阿魏酸钠对乙醇所致小鼠肝脏抗氧化功能改变的拮抗作用

研究了不同剂量乙醇对小鼠抗氧化和解毒功能的影响以及阿魏酸钠的拮抗作用。结果表明,大剂量乙醇(11.4g·kg^-1ig)引起肝脏GSH-Px活性升高的同时,肝脏GSH-Re,SOD和GST活性降低,GSH耗竭,而血清GST升高;阿魏酸钠(100mg·kg^-1ig,qd×10)预处理则明显拮抗大剂量乙醇所致的上述改变。表明阿魏酸钠对急性乙醇所致肝损害具有良好保护作用,其机理可能与提高GSH氧化还原酶功能、增加SOD活性和增强GSH结合反应有关。研究结果还提示,血清GST水平是反映乙醇性肝损害的灵敏指标。     

槲皮素对阿霉素致小鼠心肌损伤的保护作用及其机制

观察槲皮素对阿霉素致小鼠心肌损伤的保护作用并初步探讨其机制。腹腔注射阿霉素(20 mg·kg^-1)复制小鼠心肌损伤模型，检测心电图、心肌超微结构，血清NO含量和iNOS活性，心肌组织LDH、SOD、MDA的水平和p53蛋白表达。并观察槲皮素(50，100及200 mg·kg^-1)对上述指标的影响。阿霉素可导致小鼠心律失常和心肌超微结构损伤；使NO、iNOS、MDA和LDH的水平升高，SOD的水平降低；p53蛋白表达增强。槲皮素(50，100及200 mg·kg^-1)可拮抗阿霉素所致的上述变化。槲皮素对阿霉素性小鼠心肌损伤具有保护作用，其机制与增强SOD活力、降低iNOS活性、抑制p53蛋白表达等有关。     

黄芪多糖对内毒素致小鼠毒性损伤的作用

本文结果表明,预先给予黄芪多糖(APS)ip30,60,100mg·kg^-1·d^-1×7d能明显提高内毒素(25mg·kg^-1·ip)中毒小鼠的存活率,APSip 100mg·kg^-1·d^-1×7d,能完全解除内毒素的致死作用,对内毒素中毒鼠肝脏内ATP含量及EC值下降具有拮抗作用。上述作用均呈剂量依赖性。APSip 60,100mg·kg^-1·d^-1×7d能明显拮抗内毒素处理小鼠肝匀浆中MDA升高及GSH降低。电镜显示APS对内毒素处理小鼠肝脏线粒体结构的损伤具有保护作用。     

氧化苦参碱对病毒性心肌炎小鼠心肌细胞凋亡及相关因子的影响

目的 探讨氧化苦参碱(oxymatrine,OMT)对病毒性心肌炎小鼠心肌细胞凋亡及其凋亡相关因子蛋白表达的影响。方法 42只BALB/c小鼠随机分为正常对照组(NC)、病毒性心肌炎模型组(VM)、OMT高剂量组(OMT-H,25?mg·kg^-1·d^-1)、OMT中剂量组(OMT-M,12.5 mg·kg^-1·d^-1)、OMT低剂量组(OMT-L,6.25 mg·kg^-1·d^-1)、OMT极低剂量组(OMT-EL,3.125 mg·kg^-1·d^-1)、利巴韦林对照组(RB,100 mg·kg^-1·d^-1)。病毒性心肌炎小鼠由柯萨奇病毒B3型腹腔注射感染所致,各治疗组从末次给予病毒24 h后开始,腹腔注射,每日1次。于治疗第12天,每组处死小鼠6只,留取心肌标本。TUNEL法检测心肌细胞凋亡情况,免疫印迹法和免疫组织化学法检测Bcl-2和Bax蛋白的表达情况。结果 OMT治疗显著降低了病毒性心肌炎小鼠凋亡心肌细胞的数量,与病毒性心肌炎模型组比较,OMT-L组效果最佳(P<0.01)。与病毒性心肌炎模型组小鼠比较,OMT治疗组的小鼠心肌组织中Bax蛋白表达降低,而Bcl-2蛋白表达没有明显改变。结论 氧化苦参碱可减少病毒性心肌炎小鼠心肌细胞的凋亡,该作用与下调Bax蛋白表达有关。     

双环醇对四环素诱发小鼠急性脂肪肝的保护作用

研究双环醇对四环素诱发小鼠急性脂肪肝的影响。小鼠一次腹腔注射四环素(180 mg·kg^-1) 24 h后，收集血样和肝组织，采用生化法测定肝脏甘油三酯(triglyceride，TG)、胆固醇(cholesterol，CHO)、谷胱甘肽(glutathione，GSH)含量，以及血清脂质和转氨酶水平；光谱法测定小鼠线粒体脂肪酸β-氧化速率以及肝脏极低密度脂蛋白(very low density lipoprotein，VLDL，TG)分泌速率。结果表明，双环醇(150及300 mg·kg^-1)连续灌胃给药3次可以不同程度地保护四环素引起的小鼠肝脏TG和CHO升高以及血清谷丙转氨酶(alanine aminotransferase，ALT)、谷草转氨酶(aspartate aminotransferase，AST)升高和脂质异常。双环醇(300 mg·kg^-1)还可减轻四环素诱发小鼠肝脏丙二醛(malondialdehyde，MDA)生成增加和GSH水平降低，并能抑制肝线粒体脂肪酸β-氧化速率下降。双环醇(300 mg·kg^-1)可部分逆转四环素所致小鼠肝脏VLDL(TG)分泌速率的减少。由此可见，双环醇对四环素诱发小鼠急性脂肪肝具有明显的保护作用，其作用机制与保护肝线粒体β-氧化功能、改善肝脂蛋白分泌及转运以及抑制肝脏脂质过氧化密切相关。     

阿魏酸钠部分减轻氢化泼尼松引起的小鼠肝脏毒性

氢化泼尼松(Pred)20mg·kg^-1可明显增高小鼠sGPT与sGST水平,增加肝匀浆MDA含量及肝微粒体与线粒体膜流动性。表明Pred致sGPT及sGST水平增高与肝脂质过氧化作用增强及膜流动性改变有关。经1g阿魏酸钠(SF)100mg·kg^-1使sGPT与sGST水平降低,肝脏MDA含量减少,但sGPT与MDA仍高于正常对照组水平。肝微粒体膜流动性恢复,线粒体膜流动性进一步增高。电镜观察亦见线粒体仍有损害,提示SF不能完全对抗Pred所致肝损害。     

丙酮酸乙酯对利福平致小鼠肝损伤的保护作用

目的 探讨丙酮酸乙酯（EP）对利福平致小鼠肝损伤的保护作用及其可能机制。方法 24只C57BL/6小鼠随机分成3组：正常对照组、模型组（利福平,200 mg·kg^-1·d^-1） 和EP组（利福平200 mg·kg^-1·d^-1+丙酮酸乙酯40 mg·kg^-1·d^-1）,每组8只。造模后第7天处死小鼠,检测小鼠血清谷丙转氨酶（ALT）、总胆红素（TBIL）、直接胆红素（DBIL）、碱性磷酸酶（ALP）,观察小鼠肝脏病理学变化,检测小鼠肝组织总胆汁酸（TBA）、丙二醛（MDA）的含量、超氧化物歧化酶（SOD）活性、高迁移率族蛋白B1 （HMGB1） 及乙酰化的HMGB1（AC-HMGB1）蛋白的表达情况。结果 与正常对照组相比,模型组小鼠血清TBIL、DBIL、ALP、ALT水平升高（P<0.05）;肝细胞空泡变性、脂肪变性明显,部分肝细胞可见嗜酸性变、核溶解或固缩;肝组织TBA、MDA的含量提高（P<0.05）,SOD减少（P<0.05）,HMGB1及AC-HMGB1表达增多（P<0.05）,HMGB1胞浆表达为主。与模型组相比,EP组小鼠血清TBIL、DBIL、ALP、ALT水平降低（P<0.05）;肝组织病理学变化改善;肝组织TBA、MDA的含量降低（P<0.05）, SOD增多（P<0.05）,HMGB1及AC-HMGB1的表达水平降低（P<0.05）,HMGB1以胞核表达为主。结论 丙酮酸乙酯能够减轻利福平所致的小鼠肝损伤,其机制可能与丙酮酸乙酯抗氧化,下调肝组织HMGB1及AC-HMGB1的表达和调节HMGB1的分布有关。     

百香果果汁对D-半乳糖致衰老小鼠抗氧化作用的研究

摘 要 目的：观察不同浓度百香果果汁对D 半乳糖致衰老小鼠肝脏、心脏抗氧化作用的影响。方法: 将小鼠随机分为6组：正常对照组、模型对照组、阳性对照组（维生素C,100 mg·kg^-1）、百香果果汁低、中、高浓度组,每组8只。除正常对照组外,其余各组小鼠腹腔注射 D 半乳糖（100 mg·kg^-1）建立亚急性衰老模型,正常对照组腹腔注射等量的生理盐水,1次/d,连续42 d。造模的同时,百香果果汁治疗组小鼠分别按高、中、低浓度均灌胃给予10 ml·kg^-1相应浓度的百香果果汁,阳性对照组小鼠按100 mg·kg^-1灌胃给予维生素C,模型对照组和正常对照组均灌胃给予10 ml·kg^-1的生理盐水。给药结束后测定各组小鼠肝脏中过氧化氢酶（CAT)、谷胱甘肽（GSH)、超氧化物歧化酶（SOD）和丙二醛（MDA) 的含量;心脏中总抗氧化活力（T AOC）、SOD和MDA的含量。结果:百香果果汁治疗组能把衰老小鼠的体质量维持在一定水平,与阳性对照组比较差异无统计学意义（P＞0.05）。与模型对照组比较,百香果果汁低、中、高3种浓度组小鼠肝组织中CAT、GSH、SOD活性均明显升高,MDA明显下降,差异有统计学意义（P＜0.05或P＜0.01）,小鼠心脏组织中的T-ADC和SOD活性均明显升高,MDA含量均明显下降,除T-AOC指标的百香果果汁低浓度组外,差异有统计学意义（P＜0.01）。结论:百香果果汁有延缓D 半乳糖致衰老小鼠的作用,其机制可能与提高小鼠肝脏、心脏的抗氧化能力有关。     

甘草类黄酮对四氯化碳致小鼠急性肝损伤的影响

甘草类黄酮(GF)是从甘草根中提得。本文结果表明,预先ig GF 200,400,600mg·kg^-1·d^-1×2d能显著降低CCl₄所致血清谷丙转氨酶,乳酸脱氢酶活性的升高以及肝内丙二醛含量的增加,其作用呈剂量依赖性。GF可减轻CCl₄所致的肝脏坏死,但对血清内酶的活性没有抑制作用,也不减少正常小鼠血清中酶的活性。GF的肝保护作用可能与其抗脂质过氧化作用有关。     

甘草酸单铵对脂多糖致小鼠急性肺损伤的保护作用

采用脂多糖(lipopolysaccharide，LPS)气道滴入诱导小鼠急性肺损伤(acute lung injury，ALI)模型，研究甘草酸单铵(monoammonium glycyrrhizinate，MAG)对ALI的防治作用及其机制。雄性ICR小鼠随机分为生理盐水(NS)对照组、MAG 3、10 及30 mg·kg^-1组、LPS组、地塞米松(dexamethasone，DXM) 5 mg·kg^-1组。MAG各组气道滴入LPS前1 h及滴入后3 h各给药1次，DXM组气道滴入LPS前1 h给药1次。LPS气道滴入后6 h处死动物，测定各组的肺湿重/干重比、肺通透性、肺组织中性粒细胞髓过氧化物酶(myeloperoxidase，MPO)含量、ELISA法检测肺组织匀浆TNF-α、IL-10含量，常规细胞形态学检测中性粒细胞在支气管肺泡灌洗液(bronchoalveolar lavage fluid，BALF)中的比例和肺组织病理改变。结果表明，MAG剂量依赖性减轻气道内滴入LPS诱导的小鼠ALI程度，降低肺湿重/干重比及肺组织伊文斯蓝的渗出，降低BALF中白细胞总数和中性粒细胞数比例，抑制组织MPO的释放，降低肺组织匀浆TNF-α的含量，增加肺组织IL-10的释放。以上结果提示，MAG可能通过调节TNF-α/IL-10的平衡而有效保护脂多糖诱导的急性肺损伤。     

Protective effects of L-carnitine on myoglobinuric acute renal failure in rats

1. Muscle injury (rhabdomyolysis) is one of the causes of acute renal failure (ARF). Iron, free radicals and nitric oxide (NO) play a critical role in the pathogenesis of glycerol-induced myoglobinuric ARF. L-Carnitine is an anti-oxidant and prevents the accumulation of end-products of lipid peroxidation. Therefore, the aim of the present study was to investigate the effects of L-carnitine on myoglobinuric ARF induced by intramuscular (i.m.) hypertonic glycerol injection. 2. Sprague-Dawley rats were divided into three groups. Rats in group 1 (n = 8) were given saline, whereas those in groups 2 (n = 10) and 3 (n = 10) were injected with glycerol (10 mL/kg, i.m.). Concomitant with and 24 h after glycerol injection, L-carnitine (200 mg/kg, i.p.) was administered to group 3 rats. Forty-eight hours after glycerol injection, blood samples and kidney tissues were taken from anaesthetised rats. 3. Plasma creatine kinase (CK) activity, urea, creatinine and NO levels, as well as kidney tissue superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) enzyme activity and malondialdehyde (MDA) and glutathione (GSH) levels, were determined. In the kidney tissue, histopathological changes and iron accumulation in the tubular epithelium were also investigated. 4. Glycerol treatment caused severe ARF: a marked renal oxidative stress, significantly increased CK activity, urea and creatinine levels and decreased plasma NO levels. Histopathological findings in group 2 rats confirmed that there was renal impairment by cast formation and tubular necrosis and a marked increase in iron accumulation in the tubular epithelium. All these factors were significantly improved by L-carnitine supplementation. 5. These results may indicate that L-carnitine treatment protects against functional, biochemical and morphological damage and iron accumulation in glycerol-induced myoglobinuric ARF in rats. In this model, the protective effect of L-carnitine treatment may provide a new insight into the treatment of rhabdomyolysis-related ARF.     

Attenuation of glycerol-induced acute renal failure in rats by trimetazidine and deferoxamine

The pathogenesis of glycerol-induced myoglobinuric acute renal failure involves, among other causes, ischaemia, vascular congestion, and reactive oxygen metabolites. The aim of this study was to investigate the roles of ischaemia and iron-induced oxidative stress by employing trimetazidine, an anti-ischemic drug with an additional antioxidant effect, and deferoxamine, an iron chelator, in glycerol-induced acute renal failure in rats. Five groups of rats were employed in this study: group 1 served as control group, group 2 was given 50% glycerol alone (8 ml/kg i.m.), group 3 was given glycerol plus trimetazidine (3 mg/kg), and groups 4 and 5 were given glycerol plus deferoxamine (50 and 100 mg/kg, respectively). Renal injury was assessed by measuring plasma creatinine and blood urea nitrogen levels and creatinine and urea clearances. The oxidative stress was measured on the basis of the renal malondialdehyde and reduced glutathione levels and the activities of catalase, glutathione reductase, and superoxide dismutase. Glycerol treatment resulted in marked renal oxidative stress and deranged renal functions which significantly improved by trimetazidine and deferoxamine treatments. Deferoxamine, by interacting with Fenton reaction chemistry, and trimetazidine, by its anti-ischaemic and antioxidative properties, protected the kidney against the oxidative stress and the resultant renal dysfunction produced by glycerol. Based on these results, this study points towards renal ischaemia and iron as potential mediators and demonstrates the potential beneficial effects of deferoxamine and trimetazidine in glycerol-induced acute renal failure in rats.     

Protective effect of naringin, a bioflavonoid on glycerol-induced acute renal failure in rat kidney

Rhabdomyolysis-induced myoglobinuric acute renal failure accounts for about 10-40% of all cases of acute renal failure (ARF). Reactive oxygen intermediates have been demonstrated to play an etiological role in myoglobinuric renal failure. This study was designed to investigate the effect of naringin, a bioflavonoid with antioxidant potential, in glycerol-induced ARF in rats. Five groups of rats were employed in this study, group I served as control, group II was given 50% glycerol (8 ml/kg, intramuscularly), group III, IV, and V were given glycerol plus naringin 100, 200, and 400mg/kg p.o. route, respectively) 60 min prior to the glycerol injection. Renal injury was assessed by measuring plasma creatinine, blood urea nitrogen, creatinine, and urea clearance. The oxidative stress was measured by renal malondialdehyde levels, reduced glutathione levels, and by enzymatic activity of catalase, glutathione reductase, and superoxide dismutase. Glycerol treatment resulted in a marked renal oxidative stress and significantly deranged the renal functions. Pretreatment of animals with naringin 60 min prior to glycerol injection markedly attenuated renal dysfunction, morphological alterations, reduced elevated thiobarbituric acid reacting substances (TBARS), and restored the depleted renal antioxidant enzymes. These results clearly demonstrate the role of oxidative stress and its relation to renal dysfunction, and suggest a protective effect of naringin in glycerol-induced renal failure in rats.     

Regional haemodynamic effects of dopamine and its prodrugs L-dopa and gludopa in the rat and in the glycerol-treated rat as a model for acute renal failure.

1. In this study the renal selectivity of dopamine and its prodrugs L-dopa and gludopa, with respect to their effects on regional blood flow, vascular resistance and central haemodynamics was investigated in normal rats and in rats with glycerol-induced acute renal failure (ARF). 2. In normal, anaesthetized rats, dopamine as well as its prodrugs caused a dose-dependent reduction of vascular resistance in the kidney (RR), mesentery (MR) and hindquarters (HQR) (dose range: dopamine: 0.1-5 mumol kg-1 h-1; L-dopa and gludopa: 1-200 mumol kg-1 h-1). Blood pressure and heart rate were affected at the highest dose only. 3. Administration of glycerol induced a preferential renal vasoconstriction; renal blood flow (-60%) and vascular resistance (+190%) were significantly more affected than MR (+40%) and HQR (+60%). This was only ameliorated by a low rate (10 mumol kg-1 h-1) infusion of gludopa: the glycerol-induced reduction of renal flow and increase in RR were significantly attenuated. A high dose of gludopa (100 mumol kg-1 h-1) or any dose of L-dopa or dopamine did not induce this beneficial effect. The glycerol-induced increase in MR and HQR was not attenuated by any of the treatments used. 4. The results indicate that gludopa is not renally selective at a pharmacodynamic level in normal, anaesthetized rats. Contrary to this, a low dose of gludopa does cause a renal selective vasodilatation and reduction of RR in rats with glycerol-induced ARF. This difference could be explained by a difference in renal vascular tone between normal rats and glycerol-induced ARF rats.(ABSTRACT TRUNCATED AT 250 WORDS)     

Further characterization of the protective effect of 8-cyclopentyl-1,3-dipropylxanthine on glycerol-induced acute renal failure in the rat.

In the rat, treatment with the alkylxanthine 8-cyclopentyl-1,3-dipropylxanthine (CPX) at a dose of 0.1 mg kg-1 antagonizes adenosine-induced falls in renal blood flow and reduces the severity of glycerol-induced acute renal failure. Treatment of glycerol-injected rats with 0.03 mg kg-1 of CPX resulted in no significant improvements in a range of indices of renal function. However, treatment with 0.1 or 0.3 mg kg-1 doses of CPX did significantly ameliorate acute renal failure although there were no significant differences in the degree of protection of renal function afforded by these two doses. In glycerol-injected rats, 0.1 or 0.3 mg kg-1 CPX administered either as a single dose or repeated doses every 12 h for two days did not inhibit renal phosphodiesterase. Thus the beneficial effects of CPX can be produced by doses that have no effect on renal phosphodiesterase activity whereas 0.1 mg kg-1 of CPX has been shown previously to antagonize the actions of adenosine. The findings provide further evidence that the beneficial effect of CPX in glycerol-induced acute renal failure is a consequence of adenosine antagonism and not phosphodiesterase inhibition.     

异搏定对肾脏功能和形态的保护作用

本实验观察了家兔甘油性急性肾功能衰竭时异博定对肾脏功能和形状的保护作用。结果表明,异博定能增加肌酐清除率,降低血尿素氮和滤过钠排泄分数,可以保护肾小球、肾小管的细胞结构,有防治急性肾功能衰竭的作用。伤前和伤后立即给药效果好,其机制与异搏定增加肾小球滤过率、保护小管细胞的功能等因素有关。     

Protective effect of γ-aminobutyric acid against glycerol-induced acute renal failure in rats

To investigate the effect of γ-aminobutyric acid (GABA) on acute renal failure, we used a rat model of acute tubular necrosis induced by glycerol. After deprivation of water for 6 h, the rats received an injection of 50% glycerol into the muscle of the rear limb at 10 ml/kg body weight. GABA was then administered orally to the rats (100 or 500 mg/kg body weight/day) once every 12 h for 3 days. The rats with acute renal failure showed arrested body weight gain and an increase of kidney weight, whereas oral administration of GABA attenuated the physiological changes induced by acute renal failure. However, GABA administration had no significant effect on increased urine volume. Oral administration of GABA at a dose of 100 or 500 mg/kg body weight/day for 3 days significantly improved the markedly elevated levels of blood urea nitrogen and creatinine and the reduced creatinine clearance related to progression of renal failure. Moreover, the rats with acute renal failure exhibited high levels of fractional excretion of sodium (FE_Na) due to alteration of tubule function following injection of glycerol. However, administration of GABA lowered the FE_Na levels dose-dependently. Furthermore, urine osmolarity was markedly reduced in control rats with acute renal failure as compared with normal rats, whereas it was significantly increased by administration of GABA at a dose of 500 mg/kg body weight/day. These results indicate that GABA has potential as a therapeutic agent against the renal damage involved in acute renal failure.     

Effect of aminophylline on cisplatin nephrotoxicity in the rat.

1. The effect of the methylxanthine aminophylline on cisplatin (5 mg kg-1 i.v.)-induced acute renal failure was investigated in the rat. Renal function was measured 5 days after cisplatin administration. 2. Cisplatin caused a polyuric acute renal failure. The creatinine clearance was significantly reduced. 3. Aminophylline (24 mg kg-1 12h-1) ameliorated the cisplatin nephrotoxicity when administered during the maintenance phase of acute tubular necrosis. However, it had no effect when only administered prophylactically before the cisplatin application. 4. Enprofylline (20 mg kg-1 4h-1 with dose adjustment), a methylxanthine lacking adenosine receptor antagonism in comparison to aminophylline, had no protective effect on cisplatin nephrotoxicity. 5. Adenosine is a renal vasoconstrictor and decreases glomerular filtration rate. Endogenous adenosine in the kidney is formed by degradation of ATP and is thought to be involved in various forms of acute renal failure. The results suggest that adenosine may be involved in the haemodynamic changes in the kidney induced by cisplatin.     

Effects of chitosan oligosaccharide (COS) on the glycerol-induced acute renal failure in vitro and in vivo.

The purpose of this study was to investigate the effects of chitosanoligosaccharide (COS) on the change of inflammatory response, renal function factor, and renal oxidative stress in glycerol-induced ARF in vitro and in vivo. The molecular weight of COS was approximately below 10 kDa with 90% degree of deacetylation. Renal proximal tubular cells were treated with only COS (0, 0.01, 0.025, 0.05, 0.075 and 0.1%) or COS in the presence of glycerol (4mM). And rats were administered with glycerol (50%, 8 ml/kg) by intramuscular injection for the induction of ARF. For identification the protection effect of COS in the glycerol-induced ARF, rats were administered by COS (0.05 and 0.1%) using P.O. injection. The enzymatic activity of the released RDPase was assayed by the fluorometric method. The level of TNF-alpha in kidney or the culture medium was quantified using ELISA kit (R&D Systems, Minneapolis, USA) and, nitrite concentration was determined by the Griess reaction. We showed that COS stimulated the production of TNF-alpha, NO and the released RDPase. Glycerol increased the concentration of RDPase in kidney and decreased the released RDPase in proximal tubular cells. And, glycerol increased the production of NO, TNF-alpha, creatinine, and MDA, and decreased SOD. However, COS recovered the glycerol-induced inflammatory response, renal function factor, and antioxidant effect in kidney. COS had the antioxidant activity and the anti-inflammatory effect. And maybe that characteristics could help recover the glycerol-induced ARF.     

Role of tissue repair in survival from s-(1,2-dichlorovinyl)-L-cysteine-induced acute renal tubular necrosis in the mouse.

S-(1,2-Dichlorovinyl)-L-cysteine (DCVC), a model nephrotoxicant in mice, causes acute tubular necrosis and death at high doses. Our earlier studies revealed that renal tissue repair was critical for survival in mice with DCVC nephrotoxicity. The objective of this study was to investigate if increasing renal tissue repair could protect mice from the lethal outcome of DCVC. Male Swiss Webster (SW) mice were administered a low dose of DCVC (15 mg/kg, ip) 72 h before injection of a normally lethal dose of DCVC (75 mg/kg, ip); this resulted in 100% protection against the lethal effect of DCVC. Because DCVC caused approximately two fold decrease in cytosolic and mitochondrial beta-lyase activity, the possibility that DCVC protection may be caused by decreased bioactivation was examined. Mercuric chloride (HgCl2, 6 mg/kg), a nephrotoxicant with no effect on beta-lyase activity, was administered 96 h before a lethal dose of DCVC. This also resulted in 100% protection from the lethal effect of DCVC. In both studies total glutathione was unchanged at any time after the lethal dose of DCVC was administered, obviating the role of glutathione in protection. In both cases the augmented and sustained tissue repair induced by priming dose and documented by 3H-thymidine pulse labeling and immunocytochemistry for proliferating cell nuclear antigen resulted in 100% survival in spite of the extensive renal injury. These findings suggest that stimulation of renal tubular repair by the priming dose, through augmented cell division, and the resistance of new cells to mechanisms of progression of injury, underlies auto- and heteroprotection against DCVC. The molecular mechanisms may have potential application in pharmacotherapeutic intervention for treatment of acute renal failure.