西酞普兰对慢性应激大鼠额叶皮质神经细胞bax mRNA、bcl-2 mRNA表达及凋亡的影响

目的:探讨西酞普兰对慢性应激大鼠的额叶皮质神经细胞bax、bcl-2 mRNA表达的影响。方法:取24只雄性SD大鼠随机分为对照组(不进行任何处理)、应激组(应激+生理盐水灌胃)、实验组(应激+西酞普兰灌胃),采用强迫游泳制造慢性应激模型(15 min/d,共4周),用原位杂交技术检测bax、bcl-2 mRNA表达情况,TUNEL法检测细胞凋亡,尼康图像分析(NIS DR)软件测量各指标阳性细胞数量。结果:应激组较对照组,大鼠额叶皮质bax mRNA阳性表达细胞明显增多(P0.01)、染色加深;bcl-2 mRNA阳性表达细胞明显减少(P0.01)且染色变浅,且TUNEL阳性细胞数量增多(P0.01),染色增强。而实验组较应激组大鼠,额叶皮质bax mRNA阳性表达细胞减少(P0.01)、染色变浅,bcl-2 mRNA阳性表达细胞明显增多(P0.05),染色加深,且TUNEL阳性细胞数量减少(P0.01),染色减弱。结论:大鼠额叶皮质神经细胞bax mRNA和bcl-2 mRNA的表达水平受到慢性应激的影响,导致细胞凋亡加剧,西酞普兰能够有效调控额叶皮质神经细胞bax和bcl-2 mRNA的表达水平,拮抗细胞凋亡,这可能是西酞普兰防治慢性应激引起的神经精神疾病的相关机制之一。     

白藜芦醇甙对慢性酒精中毒大鼠前额叶皮质cdk5表达的影响

目的:研究白藜芦醇甙对慢性酒精中毒大鼠学习记忆及前额叶皮质区细胞周期依赖性蛋白激酶5(cdk5)表达的影响。方法:建立大鼠慢性酒精中毒模型,Y-型迷宫测试空间学习与记忆成绩,实时定量PCR分析前额叶皮质组织cdk5 mRNA的表达;免疫组织化学方法检测大鼠前额叶皮质区cdk5表达。结果:学习记忆测试显示模型组大鼠学习记忆成绩比正常组明显下降,白藜芦醇甙各剂量组与模型组相比,学习记忆成绩明显上升;免疫组化结果表明模型组大鼠前额叶皮质区cdk5阳性表达较正常组明显增多,各剂量组与模型组相比,cdk5阳性表达明显减少;实时定量PCR结果表明模型组大鼠前额叶皮质区cdk5 mRNA表达较正常组明显上升,各剂量组与模型组相比,cdk5 mRNA表达明显下降。结论:白藜芦醇甙可能通过对cdk5表达的调节而发挥抗酒精中毒作用。     

电惊厥及电刺激耳大神经抗惊厥时大鼠海马生长抑素的变化

本工作选用电惊厥大鼠为实验性癫痫模型,观察了电刺激耳大神经对大鼠电惊厥发作的影响,结果表明：电刺激耳大神经能抑制电惊厥诱导的大脑皮层痫样放电,并可以明显缓解惊厥症状。应用免疫组织化学和原位杂交方法观察了电惊厥及电刺激耳大神经抗惊厥后海马神经元生长抑素及其mRNA的变化。结果显示：电惊厥时海马CA4区、下托处生长抑素免疫反应明显减弱,生长抑素mRNA表达显著增高;电刺激耳大神经抗惊厥后,CA4区,下托处生长抑素免疫反应明显增强。生长抑素mRNA表达显著下降。提示：电惊厥时海马生长抑素释放增加,生长抑素基因表达增强,生长抑素的合成增加;电刺激耳大神经抗惊厥后海马生长抑素释放减少,生长抑素基因表达下降,生长抑素的合成减少;电刺激耳大神经对电惊厥的抑制作用与其在海马调控生长抑素基因的表达有关。     

白藜芦醇甙对慢性酒精中毒大鼠学习记忆及前额叶皮质NR2B受体表达的影响

目的：研究白藜芦醇甙对慢性酒精中毒大鼠学习记忆及大脑前额叶皮质N-甲基-D-天冬氨酸受体2B亚基（NR2B）表达的影响。方法：建立大鼠慢性酒精中毒模型,Y-型迷宫测试空间学习与记忆成绩,免疫组织化学方法检测前额叶皮质NR2B表达,聚合酶链式反应（PCR）分析前额叶皮质NR2B mRNA的改变。结果：学习记忆测试显示模型组大鼠学习记忆成绩比正常组明显下降（P〈0.01）,各剂量组与模型组相比,学习记忆成绩明显上升（P〈0.05或P〈0.01）;免疫组化结果表明模型组大鼠前额叶皮质区NR2B阳性表达较正常组明显增多,各剂量组与模型组相比,NR2B mRNA阳性表达明显减少;PCR结果表明模型组大鼠前额叶皮质区NR2B mRNA表达较正常组明显上升（P〈0.01）,各剂量组与模型组相比,NR2B mRNA表达明显下降,差异有显著性（P〈0.01）。结论：白藜芦醇甙可能通过对NMDA受体4F53亚基NR2B蛋白表达的调节而发挥抗酒精中毒作用。     

突触素、神经肽Y(NPY)在糖尿病模型大鼠脑组织细胞中的表达研究

对突触素(synaptophysin)、神经肽Y(NPY)在链尿佐菌素诱导的糖尿病模型大鼠额叶皮质和海马组织细胞中的表达进行研究,并利用UTHSCSA Image Tools 3.0进行图象分析,同时对其与学习记忆的关系进行探讨.选取成年Sprague-Dawley雄性大鼠20只,体重200-300g,随机分为两组.实验组用链尿佐菌素诱导产生糖尿病模型,并以血糖测定和尿糖水平测定进行筛选,另一组为空白对照组.继续饲养4周后,各组大鼠先进行Y型迷宫测试其学习记忆能力,然后取出脑组织,制做连续冰冻切片,对大脑额叶皮质和海马组织进行突触素、神经肽Y酶标免疫组织化学染色,观察这些蛋白在糖尿病大鼠和正常大鼠脑中表达的差异.结果发现糖尿病大鼠在Y型迷宫测试中,错误次数明显增多,糖尿病大鼠额叶皮质和海马神经元数目较正常对照组明显减少,神经细胞内突触素和神经肽Y的表达均较正常对照组明显下降.我们的研究显示突触素和神经肽Y在糖尿病大鼠大脑额叶皮质和海马组织内表达的减少可能与糖尿病组神经细胞突触数目及突触的可塑性下降、学习和记忆能力障碍有关.这可能是造成糖尿病性痴呆的一个因素.     

电针对糖尿病大鼠学习记忆障碍及海马NT-3表达的影响

目的观察电针对糖尿病性认知功能障碍大鼠学习记忆的改善作用,及其对海马神经营养因子-3（NT-3）mRNA和免疫反应阳性细胞表达的影响。方法采用2％链脲佐菌素（streptozotocin,STZ）构建糖尿病大鼠模型,将模型大鼠随机分为电针组（EA）、对照组（DM）与正常组（CN）进行比较。电针4周后糖尿病测定血糖水平,并用Morris水迷宫法观察电针对糖尿病大鼠学习记忆的影响,应用RT-PCR和免疫组化方法检测海马NT-3mRNA和免疫反应阳性细胞的表达水平。结果对照组血糖、上台潜伏期高于正常组和电针组（P〈0．01）,对照组NT-3mRNA和免疫反应阳性细胞的表达明显低于正常组和电针组（P〈0．01）;电针组NT-3表达明显高于对照组（P〈0．01）。结论电针能在一定程度上降低血糖,促进海马NT-3mRNA和免疫反应阳性细胞的表达,改善糖尿病认知功能障碍者的学习和认知功能。     

突触素、神经肽Y（NPY）在糖尿病模型大鼠脑组织细胞中的表达研究

对突触素(synaptophysin)、神经肽Y(NPY)在链尿佐菌素诱导的糖尿病模型大鼠额叶皮质和海马组织细胞中的表达进行研究,并利用UTHSCSA Image Tools3．0进行图象分析,同时对其与学习记忆的关系进行探讨。选取成年Sprague—Dawley雄性大鼠20只,体重200—300g,随机分为两组。实验组用链尿佐菌素诱导产生糖尿病模型,并以血糖测定和尿糖水平测定进行筛选,另一组为空白对照组。继续饲养4周后,各组大鼠先进行Y型迷宫测试其学习记忆能力,然后取出脑组织,制做连续冰冻切片,对大脑额叶皮质和海马组织进行突触素、神经肽Y酶标免疫组织化学染色,观察这些蛋白在糖尿病大鼠和正常大鼠脑中表达的差异。结果发现糖尿病大鼠在Y型迷宫测试中,错误次数明显增多,糖尿病大鼠额叶皮质和海马神经元数目较正常对照组明显减少,神经细胞内突触素和神经肽Y的表达均较正常对照组明显下降。我们的研究显示突触素和神经肽Y在糖尿病大鼠大脑额叶皮质和海马组织内表达的减少可能与糖尿病组神经细胞突触数目及突触的可塑性下降、学习和记忆能力障碍有关。这可能是造成糖尿病性痴呆的一个因素。     

慢性间断性低氧大鼠认知功能和脑胆碱能神经元的进行性变化

目的：探讨慢性间断性低氧（CIH）大鼠认知功能的进行性变化及其与脑胆碱能神经元变化的关系。方法：成年雄性SD大鼠40只,随机均分为对照组、慢性间断性低氧1,3,5周组。应用Morris水迷宫检测认知功能的变化;利用HE染色在光镜下计数前额叶皮层和海马坏死神经元数;利用免疫组化方法检测前额叶皮层和海马胆碱乙酰转移酶（ChAT）阳性表达。结果：CIH各组大鼠学习记忆能力呈进行性下降趋势;与对照组比较,CIH5w组出现明显学习记忆功能障碍（P〈0.05）。CIH各组前额叶皮层和海马变性坏死神经元数增多,且随低氧时间延长,上述改变呈慢性进行性加重趋势。CIH各组前额叶皮层和海马ChAT阳性表达逐渐下降;与对照组比较,CIH3w组和CIH5w组前额叶皮层和海马ChAT阳性表达明显减少,差异具有显著性（P〈0.05）。结论：慢性间断性低氧大鼠认知功能进行性下降与前额叶皮层和海马神经元病理性损伤、ChAT表达进行性减少有关。     

早期糖尿病大鼠晶状体和视网膜水通道蛋白4表达的研究

目的观察早期糖尿病大鼠晶状体、视网膜水通道蛋白4(aquaporin 4,AQP-4)表达的变化,探讨糖尿病大鼠眼组织水代谢改变的机制。方法 SD大鼠分为正常对照组和糖尿病组。制作糖尿病大鼠模型,于第4、8周取材,用免疫组化法和计算机图像分析系统半定量分析各组大鼠晶状体、视网膜AQP-4表达的变化。结果正常及糖尿病大鼠AQP-4在晶状体上皮均无表达。AQP-4在视网膜上有表达,正常大鼠主要表达于视网膜视杆视锥层、节细胞层和神经纤维层,糖尿病大鼠从内界膜延伸至视细胞层整个视网膜厚度均可见AQP-4阳性表达,特别是在神经节细胞层毛细血管内皮和神经纤维层阳性表达更明显。糖尿病大鼠视网膜组织AQP-4阳性表达标随周龄的延长而增强。结论糖尿病大鼠视网膜AQP-4的表达较正常组增强,提示水通道蛋白的表达增加是糖尿病早期发生视网膜水肿的机制之一。     

细胞外信号调节激酶1在大鼠胆汁性肝纤维化形成过程中的含量变化

目的:探讨细胞外信号调节激酶1(ERK1)在肝纤维化形成过程中的含量变化.方法:采用胆总管结扎(BDL)方法建立大鼠胆汁性肝纤维化模型,应用免疫组织化学、Western blotting技术及逆转录聚合酶链式反应(RT-PCR)方法,研究ERK1及其mRNA在肝纤维化不同时期肝组织中的分布及含量的动态变化.结果:正常肝组织有少量ERK1分布,随着肝纤维化的发展,ERK1阳性细胞明显增多;正常大鼠肝组织中有ERK1蛋白表达,造模1～4周明显增多,4周时增加了3.9倍:正常大鼠肝组织中亦有ERK1 mRNA表达,于造模2 d开始上调,造模4周表达最多.结论:肝纤维化形成过程中ERK1及其mRNA含量增加,尤以造模4周最明显.     

Diabetes-induced stimulation of the renin-angiotensin system in the rat brain cortex

Cerebrovascular disease is a threat to people with diabetes and hypertension. Diabetes can damage the brain by stimulating the renin-angiotensin system (RAS), leading to neurological deficits and brain strokes. Diabetes-induced components of the RAS, including angiotensin-converting enzyme (ACE), angiotensin-II (Ang-II), and angiotensin type 1 receptor (AT1R), have been linked to various neurological disorders in the brain. In this study, we investigated how diabetes and high blood pressure affected the regulation of these major RAS components in the frontal cortex of the rat brain. We dissected, homogenized, and processed the brain cortex tissues of control, streptozotocin-induced diabetic, spontaneously hypertensive (SHR), and streptozotocin-induced SHR rats for biochemical and Western blot analyses. We found that systolic blood pressure was elevated in SHR rats, but there was no significant difference between SHR and diabetic-SHR rats. In contrast to SHR rats, the heartbeat of diabetic SHR rats was low. Western blot analysis showed that the frontal cortexes of the brain expressed angiotensinogen, AT1R, and MAS receptor. There were no significant differences in angiotensinogen levels across the rat groups. However, the AT1R level was increased in diabetic and hypertensive rats compared to controls, whereas the MAS receptor was downregulated (p < 0.05). These findings suggest that RAS overactivation caused by diabetes may have negative consequences for the brain's cortex, leading to neurodegeneration and cognitive impairment.     

血小板反应素1在STZ诱导大鼠糖尿病性视网膜病变的表达研究

探讨TSP1表达在糖尿病视网膜病变中的作用和机制,为治疗和预防糖尿病视网膜病变提供新的实验和理论依据。用链脲佐菌素(STZ)腹腔注射建立糖尿病模型8周后,采用免疫组织化学、RT-PCR及实时荧光定量PCR法,分析TSP1在早期链尿佐菌素诱导的糖尿病SD大鼠视网膜中的表达。结果显示在早期糖尿病大鼠的视网膜表面血管、神经节细胞层、内外核层中均有明显的TSP1表达,糖尿病视网膜组TSP1 mRNA表达要高于对照组,其中实时荧光定量PCR CT值的结果显示糖尿病组TSP1 mRNA表达量较对照组要高约3．48倍,二组间差别有显著性意义(P<0．01),提示TSP1在视网膜组织中的表达与糖尿病视网膜病变的发生密不可分,TSP1表达的增加可能在糖尿病视网膜病变的发生和发展中起重要作用。     

肾上腺髓质素在糖尿病视网膜细胞高表达的研究

探讨肾上腺髓质素(Adrenomedullin,AM)在糖尿病视网膜病变(Diabeticretinopathy,DR)发病中的作用。Sprague-Dawley雄性大鼠尾静脉注射链脲佐菌素造模,以血糖测定和尿糖水平测定进行筛选,正常对照组尾静脉注射等量枸橼酸钠缓冲液。成模后继续饲养4周,取出眼球视网膜组织,连续冰冻切片,用免疫组织化学SABC法染色观察各组大鼠视网膜RPE细胞AM的表达情况。糖尿病大鼠成模前,两组动物的体重、血糖和尿糖检测结果间无显著性差异(P>0.05)。成模后4周,糖尿病组与正常组大鼠体重、血糖和尿糖数值差异有显著性意义(P<0.01)。AM在正常组大鼠视网膜节细胞层及内核层均有表达,正常组大鼠视网膜AM的光密度值为76.3±5.3,单位面积AM阳性细胞数为(4.5±1.1)×103/mm2。糖尿病大鼠视网膜内RPE细胞肾上腺髓质素表达显著增强,糖尿病大鼠视网膜RPE细胞AM的光密度值为105.7±11.9,单位面积AM阳性细胞数为(17.9±2.3)×103/mm2。两组相比,差异具有显著性(P<0.01)。AM在糖尿病大鼠视网膜RPE细胞表达量增加很可能是DR发生、发展的重要因素。     

Tissue-specific expression of PPAR mRNAs in diabetic rats and divergent effects of cilostazol

Cilostazol and ligands of peroxisome proliferator-activated receptors (PPARs) have been effectively used to alleviate diabetic complications, but the common and tissue-specific expression patterns of PPARs in different tissues in diabetic patients and those treated with cilostazol have not been reported. Here, we aimed to assess the effects of diabetes and cilostazol on mRNA expression of PPARalpha and PPARgamma in the aorta, renal cortex, and retina of diabetic rats treated with cilostazol for 8 weeks. PPARalpha mRNA expression showed uniform downregulation in all these tissues in diabetic rats, and this effect was reversed by cilostazol treatment. Surprisingly, PPARgamma mRNA expression was reduced in the renal cortex and retina, yet increased in the aorta of diabetic rats, although cilostazol still reversed these changes. Interestingly, cilostazol, a well-known phosphodiesterase 3 inhibitor and cAMP elevator, augmented cAMP content only in the aorta, but showed no significant effects in the renal cortex of diabetic rats. In conclusion, mRNA expression of PPARs is tissue-specific in diabetes and may be differently affected by cilostazol, possibly because of its tissue-specific effects on cAMP content.     

Diabetes enhances apoptosis induced by cerebral ischemia

The aim of this study is to explore the mechanism by which diabetes exaggerates cerebral stroke and its outcome. Since ischemia can be related to not only necrosis but apoptosis as well, we compared the development of apoptosis in STZ-diabetic rats and STZ-diabetic rats subjected to occlusion of the middle cerebral artery (MCA). 24-48 hr following MCA occlusion the animals were killed, the brain removed and prepared for evaluation by several indexes of apoptosis: nucleosomal DNA fragmentation, TUNEL staining, activation of caspase-3 and alteration in the expression of Bax and Bcl2. DNA fragmentation was not detected in the cortex of normal and diabetic animals, but was evident following MCA occlusion in diabetic rats. Bax expression was increased in the cortex of normal rats following MCA occlusion and this expression was further increased in the cortex of MCA occluded diabetic rats. Bcl2 expression was not changed in any of the groups. In the hippocampus, DNA fragmentation was not evident in control rats but was observed in diabetic rats. Ischemic injury did not enhance DNA laddering in diabetic animals. The expression of Bax was increased in diabetic rats but was not increased following MCA occlusion. Bcl2 expression was not changed by ischemia in any of the animal models. These data suggest that diabetes may enhance the development of stroke via increased cortical apoptotic activity but this was not additive in the hippocampus following ischemic injury.     

The Effects of Middle Cerebral Artery Occlusion on Central Nervous System Apoptotic Events in Normal and Diabetic Rats

Apoptosis and neural degeneration are characteristics of cerebral ischemia and brain damage. Diabetes is associated with worsening of brain damage following ischemic events. In this study, the authors characterize the influence of focal cerebral ischemia, induced by middle cerebral artery occlusion, on 2 indexes of apoptosis,TUNEL(terminal deoxynucleotidyl transferase–mediated deoxyuridine 5-triphosphate nick end-labeling) staining and caspase- 3 immunohistochemistry. Diabetes was induced in normal rats using streptozotocin and maintained for 5 to 6 weeks. The middle cerebral artery of both normal and diabetic rats was occluded and maintained from 24 or 48 hours. Sham-operated normal and diabetic animals served as controls. Following 24 to 48 hours of occlusion, the animals were sacrificed and the brains were removed, sectioned, and processed for TUNEL staining or caspase-3 immunohistochemistry. Middle cerebral artery occlusion in normal rats was associated with an increase in the number of both TUNEL-positive and caspase-3– positive cells in selected brain regions (hypothalamic preoptic area, piriform cortex, and parietal cortex) when compared to nonoccluded controls. Diabetic rats without occlusion showed significant increases in both TUNEL-positive and caspase-3–positive cells compared to normal controls. Middle cerebral artery occlusion in diabetic rats resulted in increases in TUNEL-positive as well as caspase-3–positive cells in selected regions, above those seen in nonoccluded diabetic rats. Both TUNEL staining and caspase-3 immunohistochemistry revealed that the number of apoptotic cells in diabetic animals tended to be greatest in the preoptic area and parietal cortex. The authors conclude that focal cerebral ischemia is associated with a significant increase in apoptosis in nondiabetic rats, and that diabetes alone or diabetes plus focal ischemia are associated with significant increases in apoptotic cells.     

Albumin catabolism in diabetic rats

The kinetics of albumin catabolism were studied in normal rats and rats with streptozotocin induced diabetes (blood glucose greater than 500 mg%). Whether determined from the clearance of 125I-albumin from plasma or from the whole body, after 10 days of severe, uncontrolled diabetes there was a 30-35% decrease in the catabolic rate for albumin in the diabetic rats compared to normals. There was also about a 35% contraction of the relative extravascular distribution volume for albumin in the diabetic rats, and about a 25% decrease in the total body mass of albumin. However, the concentration of albumin in the circulation was the same in normal and diabetic animals. We conclude that when the rate of albumin synthesis is substantially depressed in diabetes, the rat maintains normal plasma albumin concentration both by decreasing albumin's fractional catabolic rate and by shifting albumin from the extravascular to the vascular compartment.     

Altered expression of NCAM in hippocampus and cortex may underlie memory and learning deficits in rats with streptozotocin-induced diabetes mellitus

Neurological and structural changes are paralleled by cognitive deficits in diabetes mellitus. The present study was designed to evaluate the expression of neural cell adhesion molecules (NCAM) in the hippocampus, cortex and cerebellum and to examine cognitive functions in diabetic rats. Diabetes was induced in male albino rats via intraperitoneal streptozotocin injection. Learning and memory behaviors were investigated using a passive avoidance test and a spatial version of the Morris water maze test. NCAM expression was detected in the hippocampus, cortex and cerebellum by an immunoblotting method. The diabetic rats developed significant impairment in learning and memory behaviours as indicated by deficits in passive avoidance and water maze tests as compared to control rats. Expression of NCAM 180 and 120 kDa were found to be higher in hippocampus and cortex of diabetic rat brains compared to those of control, whereas expression of NCAM 140 kDa decreased in these brain regions. Our findings suggest that streptozotocin-induced diabetes impairs cognitive functions and causes an imbalance in expression of NCAM in those brain regions involved in learning and memory. Altered expression of NCAM in hippocampus may be an important cause of learning and memory deficits that occur in diabetes mellitus.     

Early oxidative stress in the diabetic kidney: effect of DL-alpha-lipoic acid

Oxidative stress is implicated in the pathogenesis of diabetic nephropathy. The attempts to identify early markers of diabetes-induced renal oxidative injury resulted in contradictory findings. We characterized early oxidative stress in renal cortex of diabetic rats, and evaluated whether it can be prevented by the potent antioxidant, DL-alpha-lipoic acid. The experiments were performed on control rats and streptozotocin-diabetic rats treated with/without DL-alpha-lipoic acid (100 mg/kg i.p., for 3 weeks from induction of diabetes). Malondialdehyde plus 4-hydroxyalkenal concentration was increased in diabetic rats vs. controls (p <.01) and this increase was partially prevented by DL-alpha-lipoic acid. F(2) isoprostane concentrations (measured by GCMS) expressed per either mg protein or arachidonic acid content were not different in control and diabetic rats but were decreased several-fold with DL-alpha-lipoic acid treatment. Both GSH and ascorbate (AA) levels were decreased and GSSG/GSH and dehydroascorbate/AA ratios increased in diabetic rats vs. controls (p <.01 for all comparisons), and these changes were completely or partially (AA) prevented by DL-alpha-lipoic acid. Superoxide dismutase, glutathione peroxidase, glutathione reductase, glutathione transferase, and NADH oxidase, but not catalase, were upregulated in diabetic rats vs. controls, and these activities, except glutathione peroxidase, were decreased by DL-alpha-lipoic acid. In conclusion, enhanced oxidative stress is present in rat renal cortex in early diabetes, and is prevented by DL-alpha-lipoic acid.     

Effects of alpha-lipoic acid on biomarkers of oxidative stress in streptozotocin-induced diabetic rats

Increased oxidative stress and impaired antioxidant defense mechanisms are important factors in the pathogenesis and progression of diabetes mellitus and other oxidant-related diseases. This study was designed to determine whether alpha-lipoic acid, which has been shown to have substantial antioxidant properties, when administered (10 mg/kg ip) once daily for 14 days to normal and diabetic female Sprague-Dawley rats would prevent diabetes-induced changes in biomarkers of oxidative stress in liver, kidney and heart. Serum glucose concentrations, aspartate aminotransferase activity, and glycated hemoglobin levels, which were increased in diabetes, were not significantly altered by alpha-lipoic acid treatment. Normal rats treated with a high dose of alpha-lipoic acid (50 mg/kg) survived but diabetic rats on similar treatment died during the course of the experiment. The activity of glutathione peroxidase was increased in livers of normal rats treated with alpha-lipoic acid, but decreased in diabetic rats after alpha-lipoic acid treatment. Hepatic catalase activity was decreased in both normal and diabetic rats after alpha-lipoic acid treatment. Concentrations of reduced glutathione and glutathione disulfide in liver were increased after alpha-lipoic acid treatment of normal rats, but were not altered in diabetics. In kidney, glutathione peroxidase activity was elevated in diabetic rats, and in both normal and diabetic animals after alpha-lipoic acid treatment. Superoxide dismutase activity in heart was decreased in diabetic rats but normalized after treatment with alpha-lipoic acid; other cardiac enzyme activities were not influenced by either diabetes or antioxidant treatment. These results suggest that after 14 days of treatment with an appropriate pharmacological dose, alpha-lipoic acid may reduce oxidative stress in STZ-induced diabetic rats, perhaps by modulating the thiol status of the cells.