Effects of pinealectomy and exogenous melatonin on rat hearts

The effects of pinealectomy and administration of melatonin, the major secretory product of the pineal gland, which is a direct free radical scavenger and an indirect antioxidant, were studied in rat hearts on the basis of cardiac morphology and biochemical findings. Three groups of Wistar rats were used: one group was the sham-operated control, one group consisted of pinealectomized rats and one group consisted of pinealectomized rats that were treated with melatonin. Serum cholesterol, tissue levels of malondialdehyde (MDA) and reduced glutathione (GSH), and heart weight were determined. Histochemical staining with the Van Gieson, PAS/Alcian blue at pH 2.5 and Masson's trichrome methods were performed in addition to hematoxylin-eosin staining. Levels of serum cholesterol and tissue MDA, and heart weight were increased in pinealectomized rats whereas GSH levels did not change. Melatonin administration reversed these effects. Microscopically, myocardial fibrosis and myxomatous degeneration of cardiac valves were detected in all pinealectomized rats. It can be concluded that pinealectomy of rats causes morphological changes in rat hearts, and short-term application of melatonin does not reverse these changes.     

Effects of vitamin E supplementation on oxidative stress in streptozotocin induced diabetic rats: investigation of liver and plasma

This experimental study was designed to investigate the effects of vitamin E supplementation, especially on lipid peroxidation and antioxidant status elements 3/4 namely, glutathione (GSH), CuZn superoxide dismutase (CuZn SOD), and glutathione peroxidase (GSH Px), both in blood and liver tissues of streptozotocin (STZ) diabetic rats. The extent to which blood can be used to reflect the oxidative stress of the liver is also investigated. In diabetic rats, plasma lipid peroxide values were not significantly different,from control,whereas erythrocyte CuZn SOD (p < 0.01), GSH Px (p < 0.001) activities and plasma vitamin E levels (p < 0.001), were significantly more elevated than controls. Vitamin E supplementation caused significant decreases of erythrocyte GSH level (p < 0.01) in control rats and of erythrocyte GSH Px activity (p < 0.05) in diabetic rats. Liver findings revealed significantly higher lipid peroxide (p < 0.001) and vitamin E (p < 0.01) levels and lower GSH (p < 0.001), CuZn SOD (p < 0.001) and GSH Px (p < 0.01) levels in diabetic rats. A decreased hepatic lipid peroxide level (p < 0.01) and increased vitamin E/lipid peroxide ratio (p < 0.001) were observed in vitamin E supplemented, diabetic rats. A vitamin E supplementation level which did not cause any increase in the concentration of the vitamin in the liver or blood, was sufficient to lower lipid peroxidation in the liver. Vitamin E/lipid peroxide ratio is suggested as an appropriate index to evaluate the efficiency of vitamin E activity,independent of tissue lipid values. Further, the antioxidant components GSH, GSH Px and CuZn SOD and the relationships among them, were affected differently in the liver and blood by diabetes or vitamin E supplementation.     

Melatonin protects against epirubicin-induced cardiotoxicity

We investigated the cytoprotective effect of melatonin in epirubicin-induced cardiotoxicity using four experimental groups of male Wistar rats: untreated control rats, epirubicin-treated rats, epirubicin+melatonin-treated rats, and melatonin-treated rats. We examined the histopathological and biochemical effects of melatonin on the epirubicin-induced changes and measured the levels of the lipid peroxidation end-product (malondialdehyde, MDA), an indicator of nitric oxide (NO) synthesis (nitrite/nitrate production), and reduced glutathione (GSH) in the heart. We also studied the extracellular matrix components (fibronectin, laminin) in the heart. Vacuole formation, mitochondrial deformation and degeneration, and disordered myofibrillary structures were detected ultrastructurally in the epirubicin-treated group. The degeneration was reduced in the heart tissues of the epirubicin+melatonin group. Epirubicin increased the nitrite/nitrate production, but did not change the MDA and GSH levels significantly. Melatonin treatment lowered the nitrite/nitrate concentrations, while increasing the GSH levels, which exceeded the levels in epirubicin+melatonin-treated rats. We conclude that the epirubicin increased the nitrozative stress, not the oxidative stress, in heart tissue, and the cardioprotective effect of melatonin was partially attributed to the suppression of epirubicin-induced nitrozative stress. These results suggest that melatonin partially protects against epirubicin-induced cardiotoxicity.     

松果体及褪黑素对大鼠胸腺CD4+/CD8+T细胞分化发育的影响

目的：探讨松果体和褪黑素对胸腺T细胞分化发育的影响。方法：实验组为松果体摘除组和松果体摘除 褪黑素组。ABC法染胸腺CD4^ 、CD8^ 细胞。流式细胞术测定胸腺和血液T淋巴细胞CD4^ 、CD8^ T亚类。结果：松果体摘除后胸腺明显萎缩,并随时间延长而加剧,补充褪黑素后胸腺重量逐渐恢复。松果体摘除后胸腺和血液中CD4^ T细胞百分比无明显波动;胸腺CD8^ T细胞比例上升,但血液CD8^ T细胞比例则下降;补充褪黑素后胸腺CD4^ T细胞在低剂量组略有下降,而高剂量组则显著升高,胸腺和血液CD8^ T呈下降趋势,双阳性细胞比例恢复正常,双阴性细胞比例则上升。结论：松果体能显著影响CD8^ T细胞的分化发育和释放,降低血液CD8^ T细胞的比例。补充褪黑素能缓解相关影响。     

Protective effects of pentoxifylline on acute liver injury induced by thioacetamide in rats

Pentoxifylline (PTX) is a non-selective phosphodiesterase inhibitor with the effects of antioxidation, anti-inflammation and anti-fibrosis that has been shown to induce damage in liver. The purpose of this study is to investigate the effects and possible mechanisms of PTX on thioacetamide (TAA)-induced acute liver injury in rats. Male Sprague-Dawley (SD) rats were divided into four groups: control, PTX, TAA and PTX+TAA treated groups. Rats were administrated TAA together with or without PTX for a week and sacrificed 24 h after the last intragastric administration of PTX. Histopathological analysis was carried out. The liver function, the indices of oxidative stress including malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione (GSH) in liver tissues, and pro-inflammatory cytokines expressions were examined. The mRNA level of NF-κB p65 in liver was also determined. PTX significantly attenuated TAA-induced liver injury. The serum transaminase and MDA levels were reduced while the levels of SOD and GSH were increased, as compared with the TAA-treated group. PTX also remarkably suppressed the secretions of pro-inflammatory cytokines and the nuclear factor-κB (NF-κB) activation induced by TAA. In addition, the histopathological analysis showed that the range and degree of liver tissue lesions were improved obviously in PTX treated group. Pentoxifylline could ameliorate the effects of thioacetamide-induced acute liver injury in rats by inhibiting oxidative stress, expressions of pro-inflammatory cytokines and NF-κB activation.     

Protective effects of melatonin against spinal cord injury induced oxidative damage in rat kidney: A morphological and biochemical study

Spinal cord injury (SCI) induced oxidative stress affects multiple organ systems including the kidney. We studied the possible protective effects of melatonin on SCI-induced oxidative damage in renal tissues of rats. Wistar albino rats (n = 24) were exposed to SCI and divided into vehicle- or melatonin-treated SCI groups. Melatonin was administred intraperitoneally at a dose of 10 mg/kg for seven days. Renal tissues were investigated by light and electron microscopy. Furthermore, tissue malondialdehyde (MDA) and glutathione (GSH) levels and myeloperoxidase (MPO) and superoxide dismutase (SOD) activities were also determined. In the vehicle-treated SCI group, the renal histology was disturbed compared to controls, whereas the melatonin-treated SCI group showed significantly reduced degeneration of renal tissue as seen by both light and electron microscopy. MDA levels, MPO and SOD activities were increased and GSH levels were decreased in the vehicle-treated SCI group compared to controls. On the other hand, decreased MDA levels and MPO activities and increased GSH levels were observed in the melatonin-treated SCI group compared to vehicle-treated SCI group. These results showed that experimentally induced SCI caused oxidative stress in the rat kidney, whereas melatonin treatment reduced oxidative stress, suggesting that it may be used as a complementary therapy of renal problems occurring following SCI.     

Effects of melatonin on Leydig cells in pinealectomized rat: an immunohistochemical study

We have investigated immunohistochemically the effects of melatonin on Leydig cells in rat. Three groups of Wistar rats were used. Rats in group I and II were sham-pinealectomized (control) and pinealectomized, respectively, whereas rats in group III were pinealectomized and injected daily with melatonin for 2 months. At the end of the experiment, all animals were killed by decapitation and blood samples were obtained. Serum testosterone levels were determined with the use of a chemiluminescent enzyme immunoassay. Testicular tissue was collected and processed for semiquantitative evaluation of immunohistochemical testosterone staining. Intensity of immunostaining was determined on a scale between 0 (no staining) and 5 (heavy staining). In pinealectomized rats, serum testosterone levels were significantly increased as compared to sham-pinealectomized rats. Daily administration of melatonin after pinealectomy resulted in significant decreased serum testosterone levels as compared to levels in control and pinealectomized rats. Immunostaining of testosterone was moderate (3+) in sham-pinealectomized rats, heavy (5+) in pinealectomized rats and low (1+) in pinealectomized rats that were treated with melatonin, respectively. The results of our study indicate that pinealectomy induces increased testosterone secretion in Leydig cells and this increased secretion can be prevented by administration of melatonin.     

Effects of melatonin on lipid peroxidation and antioxidative enzyme activities in the liver,kidneys and brain of rats administered with benzo(a)pyrene

Benzo(a)pyrene [B(a)P] is a widespread pollutant with a mutagenic, carcinogenic and strong prooxidative properties. The present study evaluated the melatonin effects on lipid peroxidation products levels and on activity of antioxidative enzymes in the course of B(a)P intoxication. Control rats were treated with 0.9% NaCl; another group was given 10 mg melatonin/kg bw; a third group was injected twice a week with B(a)P at the dose of 10 mg/kg bw; the fourth group received both B(a)P and melatonin at the dose as mentioned above. The experiment continued for 3 months. In homogenates of brain, liver and kidneys lipid peroxidation was appraised by evaluation of malonyldialdehyde and 4-hydroxyalkenal (MDA+4HDA) levels. Activities of glutathione peroxidase (GPx), superoxide dysmutase (SOD) and catalase (CAT) and concentration of reduced glutathione (GSH) were also estimated. In animals receiving both B(a)P and melatonin, lower levels of MDA+4HDA were observed in all organs as compared to the group treated with B(a)P only. Following administration of B(a)P, GSH level decreased in brain and kidney. Melatonin in combination with B(a)P induced rises in the GSH level in liver and brain, as compared to the receiving B(a)P alone. The activity of SOD increased in the rats treated with melatonin alone but the highest activity was observed in rats treated with B(a)P plus melatonin. CAT activity in the melatonin-treated group increased in brain and liver. Similar to SOD, activity of the enzyme significantly increased in the group treated in combination with B(a)P and melatonin, as compared to the remaining groups in all tested tissues. The results suggest that melatonin protects cells from the damaging action of B(a)P. According to our knowledge, there are no studies describing the effects of melatonin on lipid peroxidation markers and antioxidative enzymes during intoxication of B(a)P in the brain, liver and kidneys. The results of present study give a perspective for further studies of its free radical scavenger properties in prevention of oxidative stress dependent diseases, among others cancers caused by carcinogens such as B(a)P.     

Misoprostol decreases oxidative stress and liver injury in bacterial lipopolysaccharide-induced endotoxemia in mice

The effect of misoprostol, a synthetic prostaglandin E1 analog, on the development of oxidative stress induced in mice with lipopolysaccharide (LPS) endotoxin was investigated. Misoprostol was administered by intraperitoneal route (i.p.) at doses of 10, 100, or 1,000 μg/kg at the time of LPS injection (200 μg/kg, i.p.). Mice were euthanized 4 h later. Lipid peroxidation (malondialdehyde; MDA), reduced glutathione (GSH), nitric oxide (nitrite/nitrate) levels as well as paraoxonase activity were measured in brain and liver. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities as well as DNA fragmentation were determined in the liver. The administration of LPS increased oxidative stress both in the brain and liver tissue. There were significantly increased MDA and nitrite and decreased GSH and PON1 activity in the brain and liver, respectively. In addition, LPS was associated with markedly elevated plasma ALT and AST level as well as increased liver DNA fragmentation. The administration of misoprostol at 100 or 1,000 μg/kg decreased brain MDA by 17.6 and 30 %, increased GSH by 29.8 and 33.3 %, and decreased nitric oxide by 21.74 and 42.5 %, respectively, compared with the lipopolysaccharide control group. Liver MDA decreased by 27 %, GSH increased by 47.7 %, and nitric oxide decreased by 37.2 % with misoprostol at 1,000 μg/kg. Paraoxonase activity increased in both the brain and liver by misoprostol administration. The increase in liver AST and ALT and DNA fragmentation after endotoxin administration was normalized by misoprostol. These results indicate that misoprostol can alleviate oxidative stress in the presence of a mild systemic inflammatory illness, indicating a new and potentially important therapeutic application for the drug.     

The Expression of Inflammatory Cytokines on the Aorta Endothelia Are Up-regulated in Pinealectomized Rats

This study was designed to investigate the effect of melatonin on the expression of aortic inflammatory cytokines and its underlying mechanisms in rats. Melatonin deficiency rats (Px, N?=?16) were created by pinealectomy and were fed with normal diet for 16 weeks after the surgery, and compared with sham-operated rats (Con, N?=?14). Serum lipid profile, glucose metabolism parameters, serum oxidative stress and inflammatory biomarkers were evaluated. The expression of inflammatory cytokines in the aorta endothelia was analyzed. To evaluate the signal transduction pathways of melatonin on the expression of cytokines, rat aortic endothelial cell lines (RAECs) were treated with melatonin, and their protein expressions of inflammatory cytokines and phosphorylation levels of relevant signal pathways were detected. At the 16th week after surgery in Px rats, their serum triglyceride, very low density lipoprotein cholesterol, free fatty acid and glucose levels were prominently elevated (all P?<?0.05); serum oxidative stress biomarker malondialdehyde, serum inflammatory biomarkers oxidized low-density lipoprotein, tumor necrosis factor-α, interleukin-6 and C reactive protein were also significantly increased. Meanwhile, the expression of inflammatory cytokines: monocyte chemotactic protein-1 (MCP-1), vascular adhesion molecule 1 (VCAM-1) and matrix metalloproteinase-9 (MMP-9) of the aorta endothelia in Px rats were significantly up-regulated (all P?<?0.05). In vitro, melatonin significantly decreased the expression of MCP-1, VCAM-1 and MMP-9 proteins, along with the suppression of phosphorylation levels of nuclear factor κB (NF-κB)/P65 and p38 mitogen-activated protein kinase (P38-MAPK) in RAECs. Melatonin deficiency elevates the serum inflammatory biomarkers and increases aortic inflammatory responses. Melatonin regulates these inflammatory responses by NF-κB and P38-MAPK involved pathways.     

松果体及褪黑素对大鼠胸腺巨噬细胞酪氨酸激酶受体B表达的影响

目的:研究松果体摘除及补充褪黑素对大鼠胸腺巨噬细胞酪氨酸激酶受体B(trkB)表达的影响.方法:选用2月龄清洁级SD大鼠,分为正常对照组、假手术对照组、松果体摘除组、松果体摘除+褪黑素注射7.5mg·kg~(-1)·d~(-1)组和松果体摘除+褪黑素腹腔15mg·kg~(-1)·d~(-1)组,术后4、 8周取材.应用trkB和单克隆抗体ED1免疫荧光双标显色法观察分析松果体摘除及补充外源性褪黑素后胸腺巨噬细胞trkB表达的变化.结果:与对照组相比,松果体摘除术后4周胸腺双阳性细胞表达减弱,补充褪黑素后无变化.术后8周松果体摘除组与对照组相比无明显差异,而低剂量组双阳性细胞表达异常增高,高剂量组恢复正常.各组平均灰度无明显差异.结论:松果体及褪黑素在影响胸腺细胞分化发育过程中,胸腺巨噬细胞表达的trkB也随之发生变化,其与胸腺细胞表达的trkB共同作用参与胸腺细胞分化发育.胸腺神经内分泌微环境的分泌调节是松果体及褪黑素保护胸腺细胞的通路之一.     

Not Only Melatonin but also Caffeic Acid Phenethyl Ester Protects Kidneys against Aging-related Oxidative Damage in Sprague Dawley Rats

Microscopic features and antioxidant status of kidneys of young, old, and caffeic acid phenethyl ester (CAPE) and melatonin administered old Sprague Dawley rats were evaluated. Aging-related tubular and glomerular changes were evident. The most prominent tubular alterations were massive vacuole formation, mitochondrial degeneration, and lysosome accumulation. Mean tissue malondialdehyde (MDA) level was increased, mean tissue superoxide dismutase (SOD), catalase (CAT) (p < .001), and glutathione peroxidase (GPx) activities (p < .05), and total glutathione (GSH) level were decreased in old animals. Melatonin significantly reduced tissue MDA levels (p < .005), but increased tissue SOD (p < .001), CAT, and GPx activities (p < .05), and GSH levels (p < .005) in old animals. CAPE also significantly reduced tissue MDA levels (p < .005), but increased tissue SOD (p < .05), CAT (p < .005), GPx activities, and GSH levels (p < .001) in old rats. Mean tissue MDA levels of melatonin and CAPE-administered rats were even lower than those of young rats (p < .05). In conclusion, tubular and glomerular structures and tissue antioxidant enzyme activities were very well preserved in CAPE and melatonin-administered rats.     

The effect of pentoxifylline on ultrastructure and antioxidant potential during cyclophosphamide-induced liver injury

The aim of this study was to evaluate the effect of pentoxifylline (PTXF) (30 mg/kg b.w. for 10 days) on the antioxidant potential in the rat liver after single intraperitoneal (i.p.) cyclophosphamide (CP) administration (150 mg/kg b.w.) and to draw a correlation between the morphological changes and biochemical findings. Morphological examinations were based on ultrastructural analysis in the transmission electron microscope. It was found that single i.p. CP administration caused destructive changes, particularly within mitochondria and in the smooth endoplasmic reticulum of hepatocytes. The changes were accompanied by an increase in the MDA (malondialdehyde) level in liver tissue homogenates. The animals receiving PTXF + CP showed no normalization of MDA level, the same damage of the liver as those given CP, and marked statistically significant decrease in the activity of GSH/Px (glutathione peroxidase) compared to CP-receiving animals. No statistically significant differences were revealed in the activity of Cu,Zn-SOD and GSSR (superoxidase dismutase, glutathione reductase) both between control animals and CP- or CP + PTXF-receiving groups, or between CP and CP + PTXF groups.     

褪黑激素对老年大鼠肝MDA含量和GSH—px、CAT，Ca^2＋—ATPase活性的影响

为探讨褪黑激素保肝抗衰老的作用及其机理 ,文章观察了褪黑激素对老年大鼠肝过氧化脂质产物含量和氧自由基、细胞内钙离子清除能力的影响。连续 30天给初老大鼠补充褪黑激素后 ,用生化比色法测定了肝组织内丙二醛 (MDA)含量和谷胱甘肽过氧化物酶 (GSH- px) )、氢过氧化物酶(CAT)、钙离子 -三磷酸腺苷酶 (Ca2 - ATPase)活性。与对照组比较 ,实验组大鼠肝内 MDA含量下降了 31.2 % ,GSH- px、CAT和 Ca2 - ATPase活性分别提高了 2 5.1%、49.6%和 2 5.4%。提示 ,褪黑激素能增强肝细胞抗氧化能力和清除细胞内游离钙离子的能力 ,具有一定的保护肝细胞和抗衰老作用。     

Protective and Therapeutic Effect of Molsidomine on Bleomycin-Induced Lung Fibrosis in Rats

We aimed to investigate the preventive and treatment effect of molsidomine (MOL) on bleomycin (BLC)-induced lung injury in rats. Rats were assigned into groups as follows: control group; MOL group, 10 mg/kg MOL was continued orally for 29 day; BLC group, a single intratracheal injection of BLC (2.5 mg/kg), MOL+BLC-preventive group, 10 mg/kg MOL was administered 1 day before the intratracheal BLC injection and continued for 14 days; BLC+MOL-treatment group 10 mg/kg MOL was given on 14th day after the intratracheal BLC injection and continued until sacrifice. All animals were sacrificed on 29th day after BLC administration. The semiquantitative histopathological assessment, tissue levels of malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), reduced glutathione (GSH), total antioxidant status (TAS), total oxidant status (TOS), myeloperoxidase (MPO), and oxidative stress index (OSI) were measured. BLC-provoked histological changes were significantly detected compared to the control group. MOL restored these histological damages in different quantity in the treatment and preventive groups. BLC administration significantly decreased levels of GSH and TAS when compared to controls and these reductions was significantly ameliorated by MOL given prophylactic setting. However, therapeutic MOL administration significantly increased the TAS level decreased by BLC. The levels of MDA, MPO, and TOS were significantly increased with BLM, and these augmentations of MDA and TOS were significantly reduced by MOL given prophylactic setting. Furthermore, the OSI was higher in the BLC group, and this increase was reversed by the MOL administration before and after BLC treatment. In this study, both protective and therapeutic effects of MOL against BLC-induced lung fibrosis were demonstrated for the first time.     

胆维他片对肝纤维化大鼠肝中抗氧化体系的影响

目的 探讨胆维他片对肝纤维化大鼠肝中抗氧化体系的影响。方法 选取30只大鼠按照随机数字表法分为肝纤维化模型组、胆维他片组和正常对照组,每组10只。除正常对照组外,其余各组均要求制备大鼠肝纤维化模型。正常对照组和肝纤维化模型组不给药,胆维他片组于造模开始给予灌胃给药,其余组给予蒸馏水灌胃,于第12周测定肝中丙二醛（MDA）、抗氧化体系的过氧化氢酶（CAT）、超氧化物歧化酶（SOD）、谷胱甘肽（GSH）,同时采用Masson's染色肝组织胶原行纤维半定量评估纤维化的程度。结果 纤维化模型组和胆维他片组CAT、SOD、GSH低于正常对照组,MDA高于正常对照组,差异有统计学意义（P＜0.05）;胆维他片组CAT、SOD、GSH均高于纤维化模型组,MDA低于纤维化模型组,差异有统计学意义（P＜0.05）。纤维化模型组和胆维他片组肝纤维化分期高于正常对照组,差异有统计学意义（P＜0.05）;胆维他片组肝纤维化分期低于纤维化模型组,差异有统计学意义（P＜0.05）。结论 胆维他片能有效降低肝纤维化肝内的脂质过氧化,促进肝内氧化及抗氧化体系的恢复,具有减轻肝纤维化的作用。     

松果体褪黑素对大鼠胸腺CD4~+ CD25~+调节性T细胞发育及其相关基因Foxp3的影响

目的研究松果体摘除及补充褪黑素对大鼠胸腺CD4+ CD25+调节性T细胞(Treg细胞)产生、输出及其相关基因叉状头/翅膀状螺旋转录子(Foxp3)表达的影响。方法选用雄性清洁级SD大鼠120只,分为正常组、假手术组、松果体摘除组、松果体摘除+褪黑素低剂量组[腹腔注射7.5mg/(kg·d)]和松果体摘除+褪黑素高剂量组[腹腔注射15mg/(kg·d)],术后4、8周取材。应用流式细胞检测技术、RT-PCR法及免疫组织化学染色法观察并分析松果体摘除及补充外源性褪黑素后胸腺及外周血CD4、CD25双阳性细胞数量及胸腺Foxp3表达的变化。结果松果体摘除术后无论4周或者8周胸腺CD4+ CD25+ Treg细胞数量均无明显变化,补充褪黑素后双阳性细胞数量呈时间、剂量依赖性明显增加;松果体摘除术后4周外周血CD4+ CD25+ Treg细胞数量明显增加,但补充褪黑素后恢复正常,而术后8周各组之间无显著性差异;半定量RT-PCR及免疫组织化学结果显示,松果体摘除后4周大鼠胸腺Foxp3表达水平明显升高,补充高低两种剂量褪黑素后均有所下降并达到正常水平,而松果体摘除后8周各组之间Foxp3的表达无明显差异。结论松果体摘除对胸腺CD4+ CD25+ Treg细胞的产生无明显影响,但导致大鼠胸腺Foxp3的转录和翻译明显增加,胸腺CD4+ CD25+ Treg细胞的输出增加,而补充外源性褪黑素后能逆转上述异常,长时间作用则其影响逐渐消失。     

miR-195抑制剂降低1型糖尿病小鼠肝脏氧化应激损伤

目的探究miR-195对1型糖尿病C57BL/6小鼠肝脏的Sirt1及其下游氧化应激和线粒体凋亡相关蛋白表达的影响。方法将小鼠分为对照组(Control组)、糖尿病组(DM组)、miR-195抑制剂组(DM+antago组)。按常规法复制DM组模型,miR-195抑制剂(2.5 mg/kg)转染DM+antago组小鼠。DM组及对照组只注射scrambled shRNA(2.5 mg/kg)作为对照。每周观察记录小鼠的体质量和血糖的增减情况。取新鲜的肝脏组织,一部分处理后制片并HE染色进行组织病理学观察;另一部分用于测定肝脏组织中MDA含量及T-SOD活力,并通过RT-qPCR和Western blot检测3组小鼠肝组织中相关指标的mRNA及蛋白含量。结果1)与对照组相比,DM组肝脏组织的小叶都表现出结构紊乱,肝细胞明显水肿,胞质疏松;与糖尿病组相比,DM+antago组肝细胞水肿情况有所减轻。2)与对照组相比,DM组miR-195mRNA的表达,MDA含量及AcFoxo1/Foxo1蛋白表达均明显升高(P<0.05),而Sirt1、Foxo1 mRNA及蛋白表达,T-SOD活力均显著下降(P<0.05);与DM组相比,DM+antago组miR-195mRNA的表达,MDA含量及AcFoxo1/Foxo1蛋白表达明显下降(P<0.05),而Sirt1、Foxo1 mRNA及蛋白表达,T-SOD活力均明显升高(P<0.05)。结论miR-195在1型糖尿病大鼠肝脏氧化应激中表达增加,Sirt1可能是miR-195的作用靶点。     

Melatonin attenuates renal ischemia-reperfusion injury in nitric oxide synthase inhibited rats

Recent studies show that melatonin reduces the blood pressure (BP) and ischemia/reperfusion (I/R)-induced damage. This study was designed to investigate the effects of melatonin on the renal I/R injury in rats given the nitric oxide synthase (NOS) inhibitor, N(omega)-nitro-L-arginine methyl ester (L-NAME). After right nephrectomy, I/R was induced by occlusion of the left renal vessels for 60 min, followed by 24h reperfusion. The administration of melatonin significantly attenuated BP in NOS-inhibited hypertensive rats. Malondialdehyde (MDA) levels, a stable metabolite of the free-radical-mediated lipid peroxidation cascade, were found to be significantly higher in the I/R group (3.48+/-0.2mg/l serum) than in the control group (2.69+/-0.2mg/l serum). L-NAME (40 mgkg(-1) for 15 days)+I/R significantly increased the MDA levels compared to I/R alone. Melatonin administration to L-NAME rats significantly reduced the MDA values resulting from I/R. We also demonstrated that I/R, and especially L-NAME+I/R, lead to structural changes in the kidney and that melatonin attenuates these changes. These results suggest that melatonin reduces BP and I/R injury in NOS inhibited rats by L-NAME.     

Resveratrol reduces light and electron microscopic changes in acetaminophen-induced hepatotoxicity in rats: Role of iNOS expression

Introduction: Hepatotoxicity is a major complication of acetaminophen (APAP), a widely used analgesic and antipyretic drug. Resveratrol (RSV) is a naturally occurring diphenol and it has anticancer, antioxidant, and anti-inflammatory properties. Objectives: In this study, the beneficial effects of RSV on APAP-induced hepatotoxicity was investigated in rats. Materials and methods: Group 1: Ethanol, Group 2: Saline, Group 3: RSV (10 mg/kg/ip), Group 4: APAP (1000 mg/kg/ip/single dose), Group 5: APAP+RSV (20 min after administration of APAP). The rats were sacrificed 24 h after administration of APAP. Light and electron microscopic changes were evaluated. Levels of malondialdehyde (MDA) and glutathione (GSH), catalase (CAT), and superoxide dismutase (SOD) activities were determined in liver tissue. Results: Rats of the ethanol, saline, and RSV groups did not present any histopathological alterations. In the APAP group, we observed vascular congestion, necrosis, inflammation, sinusoidal dilatation, and loss of glycogen content. In the APAP+RSV group, these changes were markedly reduced. iNOS immunostaining showed very weak positive stained hepatocytes the sections of control, saline, and RSV groups. However, in the APAP group, iNOS immunostaining was most evident in pericentral hepatocytes. In the same areas in APAP+RSV group, intensity of iNOS immunostaining decreased. A significant increase in MDA and decreases in GSH level, CAT, and SOD activity indicated that APAP-induced hepatotoxicity was mediated through oxidative stress. Significant beneficial changes were noted in tissue oxidative stress indicators in rats treated with RSV. Conclusion: These biochemical, histopathological, and ultrastructural findings revealed that RSV reduced the severity of APAP-induced alterations in liver.