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.     

Efficacy of melatonin as protectant against oxidative stress and structural changes in liver tissue in pinealectomized rats

Previous observations demonstrated that physiological levels of melatonin, the pineal secretory product, are important in protecting against oxidative stress-induced tissue damage. We investigated the effects of pinealectomy and administration of exogenous melatonin on liver tissue in rats. Pinealectomized (Px) and sham-operated (non-Px) rats were used. We evaluated structural changes, reduced glutathione (GSH) levels and malondialdehyde (MDA) levels. Rats were divided into three groups (10 rats in each group): control (non-Px), Px+vehicle and Px+melatonin (4 mg/kg given daily intraperitoneally for 10 days). Liver GSH levels were significantly lower in Px rats than in the control group. Melatonin administration significantly increased GSH levels (p < 0.05). Px caused a significant increase in MDA levels as compared with the control group and melatonin administration to Px rats significantly reduced MDA levels in the liver (p < 0.05). Sinusoidal dilatation to a varying degree developed in all Px rats. Severity of mononuclear cell infiltration and sinusoidal congestion were lower in Px+melatonin group than in the Px group. These findings suggest that a significant increase in oxidative and structural changes occur in rat livers after pinealectomy, which can be diminished by melatonin treatment.     

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.     

Activation of group I metabotropic glutamate receptors depresses recurrent inhibition of motoneurons in the neonatal rat spinal cord in vitro

A variety of experimental studies have demonstrated the neuroprotective effects of melatonin, based on its antioxidant activity. In a prospective randomized study, the effects of melatonin were investigated in experimental head trauma-induced oxidative stress in rabbits. The experimental study was performed on 30 rabbits. The animals were divided into three groups. Group I (sham procedure): a right parietal craniotomy was performed on each animal, and the dura mater was left intact. Group II: experimental brain trauma (EBT) was performed on each animal using a 1 cm inner diameter × 10 cm long glass tube, through which a 20 g weight (0.5 cm diameter) was dropped onto the brain at the craniotomy site, causing a contusional head trauma. Group III: the same EBT model was performed, but 2.5 mg/kg melatonin was injected intraperitoneally four times (total dose 10 mg/kg); these injections were performed 20 min before the operation, during the trauma, 1 h later and 2 h later. The rabbits were sacrificed after the EBT at 24 h after the brain trauma. The activities of the three principal antioxidant enzymes—catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px)—were determined, and the levels of malondialdehyde (MDA), a product of lipid peroxidation, and glutathione (GSH) were measured in brain homogenates. MDA levels were found to be higher in the EBT group than in the EBT+melatonin group or the sham procedure group. The SOD activity was found to be higher in the EBT group than in the sham procedure group. Enzymatic parameters (except for SOD) were significantly higher in melatonin-treated animals than in EBT animals. GSH levels in melatonin-treated animals were decreased compared with EBT animals. In conclusion, the data indicate that melatonin protects against free radical-mediated oxidative changes in brain tissue by boosting antioxidant enzymes, and in particular lowering lipid peroxidation in rabbits with EBT.     

The antioxidant melatonin reduces cortical neuronal death after intrastriatal injection of kainate in the rat

 The anti-excitotoxic efficacy of the pineal hormone melatonin was investigated in kainate-injured brains of rats. Kainate (a glutamate-receptor agonist, 2.5 nmol in 1 μl) was directly injected to unilateral striatum. Melatonin (10 mg/kg) was administrated intraperitoneally 1 h before and 1, 3, and 5 h after intrastriatal kainate injection in adult Sprague-Dawley rats. Three days after kainate injection, a significant neuronal damage was found, as determined by Nissl staining and the TUNEL method, not only in the injected striatum, but also in the ipsilateral neighboring cortex. The kainate-induced cortical apoptotic neuronal death was significantly attenuated by treatment with melatonin compared with the vehicle control group. However, no detectable changes were observed in the contralateral side of the brain in either vehicle- or melatonin-treated rats. Moreover, the biochemical results indicated that kainate can indeed induce oxidative stress, such as a decrease in the content of total glutathione (GSH), oxidized glutathione (GSSG), and an increase in the ratio of GSSG/GSH in the striatum and cortex compared with the contralateral brain regions. In the kainate-injected striatum, melatonin did not reduce the oxidative stress, but in the neighborhood of injected area-cortex, kainate-induced oxidative stress was significantly reduced by melatonin. Enhancement of glutathione-peroxidase activity was induced by intrastriatal kainate injection, not only in the cortical area of control and melatonin-treated rats, but also in striatum of control rats. However, a large elevation was found in the melatonin-treated cortex. Taking the morphological and biochemical data together, the present results suggest that melatonin functions as an antioxidant by upregulating the glutathione antioxidative defense system, thereby reducing neuronal death caused by excitotoxicity and preventing the kainate-induced damage from spreading to adjacent brain regions. Received: 16 December 1997 / Accepted: 30 July 1998     

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.     

3-硝基酪氨酸在细菌内毒素诱导大鼠血管低反应性中的介导作用

目的：观察3-硝基酪氨酸（3-NT）对感染性休克大鼠血管低反应性的介导作用及抗氧化剂对此的治疗效果。 方法： 40只雄性SD大鼠随机分成空白对照组(n=10); LPS休克组（LPS 15 mg·kg-1 iv, n=10）; 尿酸(UA)治疗组（注射LPS 1 h后200 mg·kg-1 ip, n=10）; N-乙酰-5-甲氧基色胺（melatonin）治疗组（注射LPS 1 h后10 mg·kg-1 ip, n=10）。空白对照组及注射LPS 6 h后各组动物，静注去氧肾上腺素（PE, 0.5-2.5 μg·kg-1）,记录注药后MAP的增加百分比。所有in vivo实验结束后取大鼠胸主动脉环作张力实验,，建立PE的剂量-反应曲线并计算相应的Emax、EC50值。注射LPS 6 h后检测各组动物血浆丙二醛（MDA）、硝酸盐/亚硝酸盐（nitrate/nitrite）与3-NT的含量。 结果： 静脉注射PE后，休克组动物MAP的平均增长率与对照组相比显著降低至54.60%（P<0.01）；而UA组、melatonin组MAP对PE反应的增长率较之休克组分别增高了37.70%、40.03%(P<0.05)。休克组大鼠胸主动脉环对PE的反应［(Emax，35.30%±9.80%； EC50， (15.70±4.50)nmol/L］与对照组相比有显著差异［（Emax，100%； EC50， (4.71±2.04) nmol/L, P<0.05］，经UA、melatonin治疗后血管反应性有显著改善(P<0.05)。尿酸、N-乙酰-5-甲氧基色胺治疗组的血浆MDA、硝酸盐/亚硝酸盐和3-NT的浓度也明显低于休克组(P<0.05)。 结论： 3-NT是感染性休克血管低反应的重要介导因子，抗氧化剂通过清除氧自由基，减少脂质过氧化物的形成、抑制体内NO的过量合成及有效清除3-NT，从而改善α-肾上腺素能受体介导的血管低反应性，对临床感染性休克病人的治疗可能有积极作用。     

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.     

Effect of ornithine on the ileal histology,nitric oxide production and lipid peroxidation in LPS-induced endotoxemia

Effect of ornithine which is known to inhibit L-arginine uptake via cationic amino acid transport system has been tested, and compared to aminoguanidine, an iNOS inhibitor in lypopolysaccharide (LPS)-induced endotoxemia in rats. Serum nitrite/nitrate and malondialdehyde (MDA) level have been measured, and ileal histology has also been examined. Endotoxin increased serum nitrite/nitrate and MDA levels from 15.7+/- 2.4 micromol/ml and 2.1 +/-0.2 nmol/ml to 23.1 +/- 1.0 micromol/ml and 5.2+/- 0.3 nmol/ml (both P<0.05), respectively. In addition, LPS caused ileal degeneration. L-ornithine (500 mg/kg) did not improve septic manifestations, i.e., serum nitrite/nitrate and MDA levels did not differ from those in endotoxemia. Neither does it have an improving action on ileal histology. However, higher dose of L-ornithine (2,500 mg/kg) lowered the increased level of nitrite/nitrate and MDA by LPS. Moreover, it restored ileal histology from grade 3 (median) to 0 (median) (P<0.05). On the other hand, aminoguanidine (100 mg/kg) normalized serum nitrite/nitrate and MDA levels but not ileal histology in endotoxemic rats. In conclusion, high dose of L-ornithine could improve endotoxemic parameters in LPS-treated rats.     

Effect of melatonin on the thymus, adrenal glands, and spleen in rats during acute stress

We studied the effects of acute stress and exogenous melatonin on stress marker organs in rats. Administration of melatonin under normal conditions increased the relative weights of the thymus (active rats) and adrenal glands (active and passive rats). The relative weight of the spleen also tended to increase after melatonin treatment. Stress led to involution of the thymus and hypertrophy of the adrenal glands in active and especially in passive animals receiving physiological saline. Melatonin partially or completely prevented involution of the thymus under stress conditions. Stress had no effect on the relative weight of the adrenal glands in melatonin-treated rats. The relative weight of the spleen in active rats receiving melatonin in doses of 0.5 and 1 mg/kg decreased after stress exposure. Our results suggest that melatonin modulates the hemodynamics and function of stress marker organs. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 141, No. 3, pp. 263–266, March, 2006     

The effect of melatonin on liver superoxide dismutase activity, serum nitrate and thyroid hormone levels

Melatonin is a main neurohormone of the pineal gland. The effects of melatonin on the level of serum thyroid-stimulating hormone (TSH), thyroxine (T(4)), triiodothyronine (T(3)), nitrate, melatonin and liver superoxide dismutase (SOD) activity were examined in rats. Melatonin was injected at the dose of 10 mg/kg for 7 days, 2 h before turning the lights off. Rats were decapitated at 10:00 a.m. and 02:00 a.m., which are the times of the lowest and highest serum melatonin levels, respectively. Blood and tissue samples were collected. Decreased TSH, T(3), T(4) and nitrate levels were determined in the melatonin-injected and nighttime groups. Melatonin levels showed a diurnal rhythm. SOD activity increased in the melatonin-treated group. The results demonstrate that increased SOD activity, and reduced serum TSH, T(3), T(4) and nitrate levels correlated with the serum melatonin levels.     

小檗碱增强表柔比星诱导T24细胞G_0/G_1期阻滞的作用机制

目的:探讨小檗碱联合表柔比星对膀胱癌T24细胞周期的影响及相关作用机制。方法:实验将膀胱癌T24细胞分为4组:对照组、表柔比星组、表柔比星+小檗碱组和小檗碱组,采用MTT法检测细胞的活力,检测药物处理后对膀胱癌T24细胞增殖的抑制情况。用流式细胞术分析T24细胞周期分布并用Western blot法测定cyclin D1、CDK2、CDK4、P21和P27蛋白的表达水平。结果:小檗碱联合表柔比星显著抑制T24细胞的活力,存在时间依赖性,联合用药组的G_0/G_1期细胞比例增高,S期和G_2期细胞比例降低,与单用药物组及对照组比较有显著性差异(P0.05)。联合用药上调细胞周期依赖性激酶抑制蛋白P27和P21蛋白的表达水平,同时下调cyclin D1、CDK2及CDK4细胞周期蛋白的表达水平。结论:小檗碱增强表柔比星对膀胱癌T24细胞增殖的抑制及G_0/G_1期阻滞,其作用机制可能与上调P27及P21蛋白和抑制cyclin D1、CDK2及CDK4蛋白表达有关。     

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.     

Effects of melatonin on streptozotocin-induced diabetic liver injury in rats

This study investigated the possible protective effects of melatonin as an antioxidant against streptozotocin (STZ)-induced diabetic liver injury in rats. Wistar rats were divided into four groups: untreated control (UC), melatonin-treated control (MC), untreated diabetic (UD), and melatonin-treated diabetic (MD). Experimental diabetes was induced by a single-dose (60 mg/kg, intraperitoneally (ip)) STZ injection, and melatonin was injected (200 microg/kg/day, ip) for 4 weeks. Upon light and electron microscopic examination, we observed that melatonin improved the morphological and histopathological changes of the liver caused by diabetes. Malondialdehyde levels in the liver homogenates of UD rats were higher than those of controls and were markedly reduced after melatonin treatment. Although no significant difference was observed with respect to antioxidant status, the superoxide dismutase activity tended to be higher in the UD rats than in the treated rats. Our findings showed that melatonin administration partially reduced liver injury in STZ-induced diabetic rats.     

黄酒多酚减轻阿霉素心脏毒性的初步研究

目的:探讨黄酒多酚化合物(YWPC)减轻阿霉素(即多柔比星,DOX)所致心脏毒性的作用及其机制。方法:将40只雄性SD大鼠随机分成4组:对照组、YWPC组、DOX组和DOX+YWPC组。干预4周后,超声心动图检测大鼠心功能;病理学染色观察心脏组织病理学改变;比色法、DHE染色、TUNEL染色和Western blot法检测心肌组织中心肌酶、氧化应激和凋亡水平的改变。结果:与对照组相比,DOX组左室射血分数(LVEF)和左室短轴缩短分数(LVFS)明显下降,而收缩期左室内径(LVIDs)和舒张期左室内径(LVIDd)明显增加;而与DOX组相比,DOX+YWPC组LVEF和LVFS增加,LVIDs和LVIDd下降(P 0. 05)。DOX组血清心肌损伤指标乳酸脱氢酶(LDH)、肌酸激酶(CK)、天冬氨酸转氨酶(AST)和心肌肌钙蛋白I(c Tn I)较对照组明显增加;而DOX+YWPC组上述指标较DOX组下降(P 0. 05)。与对照组比较,YWPC组无明显病理学改变,DOX组出现心肌纤维排列紊乱、细胞核溶解和肌纤维解体,而DOX+YWPC组上述情况明显改善。与对照组比较,DOX组活性氧簇(ROS)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和谷胱甘肽(GSH)水平下降,丙二醛(MDA)水平增加;与DOX组相比,DOX+YWPC组上述指标均得到逆转(P 0. 05)。同时,DOX组较对照组心肌细胞凋亡水平、Bax/Bcl-2比和cleaved caspase-3水平增加,而DOX+YWPC组心肌细胞凋亡明显受到抑制(P 0. 05)。结论:黄酒多酚可以通过减少氧化应激和抑制心肌细胞凋亡拮抗阿霉素所致的心脏毒性。     

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.     

Chronic treatment with melatonin attenuates serotonergic degeneration in the striatum and olfactory tubercle of zitter mutant rats

The effects of chronic treatment with the antioxidant hormone melatonin on degeneration of serotonergic fibers were studied in the striatum and olfactory tubercle of the zitter rat, which shows a loss-of-function mutation of the glycosylated transmembrane protein attractin. In these animals, serotonergic fibers in the striatum and olfactory tubercle undergo spontaneous and progressive degeneration as a result of abnormal metabolism of reactive oxygen species. Homozygous zitter (zi/zi) rats were provided ad libitum access to drinking water containing melatonin for 9 months (M) after weaning. High-performance liquid chromatography analysis revealed that melatonin treatment significantly increased serotonin in the caudate-putamen, (CPU), nucleus accumbens (NA) and olfactory tubercle (OT). Immunohistochemical staining for serotonin was consistent with the neurochemical data and further demonstrated substantially increased numbers of serotonergic nerve terminals in these areas. Aberrant serotonergic fibers characterized by swollen varicosities (>1 microm in diameter) were observed in the CPU and NA of 10 M zi/zi rats. The number of these fibers decreased after melatonin treatment ended. Furthermore, hyperinnervation of serotonergic fibers was observed in the OT of melatonin-treated zi/zi rats. These results suggest that melatonin protects serotonergic fibers and terminals in zitter rats and/or promotes their neuroplasticity.     

Experimental depression induces renal oxidative stress in rats

Depression has been associated to inflammatory and oxidative events. Previous report has shown renal oxidative stress in patients with depression. In order to analyze if depressive status is related to renal oxidative and inflammatory events, Sprague Dawley rats were submitted to forced swimming test (FST) and the renal oxidative metabolism, monocyte-macrophage infiltration and Angiotensin II (Ang II) expression were determined. Rats were submitted to FST daily (30 min) for 15 days. Motor activity was analyzed before FST. Kidney sections were homogenized to measure nitric oxide (NO), malondialdehyde (MDA), reduced glutathione (GSH) and catalase activity by enzymatic and biochemical methods. Renal frozen sections were studied for superoxide anion (O₂-), monocyte/macrophage infiltration and Ang II expression by histochemical and immunofluorescence methods. In addition, three groups of FST rats were treated with losartan, sertraline or water for 18 days with further renal O₂-analysis. In the FST group, struggle time, motor activity, food intake and body weight gain were found decreased. Increased number of glomerular, interstitial and tubular O₂-positive cells was observed in FST rats. High renal content of nitrite/nitrate (NO), MDA and decreased amount of GSH were found in FST rats. Values of renal ED-1 or Ang II positive cells in FST rats remained similar to controls; however, AT1 receptor blocking (losartan) and sertraline reduced both depressive-like behavior and renal O₂-expression. These data suggests that depression-like behavior in rats is involved in kidney oxidative stress probably mediated by AT1 receptors.     

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。     

Effect of Cannabis sativa on oxidative stress and organ damage after systemic endotoxin administration in mice

The effect of Cannabis sativa extract on oxidative stress and organ tissue damage during systemic inflammation was studied. For this purpose, Swiss mice were challenged with a single intraperitoneal dose of lipopolysaccharide (LPS; 200 μg/kg) to mimic aspects of mild systemic infection. Cannabis resin extract (5, 10, or 20 mg/kg) (expressed as Δ⁹-tetrahydrocannabinol) was given via subcutaneous route for 2 days prior to and at the time of endotoxin administration. Mice were euthanized 4 h after LPS injection. Malondialdehyde (MDA), reduced glutathione (GSH), and nitric oxide (nitrite/nitrate) in the brain, liver, kidney, lung, and heart as well as brain glucose were measured. Alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) were measured in liver homogenates. Histopathological examination of different organs was performed, and immunohistochemical techniques were used to evaluate expression levels of inducible nitric oxide synthase (iNOS) and caspase-3 in the brain and liver. The administration of only cannabis (20 mg/kg) decreased MDA, increased GSH, and decreased glucose level in the brain. No significant effects were observed for cannabis alone on MDA, GSH, or nitric oxide in other organs or on liver enzymes. The administration of LPS increased MDA and nitric oxide, while GSH decreased in different organs. Brain glucose increased by endotoxin. AST, ALT, and ALP were markedly increased in the liver tissue. In LPS-treated mice, cannabis (20 mg/kg) decreased MDA. GSH increased in the brain, kidney, and lung, nitric oxide decreased in the brain and lung while brain glucose decreased after the highest dose of cannabis. Cannabis failed to alter the level of liver enzymes. Histological damage in the brain, kidney, heart, lung, and liver due to endotoxin is increased by cannabis. Increased immunoreactivity of caspase-3 in the cytoplasm of the hepatocytes was observed after LPS and cannabis cotreatment compared with the LPS only group. Caspase-3 immunoreactivity markedly increased in degenerating neurons of the cortex following cannabis and LPS cotreatment. iNOS inmmunoreactivity increased after LPS and more intense iNOS expression was detected in hepatocytes after cannabis and LPS cotreatment. iNOS expression increased after cannabis and LPS treatment especially in the cerebral cortex. Thus, the administration of cannabis decreased tissue oxidative stress but increased organ damage after endotoxin injection in mice.