50?µg / 100?g body weight. Iso was given daily orally at a dose of 0.75?mg/ 100?g /day in olive oil. Iso caused significant increases in serum levels of alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, cholesterol, triglycerides, and high-density lipids content. Animals also showed significant rise in thiobarbituric acid reacting substance and nitric oxide content with concomitant decrease in reduced glutathione content and the antioxidant enzyme activities of superoxide dismutase and catalase in liver tissue after Iso exposure. Se administration produced a significant protection against the hepatotoxic effects of Iso and markedly alleviated alterations in these parameters. The results obtained herein clearly indicate that Iso causes induction of oxidative stress and the co-administration of Iso and Se provides protection against Iso-induced liver injury.     

知母宁对低氧高二氧化碳肺心病大鼠心肌、肝组织丙二醛和SOD含量的影响

目的:观察知母宁对慢性低O2高CO2肺心病大鼠心肌及肝脏组织超氧化物歧化酶(superox-ide dismutase,SOD)、丙二醛(malondialdehyde,MDA)的影响。方法:将SD大鼠分为正常对照组、4周低O2高CO2组(模型组)、4周低O2高CO2+知母宁组(知母宁组);制备慢性低O2高CO2肺心病大鼠模型,观察各组心肌、肝组织病理学改变;测定心肌、肝组织超氧化物歧化酶(SOD)、丙二醛(MDA)的含量。结果:光镜下模型组大鼠心肌损伤、肝组织脂肪变性明显,知母宁组上述改变不明显;模型组大鼠肝组织MDA较正常组显著升高,而SOD显著下降,知母宁组大鼠肝组织MDA较模型组显著降低,而SOD显著升高;模型组大鼠心肌组织MDA较正常组显著升高,而SOD显著下降,知母宁组大鼠心肌组织MDA较模型组显著降低,而SOD显著升高。结论:慢性低O2高CO2肺动脉高压状态下大鼠心肌、肝脏组织脂质过氧化增加,知母宁能减轻慢性低O2高CO2大鼠心肌、肝脏组织脂质过氧化作用。     

Chrysanthemi Flos extract alleviated acetaminophen-induced rat liver injury via inhibiting oxidative stress and apoptosis based on network pharmacology analysis

ContextAcetaminophen (APAP) overdose is the leading cause of drug-induced liver injury. Bianliang ziyu, a variety of Chrysanthemum morifolium Ramat. (Asteraceae), has potential hepatoprotective effect. However, the mechanism is not clear yet.ObjectiveTo investigate the hepatoprotective activity and mechanism of Bianliang ziyu flower ethanol extract (BZE) on APAP-induced rats based on network pharmacology.Materials and methodsPotential pathways of BZE were predicted by network pharmacology. Male Sprague-Dawley rats were pre-treated with BZE (110, 220 and 440 mg/kg, i.g.) for eight days, and then APAP (800 mg/kg, i.g.) was used to induce liver injury. After 24 h, serum and liver were collected for biochemical detection and western blot measurement.ResultsNetwork pharmacology indicated that liver-protective effect of BZE was associated with its antioxidant and anti-apoptotic efficacy. APAP-induced liver pathological change was alleviated, and elevated serum AST and ALT were reduced by BZE (440 mg/kg) (from 66.45 to 22.64 U/L and from 59.59 to 17.49 U/L, respectively). BZE (440 mg/kg) reduced the ROS to 65.50%, and upregulated SOD and GSH by 212.92% and 175.38%, respectively. In addition, BZE (440 mg/kg) increased levels of p-AMPK, p-GSK3β, HO-1 and NQO1, ranging from 1.66- to 10.29-fold compared to APAP group, and promoted nuclear translocation of Nrf2. BZE also inhibited apoptosis induced by APAP through the PI3K–Akt pathway and restored the ability of mitochondrial biogenesis.Discussion and conclusionsOur study demonstrated that BZE protected rats from APAP-induced liver injury through antioxidant and anti-apoptotic pathways, suggesting BZE could be further developed as a potential liver-protecting agent.     

Cisplatin impairs antioxidant system and causes oxidation in rat kidney tissues: possible protective roles of natural antioxidant foods

This study aims to elucidate the molecular mechanism(s) of cisplatin nephrotoxicity and the possible protective effects of antioxidant food supplementation on this toxicity. Twenty eight rats were used throughout the study. Cisplatin was administered intraperitoneally (i.p.) in a single dose (10 mg kg(-1)). Antioxidant food supplementation was started 3 days before cisplatin treatment. In each group (control, cisplatin, cisplatin plus dried black grape and cisplatin plus tomato juice), there were seven animals. Rats were killed 72 h after treatment. The kidneys were removed and prepared for biochemical and histopathological investigations. Oxidant (sensitivity to oxidation, xanthine oxidase enzyme and malondialdehyde level) and antioxidant (superoxide dismutase, glutathione peroxidase and catalase enzymes, and antioxidant potential value) parameters were measured in kidney tissues of the groups. Histopathological examination was also performed. Significant decreases were measured in the renal activities of catalase and glutathione peroxidase enzymes. There was, however, a significant increase in the activity of xanthine oxidase enzyme in the cisplatin-treated animals compared with the control group. The kidney tissue malondialdehyde levels were found to be increased, but sensitivity to oxidation and antioxidant potential values to be decreased in the cisplatin group. In the food supplemented groups, it has been observed that black grape eliminated oxidant stress by increasing antioxidant potential, but tomato did not. Histopathological examination results also revealed significant damage in the kidney tissues from the cisplatin-treated rats. In the black grape group, significant improvements were observed compared with the cisplatin group. In the tomato group, there were also some improvements but to a lesser degree compared with the black grape group. The results suggest that cisplatin treatment causes significant oxidant load to the kidneys through both xanthine oxidase activation and impaired antioxidant defense system, which resulted in accelerated oxidation reactions in the kidney tissue. It is proposed that supplementation of some foods such as black grape which has resveratrol as an antioxidant can provide significant protection against cisplatin nephrotoxicity.     

Rutin prevents cisplatin-induced ovarian damage via antioxidant activity and regulation of PTEN and FOXO3a phosphorylation in mouse model

The aims of the present study were to evaluate the protective effects of rutin during cisplatin-induced ovarian toxicity in mice and to verify the possible involvement of the phosphatase and tension homolog (PTEN)/Forkhead box O3a (FOXO3a) pathway in the rutin actions. Mice received saline solution (control, 0.15 M, i.p.) or cisplatin (5 mg/Kg body weight, i.p.) or they were pretreated with N-acetylcysteine (positive control; 150 mg/Kg of body weight [p.o.]) or with rutin (10, 30 or 50 mg/Kg body weight, p.o.) before cisplatin (5 mg/Kg body weight, i.p.) once daily for 3 days. Next, the ovaries were harvested and destined to histological (follicular morphology and activation), immunohistochemical (cell proliferation and apoptosis) and fluorescence (reactive oxygen species [ROS], glutathione [GSH] and mitochondrial activity) analyses. Moreover, the expression of phosphorylated PTEN (p-PTEN) and FOXO3a (p-FOXO3a) were evaluated to investigate a molecular mechanism by which rutin would prevent the cisplatin-induced ovarian damage. The results showed that pretreatment with N-acetylcysteine or 10 mg/Kg rutin before cisplatin preserved the percentage of normal follicles and cell proliferation, reduced apoptosis and ROS levels and increased active mitochondria and GSH levels compared to the cisplatin treatment (P < 0.05). Cisplatin treatment increased p-PTEN and decreased p-FOXO3a expression in follicles, which was prevented by 10 mg/kg rutin. In conclusion, treatment with 10 mg/Kg rutin has the potential to protect the ovarian follicles against cisplatin-induced toxicity through its antioxidant effects and PTEN/FOXO3a pathway.     

Rebaudioside A administration prevents experimental liver fibrosis: an in vivo and in vitro study of the mechanisms of action involved

Rebaudioside A (Reb A) is a diterpenoid isolated from the leaves of Stevia rebaudiana (Bertoni) that has been shown to possess pharmacological activity, including anti‐inflammatory and antioxidant properties. However, the ability of Reb A to prevent liver injury has not been evaluated. Therefore, we aimed to study the potential of Reb A (20 mg/kg; two times daily intraperitoneally) to prevent liver injury induced by thioacetamide (TAA) administration (200 mg/kg; three times per week intraperitoneally). In addition, cocultures were incubated with either lipopolysaccharide or ethanol. Antifibrotic, antioxidant and immunological responses were evaluated. Chronic TAA administration produced considerable liver damage and distorted the liver parenchyma with the presence of prominent thick bands of collagen. In addition, TAA upregulated the expression of α‐smooth muscle actin, transforming growth factor‐β1, metalloproteinases 9, 2 and 13, and nuclear factor kappaB and downregulated nuclear erythroid factor 2. Reb A administration prevented all of these changes. In cocultured cells, Reb A prevented the upregulation of genes implicated in fibrotic and inflammatory processes when cells were exposed to ethanol and lipopolysaccharide. Altogether, our results suggest that Reb A prevents liver damage by blocking oxidative processes via upregulation of nuclear erythroid factor 2, exerts immunomodulatory effects by downregulating the nuclear factor‐κB system and acts as an antifibrotic agent by maintaining collagen content.     

Isoproterenol effects evaluated in heart slices of human and rat in comparison to rat heart in vivo

Human response to isoproterenol induced cardiac injury was evaluated by gene and protein pathway changes in human heart slices, and compared to rat heart slices and rat heart in vivo. Isoproterenol (10 and 100 μM) altered human and rat heart slice markers of oxidative stress (ATP and GSH) at 24 h. In this in vivo rat study (0.5 mg/kg), serum troponin concentrations increased with lesion severity, minimal to mild necrosis at 24 and 48 h. In the rat and the human heart, isoproterenol altered pathways for apoptosis/necrosis, stress/energy, inflammation, and remodeling/fibrosis. The rat and human heart slices were in an apoptotic phase, while the in vivo rat heart exhibited necrosis histologically and further progression of tissue remodeling. In human heart slices genes for several heat shock 70 kD members were altered, indicative of stress to mitigate apoptosis. The stress response included alterations in energy utilization, fatty acid processing, and the up-regulation of inducible nitric oxide synthase, a marker of increased oxidative stress in both species. Inflammation markers linked with remodeling included IL-1α, Il-1β, IL-6 and TNFα in both species. Tissue remodeling changes in both species included increases in the TIMP proteins, inhibitors of matrix degradation, the gene/protein of IL-4 linked with cardiac fibrosis, and the gene Ccl7 a chemokine that induces collagen synthesis, and Reg3b a growth factor for cardiac repair. This study demonstrates that the initial human heart slice response to isoproterenol cardiac injury results in apoptosis, stress/energy status, inflammation and tissue remodeling at concentrations similar to that in rat heart slices.     

Caffeic acid prevents liver damage and ameliorates liver fibrosis induced by CCI4 in the rat

It has been postulated that during liver damage there is an arachidonic acid metabolism deflection toward lipoxygenase products and a simultaneous decrement of the synthesis of cytoprotective prostaglandins. Accordingly, we have demonstrated that leukotriene synthesis inhibition protects the liver from acute damage induced by CCI₄. Thus, the aim of the present work was to study the effect of caffeic acid (a specific 5-lipoxygenase inhibitor) on liver cirrhosis induced by CCI₄ administration in the rat. Caffeic acid prevented significantly the increment of serum markers of liver damage, as well as lipid peroxidation and the depletion in glycogen content of the liver induced by chronic CCI₄ intoxication. Collagen content increased fivefold in the CCI₄-treated rats. The group treated with the lipoxygenase inhibitor, in addition to CCI₄, showed less collagen content than the group receiving only CCI₄ (P ? .05). Caffeic acid prevented liver damage significantly. The hepatoprotective effect of this compound could be attributed to its ability to inhibit 5-lipoxygenase activity, and thus leukotriene production. © 1995 Wiley-Liss, Inc.     

Anti‐ischaemic activity of an antioxidant aldose reductase inhibitor on diabetic and non‐diabetic rat hearts

Objectives Many observations report the cardioprotective effects of inhibitors of aldose reductase in different models of ischaemia–reperfusion injury in diabetic myocardium. In this paper, the inhibitory effects of the new pyrido[1,2‐a]‐pyrimidin‐4‐one derivative PPO, whose aldose reductase‐inhibitory and antioxidant effects were shown in a previous study, were evaluated. Methods The effect of PPO was evaluated on aldose reductase from hearts of diabetic and non‐diabetic rats, and compared with that of the reference drug epalrestat. Moreover, the two drugs were tested on isolated and Langendorff‐perfused diabetic and non‐diabetic hearts submitted to ischaemia–reperfusion cycle. Key findings Epalrestat showed equivalent levels of potency in inhibiting the activity of the enzyme in the diabetic and in the non‐diabetic hearts. On the contrary, the inhibitory potency of PPO was decreased in the diabetic organs. In the diabetic hearts submitted to ischaemia–reperfusion, an increased level of heart aldose reductase activity was recorded, and both PPO and epalrestat produced cardioprotective effects, suggesting that aldose reductase is deeply involved in the process of ischaemia–reperfusion injury in diabetic myocardium. In non‐diabetic hearts, where aldose reductase has a lower activity, epalrestat failed to produce significant protection, while PPO still maintained cardioprotective effects, which may be reasonably attributed to useful ‘ancillary’ effects – such as antioxidant activity – independent from the aldose reductase inhibition. Conclusions Therefore PPO, a new molecule endowed with both aldose reductase‐inhibitory effects and antioxidant activity, may represent the prototype of a new class of multitarget drugs, focused on two different steps deeply involved in the pathogenesis of ischaemic injury of diabetic hearts.     

Organophosphate pesticides‐induced changes in the redox status of rat tissues and protective effects of antioxidant vitamins

Organophosphates (OPs) pesticides are among the most toxic synthetic chemicals purposefully added in the environment. The common use of OP insecticides in public health and agriculture results in an environmental pollution and a number of acute and chronic poisoning events. Present study was aimed to evaluate the potential of monocrotophos and quinalphos to effect the redox status and glutathione (GSH) homeostasis in rat tissues and find out whether antioxidant vitamins have some protection on the pesticide‐induced alterations. The results showed that these pesticides alone or in combination, caused decrease in the levels of GSH and the corresponding increase in the levels of GSSG, decreasing the GSH/GSSG ratio. The results also showed that NADPH/NADP⁺ and NADH/NAD⁺ ratios were decreased in the liver and brain of rats on exposure with mococrotophos, quinalphos, and their mixture. These pesticides, alone or in combination, caused alterations in the activities of GSH reductase and glucose‐6‐phosphate dehydrogenase in the rat tissues. However, the expression of the GSH recycling enzymes did not show significant alterations as compared to control. From the results, it can be concluded that these pesticides generate oxidative stress but their effects were not synergistic when given together and prior feeding of antioxidant vitamins tend to reduce the toxicities of these pesticides. © 2013 Wiley Periodicals, Inc. Environ Toxicol 30: 472–482, 2015.     

Effects of diazinon on antioxidant defense system and lipid peroxidation in the liver of Cyprinus carpio (L.)

Diazinon is a widely used organophosphorus pesticide in agriculture and environmental health, hence its adverse effects on nontarget animals, especially on fish is to be determined. The present study therefore aimed at detecting the biochemical changes caused by diazinon. To accomplish this aim, we studied the effects of sublethal concentrations (0.0036, 0.018, and 0.036 ppb) of diazinon on acetylcholine esterase activity, antioxidant enzyme activities, and lipid peroxidation in the liver of Cyprinus carpio on days 5, 15, and 30 after the exposure. The results revealed that the antioxidant enzyme activities such as superoxide dismutase, glutathione peroxidase, and catalase were induced by diazinon exposure. In addition, the highest catalytic activity of glutathione S‐transferase (GST) was obtained with 1‐chloro‐2, 4‐dinitrobenzene (CDNB). GST activity toward 1,2‐dichloro‐4‐nitrobenzene (DCNB) was also observed in the liver, yet it was relatively low as opposed to the other substrates tested. On the other hand, hepatic malondialdehyde level did not show any significant alteration except after the exposure on day 15. The exposure of low concentrations of diazinon to C. carpio can induce oxidative stress in liver; yet restoring susceptibility and adapting to oxidative stress are likely to occur when low level of oxidative stress is administered. Furthermore, no significant change was observed in hepatic lipid peroxidation after diazinon treatment indicating that liver tissue resisted to oxidative stress by enhancing their antioxidant mechanisms. The level of lipid peroxidation was assumed to be associated with the concentrations of diazinon and experimentation periods. The induction of glutathione S‐transferase and antioxidant enzyme activities were also assumed to have resulted from the defense against the toxicity of diazinon. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2011.     

Metallothionein induction in the liver, kidney, heart and aorta of cadmium and isoproterenol treated rats

Metallothionein (MT), induced in different organs in response to heavy metals and oxidative conditions, exerts antioxidant properties and thus could be implicated in cardiovascular physiopathology. The aim of this study was to investigate the capacity of cadmium (Cd) and isoproterenol to induce in vivo MT not only in rat liver and kidneys but also in heart and aorta. Tissue MT levels, catalase (CAT) and glutathione peroxidase (GPX) activities were assayed at different times after Cd or isoproterenol injection. Cd induced a dose-dependent induction of MT with a higher response in the liver than in the kidney, aorta and heart. The hepatic increase was early (12 h) and maintained (72 h), whereas the elevation was maximal around 48 h for the other organs. Isoproterenol induced a transient (12 h) hepatic and a biphasic (12 and 36 h) renal and cardiac increase. CAT activity was decreased in the liver and increased in the heart with the higher Cd doses. Isoproterenol increased the cardiac GPX activity. In conclusion, the results demonstrate that MT can be induced in rat liver and kidneys but also in heart after a Cd or isoproterenol injection. This enhancement of cardiac and vascular MT levels could be used to study the potential protective effect of MT in cardiovascular diseases.     

P2 purinergic receptor mRNA in rat and human sinoatrial node and other heart regions

It is known that adenosine 5′-triphosphate (ATP) is a cotransmitter in the heart. Additionally, ATP is released from ischemic and hypoxic myocytes. Therefore, cardiac-derived sources of ATP have the potential to modify cardiac function. ATP activates P2X_1–7 and P2Y_1–14 receptors; however, the presence of P2X and P2Y receptor subtypes in strategic cardiac locations such as the sinoatrial node has not been determined. An understanding of P2X and P2Y receptor localization would facilitate investigation of purine receptor function in the heart. Therefore, we used quantitative PCR and in situ hybridization to measure the expression of mRNA of all known purine receptors in rat left ventricle, right atrium and sinoatrial node (SAN), and human right atrium and SAN. Expression of mRNA for all the cloned P2 receptors was observed in the ventricles, atria, and SAN of the rat. However, their abundance varied in different regions of the heart. P2X₅ was the most abundant of the P2X receptors in all three regions of the rat heart. In rat left ventricle, P2Y₁, P2Y₂, and P2Y₁₄ mRNA levels were highest for P2Y receptors, while in right atrium and SAN, P2Y₂ and P2Y₁₄ levels were highest, respectively. We extended these studies to investigate P2X₄ receptor mRNA in heart from rats with coronary artery ligation-induced heart failure. P2X₄ receptor mRNA was upregulated by 93% in SAN (P < 0.05), while a trend towards an increase was also observed in the right atrium and left ventricle (not significant). Thus, P2X₄-mediated effects might be modulated in heart failure. mRNA for P2X_4–7 and P2Y_{1,2,4,6,12–14}, but not P2X_2,3 and P2Y₁₁, was detected in human right atrium and SAN. In addition, mRNA for P2X₁ was detected in human SAN but not human right atrium. In human right atrium and SAN, P2X₄ and P2X₇ mRNA was the highest for P2X receptors. P2Y₁ and P2Y₂ mRNA were the most abundant for P2Y receptors in the right atrium, while P2Y₁, P2Y₂, and P2Y₁₄ were the most abundant P2Y receptor subtypes in human SAN. This study shows a widespread distribution of P2 receptor mRNA in rat heart tissues but a more restricted presence and distribution of P2 receptor mRNA in human atrium and SAN. This study provides further direction for the elucidation of P2 receptor modulation of heart rate and contractility. Mark R. Boyett and Halina Dobrzynski are joint senior authors.     

Biotransformation of cyclosporin in primary rat,porcine and human liver cell co-cultures

The purpose of this study was to investigate the species-specific cyclosporin biotransformation in primary rat, human, and porcine liver cell cultures, and to investigate the suitability of a modified sandwich culture technique with non-purified liver cell co-cultures for drug metabolism studies. A sandwich culture was found to enhance hepatocellular metabolic activity and improve cellular morphology and ultrastructure. The cyclosporin metabolites AM9 and AM1 were formed in porcine and human liver cell sandwich co-cultures at levels corresponding to the respective in vivo situations. In contrast, metabolite profiles in rat hepatocytes were at variance with the in vivo situation. However, for all cell types, the overall metabolic activity was positively influenced by sandwich co-culture. The initial levels of albumin synthesis were higher in sandwich cultures than in those without matrix overlay. It is hypothesized that the sandwich culture system provides an improved microenvironment and is, therefore, an advantageous tool for in vitro studies of drug metabolism.     

外源性一氧化氮对大鼠肝脏抗氧化物酶和药物代谢酶活性的影响

用亚硝基铁氰化钠(SNP)作为NO生成前体,以 0, 1, 2, 4 和 8 mg·kg^-1 ip 给予大鼠,每日一次,连续 5 d,来研究外源性NO对大鼠肝脏细胞色素 P450, 苯胺羟化酶(AH), 谷胱甘肽S-转移酶(GST)等药物代谢酶和过氧化氢酶(Cat), 谷胱甘肽过氧化物酶(GSH-Px), 超氧化物歧化酶(SOD)等抗氧化物酶活性以及脂质过氧化的体内影响情况. 结果表明外源性NO能明显降低大鼠肝脏SOD, Cat, AH 的活性和细胞色素P450的含量(P<0.05),并且高剂量组还能明显促进脂质过氧化发生(P<0.05), 但对GSH-Px和GST的活性则无明显影响.     

Ginger extract modulates Pb-induced hepatic oxidative stress and expression of antioxidant gene transcripts in rat liver

Context: Spices and herbs are recognized sources of natural antioxidants that can protect from oxidative stress, thus play an important role in chemoprevention of liver diseases. Ginger is used worldwide primarily as a spicy condiment.

Objective: This study evaluated the ability of ginger extract (GE) to ameliorate oxidative-hepatic toxicity induced by lead acetate (PbAc) in rats.

Materials and methods: Five groups of animals were used: group I kept as control; groups II, IV, and V received PbAc (1?ppm in drinking water daily for 6 weeks, and kept for an additional 2 weeks without PbAc exposure); group III treated orally with GE (350?mg/kg body weight, 4?d per week) for 6 weeks; group IV (protective) received GE for 2 weeks before and simultaneously with PbAc; and group V (treatment) received GE for 2 weeks after PbAc exposure.

Results: GC-MS analysis of GE revealed its content of gingerol (7.09%), quercetin (3.20%), dl-limonene (0.96%), and zingiberene (0.18%). Treatment of PbAc-treated rats with GE has no effect on hepatic Pb concentrations. However, it maintained serum aspartate aminotransferase level, increased hepatic glutathione (157%), glutathione S-transferase (GST) (228%), glutathione peroxidase (GPx) (138%) and catalase (CAT) (112%) levels, and reduced hepatic malondialdehyde (80%). Co-treatment of PbAc group with GE upregulated mRNA expression of antioxidant genes: GST-α1 (1.4-fold), GPx1 (1.8-fold), and CAT (8-fold), while post-treatment with GE upregulated only mRNA expression of GPx1 (1.5-fold).

Conclusion: GE has an antioxidant protective efficacy against PbAc-induced hepatotoxicity, which appears more effective than its therapeutic application. However, the changes in antioxidant gene expression were not reflected at the protein level.