Prevention of doxorubicin-induced experimental cardiotoxicity by Nigella sativa in rats

IntroductionDoxorubicin (DOX) is an anthracycline cytotoxic chemotherapeutic drug that is commonly used in cancer treatment. A major side effect limiting the clinical use of DOX is cardiotoxicity due to oxidative injury. Nigella sativa (NS) is an annual flowering plant with antioxidant properties. Its seeds contain several bioactive constituents such as saturated and unsaturated fatty acids, thymoquinone, dithymoquinone, thymohydroquinone, and thymol. In this study, we investigated the effect of NS extract on DOX-induced cardiotoxicity.MethodsThe experimental study animals consisted of 28 male Sprague Dawley rats weighing between 300 and 400 g. Four study groups each of seven rats were defined: controls; NS extract; DOX; and DOX+NS. Control and DOX rats received standard food, while each rat in the NS and DOX+NS groups also received 100 mg/kg NS extract orally. At day 28 of follow-up, rats in the DOX groups were administered a single 10 mg/kg intraperitoneal dose of DOX, while rats in the control and NS groups received a single 10 mg/kg dose of physiological saline solution. All animals were monitored for 35 days. On day 35, the rats were decapitated and serum and cardiac tissue samples were obtained. Troponin and NT-proBNP levels were measured in blood sera, while malondialdehyde (MDA), nitric oxide, total antioxidant capacity (TAC), and total oxidative stress (TOS) levels were quantified in sera and tissue samples. Histological alterations that were assessed in cardiac tissue included myocyte disarray, small vessel disease, myocyte hypertrophy, and fibrosis.ResultsThe DOX group had significantly higher NT-proBNP, TOS, and MDA, with greater histopathological derangement. TAC was significantly elevated in the DOX+NS group, which also exhibited significantly lower troponin, TOS, and MDA, as well as significantly higher TAC compared to the DOX group. Histopathological examination showed that the significant structural derangement observed in DOX rats was markedly and significantly reduced in DOX+NS rats.ConclusionOur results suggest that NS extract may prevent DOX-induced cardiotoxicity and thus represents a promising cardioprotective agent.     

鲁斯可皂苷元通过抑制p38MAPK途径及心肌细胞焦亡改善小鼠阿霉素心肌病

目的 观察和探索鲁斯可皂苷元(Rus)对小鼠阿霉素(DOX)心肌病的影响及可能机制,旨在为临床上DOX心脏毒性的预防和治疗提供参考依据.方法 通过单次腹腔注射DOX(15mg/kg)的方式构建急性DOX心肌病小鼠模型,采用随机数表法将32只雄性C57BL/6小鼠(8～10周)随机分为空白对照组(Sham组)、Rus组、...     

The protective effect of melatonin on adriamycin-induced acute cardiac injury

BACKGROUND: Cardiotoxicity is the main complication of adriamycin (ADR), which is a widely used chemotherapeutic agent. OBJECTIVE: To examine the potential cardioprotective effect of melatonin (MEL) on acute ADR cardiotoxicity in a rat model. METHODS: Cardioprotection was assessed on the basis of myocardial lipid peroxidation and ultrastructure. Rats were given MEL at a daily dose of 5 mg/kg and ADR 15 mg/kg, intraperitoneally. The MEL-1 group rats received one dose and the MEL-7 group rats six daily doses of MEL and were sacrificed at the end of one and seven days, respectively. Rats in the ADR-1 and ADR-7 groups were each given a single dose of ADR, and were then sacrificed 24 h and seven days later, respectively. The MEL+ADR-1 group rats received one dose each of ADR and MEL simultaneously and were sacrificed 24 h later. The MEL+ADR-7 group received a single dose of ADR plus a daily MEL dose for six consecutive days, and were sacrificed seven days after the ADR injection. RESULTS: Lipid peroxidation products were elevated in both ADR-1 and ADR-7 groups, and this elevation was significantly inhibited by MEL treatment. Electron microscopy confirmed that ADR was positively cardiotoxic after one and seven days of exposure. The extent of ADR-induced myocardial damage was markedly reduced when MEL was combined with ADR (MEL+ADR-1 and MEL+ADR-7). CONCLUSION: The results suggest that MEL is highly efficacious at reducing the acute cardiotoxic effects of high dose ADR, and that it acts by preventing lipid peroxidation.     

The Cardioprotective Effects of an Antiemetic Drug, Tropisetron, on Cardiomyopathy Related to Doxorubicin

Cardiotoxicity is a life-threatening side effect of doxorubicin (DOX). Although the responsible mechanisms are largely unknown, it is demonstrated that DOX induces an elevation in the level of creatine kinase isoenzyme, lactic dehydrogenase, creatine phosphokinase, and troponin T in serum and reduces body/heart weight. In addition, cardiotoxicity is further confirmed by changes in ECG parameters and papillary muscle contractile force. Tropisetron is an effective antiemetic drug for chemotherapy-induced emesis. There is ample evidence that tropisetron exerts immune modulatory and anti-inflammatory properties. The present study was designed to investigate the protective effects of tropisetron pretreatment against DOX-induced cardiotoxicity in rats. In this study, DOX toxicity was induced by a single intraperitoneal injection (15?mg/kg), and in treated group, tropisetron (3?mg/kg; i.p) was administered 1?h prior to DOX injection. Our results indicated that tropisetron potently decreased body/heart weight loss and mortality rate and also improved ECG changes as well as heart contractility. In addition, tropisetron robustly counteracted the increase in the levels of serum biomarkers and alleviated the histopathological changes in rats?? hearts as compared with the DOX group. Taken together, these results demonstrate that tropisetron has potent cardioprotective effects against DOX-induced cardiotoxicity.     

A Chemosensitizer Drug: Disulfiram Prevents Doxorubicin-Induced Cardiac Dysfunction and Oxidative Stress in Rats

In the present study, the preventive effects of orally administered disulfiram (DS) against the doxorubicin (DOX)-induced cardiotoxicity were investigated in rats. DS was orally administered for 7 days at doses of 2, 10, and 50 mg/kg/day. DOX (30 mg/kg) was intraperitoneally administered on the 5th day of the initiation of DS treatment. Within 48 h of injection, DOX treatment significantly altered ECG, elevated the ST height, and increased the QT and QRS intervals. It reduced the cardiac levels of injury markers like creatine kinase isoenzyme-MB and lactate dehydrogenase. DOX elevated the serum levels of SGOT and nitric oxide. Its injection significantly induced lipid peroxidation in the cardiac tissue and reduced the activities of innate antioxidants like super oxide dismutase, catalase, and reduced glutathione in the cardiac tissue. DOX treatment raised the TNF-α level and caused histological alterations in the myocardium like neutrophil infiltrations, myonecrosis, and edema. Pre-treatment of rats with DS (2, 10, and 50 mg/kg p. o. for 7 days) prevented the ECG changes, minimized oxidative stress, and normalized the biochemical indicators of the DOX-induced cardiotoxicity. DS also protected rat heart from DOX-induced histological alterations. Recently, DS is reported to exert chemosensitization of cancer cells. Our in vitro investigation using MCF7 cell line revealed that DS reverses the DOX-induced suppression of NF-κB and Nrf2 expression. These findings about the protective activity of DS against the DOX-induced cardiotoxicity warrant a detailed investigation on its utility as an adjunct therapy to cancer chemotherapy.     

Efficacy of 1400 W,a novel inhibitor of inducible nitric oxide synthase,in preventing interleukin-1beta-induced suppression of pancreatic islet function in vitro and multiple low-dose streptozotocin-induced diabetes in vivo

OBJECTIVE: Nitric oxide (NO), generated by inducible nitric oxide synthase (iNOS), has been implicated in beta-cell destruction in type 1 diabetes. In the present study, we tested a highly selective iNOS inhibitor, 1400 W, against interleukin-1beta (IL-1beta) induced suppression of rat pancreatic islets, and investigated whether 1400 W could prevent multiple low-dose streptozotocin (MLDS) induced diabetes in mice. Furthermore, we studied if 1400 W affected lipopolysaccharide (LPS) induced increase in plasma nitrite+nitrate (NO(x)) in mice. DESIGN AND METHODS: Precultured rat pancreatic islets were exposed for 48 h to 0, 1, 10 or 50 micromol/l 1400 W in the presence or absence of 25 U/ml IL-1beta, whereupon islet functions were analyzed. MLDS-treated mice were given 5.9 mg/kg body weight of 1400 W intraperitoneally daily or 14 mg/kg body weight twice a day. Blood glucose was monitored and degree of pancreatic mononuclear infiltration was determined. Mice previously injected intraperitoneally with LPS (500 microg) were given 1400 W (14 mg/kg body weight) intraperitoneally and plasma NO(x) was determined after 3, 6 and 10 h. RESULTS: The inhibitor alone did not affect islet functions. 1400 W (50 micromol/l) fully counteracted both the suppression of glucose oxidation rate, (pro)insulin biosynthesis and nitrite accumulation caused by IL-1beta. Cytokine-induced decrease in medium insulin accumulation and glucose-stimulated insulin release was partly counteracted by 1400 W, suggesting that inhibition of insulin release was partially NO independent. LPS-induced increase in plasma NO(x) was markedly inhibited for up to 10 h after 1400 W administration. Irrespective of 1400 W treatment, animals treated with MLDS developed hyperglycemia and pancreatic insulitis. CONCLUSIONS: 1400 W counteracted IL-1beta-induced suppression of rat islets in vitro and LPS induction of NO(x) in vivo, however, it failed to protect against MLDS diabetes in vivo. The latter might be due to a failure by 1400 W in vivo to inhibit NO formation at the level of the pancreatic islet.     

Combined Effects of Quercetin and Atenolol in Reducing Isoproterenol-Induced Cardiotoxicity in Rats: Possible Mediation Through Scavenging Free Radicals

In this investigation, combined effects of quercetin and atenolol in the regulation of isoproterenol (ISO)-induced cardiotoxicity have been evaluated in rats. While ISO administration increased the levels of serum creatine kinase-MB (CK-MB), lactate dehydrogenase (LDH) and glutamate pyruvate transaminase (SGPT) as well as cardiac malondialdehyde (MDA); it reduced the activities of superoxide dismutase, catalase, glutathione peroxidase and the level of reduced glutathione. ISO-induced rats also exhibited ST-segment elevation and tachycardia. Oral administration of atenolol (6?mg/kg) and quercetin (5?mg/kg), along with ISO (5?mg/kg, subcutaneously) every day for 10?days markedly reduced the serum CK-MB, LDH and SGPT levels. Concomitantly the test drugs improved the status of antioxidative enzymes, decreased the cardiac MDA and nearly normalized the electrocardiogram. Electron paramagnetic resonance study also revealed a decrease in 5,5'-dimethyl-1-pyroline-N-oxide-hydroxyl radicals signal intensity when atenolol and quercetin were administered together to ISO-treated rats. In conclusion, the combined treatment of atenolol and quercetin appears to produce a better cardioprotective effect in ISO-induced animals as compared to their individual treatments, and possibly the beneficial actions are associated with the free radical scavenging action of quercetin.     

Role of exogenous melatonin in reducing the nephrotoxic effect of daunorubicin and doxorubicin in the rat

The aim of these studies was to examine the nephroprotective effect of melatonin following the anthracycline administration [daunorubicin (DNR); doxorubicin (DOX)] in rats. Application of these drugs in chemotherapy is limited because of their cardiotoxicity and nephrotoxicity. Rats of the Buffalo strain were divided into groups according to the cytostatic drug used, its dose and sequence of administration [DNR or DOX single (i.v.) dose of 10 mg/kg b.w., i.e. acute intoxication and 3 mg/kg b.w. (i.v.) weekly for 3 wk, subchronic intoxication]. Melatonin was administered subcutaneously before and after every injection of a cytostatic drug at a dose of 10 mg/kg b.w. The severity of renal alterations was examined both biochemically [levels of lipid peroxidation markers, malonyldialdehyde (MDA) and 4-hydroxyalkenals (4-HDA)], or histologically. A statistically significant decrease in renal damage was noted after melatonin administration to acutely or subchronically intoxicated DNR-treated and DOX-treated rats. Biochemical assays revealed significant decreases in MDA and 4-HDA levels following application of melatonin during subchronic DNR or DOX intoxication. In summary, melatonin was found to exert a protective effect on the kidney, which was particularly evident after subchronic DOX and DNR intoxication, using both histological or biochemical methods.     

Melatonin stimulates the activity of protective antioxidative enzymes in myocardial cells of rats in the course of doxorubicin intoxication

The study aimed at determining the effect of melatonin on the activity of protective antioxidative enzymes in the heart and of lipid peroxidation products in the course of intoxication with doxorubicin (DOX). The rats were categorized into four groups, receiving: 0.9% NaCl i.p. (NaCl control); melatonin [20 mg/kg body weight (b.w.)] s.c. (control Mel); DOX (2.5 mg/kg b.w.) i.p.; melatonin plus DOX in doses as above. All the substances were administered once in a week for four consecutive weeks. Homogenates of heart tissue were examined for activities of glutathione peroxidase (GPx), superoxide dismutase (SOD), catalase (CAT), levels of reduced glutathione (GSH) and of lipid peroxidation indices (MDA + 4-HDA). Administration of melatonin alone did not induce alterations in levels of MDA + 4-HDA, GSH, or in activity of GPx, SOD or CAT, as compared to the group receiving 0.9% NaCl. GSH levels decreased following DOX but remained at normal levels following DOX and melatonin. The level of MDA + 4-HDA increased following DOX, as compared with the control, a change prevented by the combination of DOX + melatonin. Activities of GPx, SOD and CAT were higher in groups receiving DOX and/or DOX plus melatonin than in control groups. Activity of CAT and the level of GSH in the group receiving DOX plus melatonin were significantly higher than in the group intoxicated with DOX alone. The obtained results demonstrate that, when given in parallel with DOX, melatonin protects cardiomyocytes from damaging effects of the cytostatic drug (reflected by the levels of MDA + 4-HDA). The protective effect resulted, in part from the augmented levels of GSH and from stimulation of CAT activity by melatonin in cardiomyocytes subjected to the action of DOX.     

Dietary omega-3 supplementation exacerbates left ventricular dysfunction in an ovine model of anthracycline-induced cardiotoxicity

BackgroundCumulative dose-dependent nonischemic cardiomyopathy (NICM) remains a significant risk with the use of some chemotherapeutic agents. In this context, omega-3 polyunsaturated fatty acids (PUFA) have been investigated for their cardioprotective potential in rodent and in vitro models of anthracycline toxicity, with conflicting results. This study evaluated prophylactic omega-3 PUFA supplementation in a large-animal model of anthracycline-induced NICM.Methods and ResultsMerino sheep were randomized to oral drenching with omega-3 PUFA (fish oil; n = 8) or olive oil placebo (n = 9) 3 weeks before commencing repeated intracoronary infusions of doxorubicin (DOX) to induce cardiac dysfunction. Cumulative DOX dose was 3.6 mg/kg. Drenching was continued for 12 weeks after final DOX exposure. Despite significant increases in tissue omega-3 PUFA levels (P < .05 vs placebo), omega-3–treated sheep displayed greater signs of anthracycline cardiotoxicity than placebo animals, consisting of left ventricular dilatation and a greater decline in ejection fraction (P < .05), although myocardial fibrosis burden was similar in both groups.ConclusionsDietary intake of omega-3 PUFA fails to prevent and may indeed exacerbate DOX-induced cardiotoxicity. Clinical use of omega-3 supplementation during chemotherapy should be deferred until more information is available regarding the mechanisms of interaction between fatty acids and the myocardium during anthracycline exposure.     

Enhanced Cardioprotection Against Ischemia-Reperfusion Injury with Combining Sildenafil with Low-Dose Atorvastatin

Summary Purpose: Both ATV and SL reduce myocardial infarct size (IS) by enhancing expression and activity of NOS isoforms. We investigated whether atorvastatin (ATV) and sildenafil (SL) have synergistic effects on myocardial infarct size (IS) reduction and enhancing nitric oxide synthase (NOS) expression. Method: Rats were randomized to nine groups: ATV-1 (1 mg/kg/d); ATV-10 (10 mg/kg/d); SL-0.7 (0.7 mg/kg); SL-1 (1 mg/kg); ATV-1 + SL-0.7; water alone (controls); 1400W (iNOS inhibitor; 1 mg/kg); ATV-10 + 1400W; and ATV-1 + SL-0.7 + 1400W. ATV was administered orally for 3 days. SL was administered intraperitoneally 18 h before surgery and 1400W intravenously 15 min before surgery. Rats either underwent 30 min ischemia-4 h reperfusion or the hearts were explanted for immunoblotting and enzyme activity tests without being exposed to ischemia. Results: IS (% risk area, mean ± SEM) was smaller in the ATV-10 (13 ± 1%), SL-1 (11 ± 2%), SL-0.7 (18 ± 2%) and ATV-1 + SL-0.7 (9 ± 1%) groups as compared with controls (34 ± 3%; P < 0.001), whereas ATV-1 had no effect (29 ± 2%). ATV-1 + SL-0.7 (9 ± 1%) reduced IS more than SL-0.7 alone (p = 0.012). 1400W abrogated the protective effect of ATV-10 (35 ± 3%) and ATV-1 + SL-0.7 (34 ± 1%). SL-0.7 and ATV-10 increased phosphorylated endothelial (P-eNOS; 210 ± 2.5% and 220 ± 8%) and inducible (iNOS; 151 ± 1% and 154 ± 1%) NOS expression, whereas ATV-1 did not. These changes were significantly enhanced by ATV-1 + SL-0.7 (P-eNOS, 256 ± 2%, iNOS 195 ± 1%). SL-1 increased P-eNOS (311 ± 22%) and iNOS (185 ± 1%) concentrations. Conclusions: Combining low-dose ATV with SL augments the IS limiting effects through enhanced P-eNOS and iNOS expression.     

Angiotensin II type 1a receptor mediates doxorubicin-induced cardiomyopathy.

Although the serious cardiotoxicity of doxorubicin (DOX), a useful chemotherapeutic agent, limits the use of this agent, the mechanism of DOX-induced cardiomyopathy remains unclear. Since accumulating evidence suggests that activation of the renin-angiotensin system is involved in the development of various types of cardiovascular remodeling, we examined the role of angiotensin II (Ang II) in DOX-induced cardiotoxicity using Ang II type 1a receptor (AT1) knockout (KO) mice. To examine the role of AT1 in the acute effects of DOX, we injected a single 20 mg/kg dose of DOX into AT1KO mice, wild type (WT) mice and WT mice treated with an AT1 antagonist, RNH-6270; to examine the role of AT1 in the chronic effects of DOX, we injected mice of the same groups with 1 mg/kg DOX once a week for 12 weeks. Echocardiography revealed that cardiac function was significantly impaired in WT mice, but not in AT1KO mice or WT mice administered RNH-6270, by both acute and chronic DOX treatment. Histological analysis showed that DOX induced myofibrillar loss and increased the number of apoptotic cells in WT mice, but not in AT1KO mice or WT mice administered RNH-6270. Expression of the ANP gene was downregulated by DOX treatment in WT mice, and this alteration was attenuated in AT1KO mice and in RNH-6270-treated mice. We conclude that the AT1-mediated Ang II signaling pathway plays an important role in DOX-induced cardiac impairment, suggesting that an AT1 antagonist can be used to prevent DOX-induced cardiomyopathy.     

吲哚美辛胃损伤中内皮素、一氧化氮、氧自由基的作用及其与胃动力的关系

目的 :研究吲哚美辛胃损伤中内皮素 (ET)、一氧化氮 (NO)、氧自由基的作用 ,以及胃动力对这种损伤的影响。方法 :雄性DS大鼠随机分 4组 :对照组、吲哚美辛 5mg/kg组、吲哚美辛 2 5mg/kg组、阿托品组 (阿托品 1mg/kg +吲哚美辛 2 5mg/kg)。吲哚美辛灌胃 ,灌胃前 10min阿托品皮下注射。取动脉血测ET、NO、丙二醛 (MDA)、超氧化物歧化酶 (SOD)、谷胱甘肽过氧化物酶 (GSH Px)水平 ,进行胃形态学观察。结果 :5mg/kg吲哚美辛不引起胃粘膜损伤 ,各检测指标与对照组无差异 ;2 5mg/kg吲哚美辛可引起胃粘膜显著出血性损伤 ,损伤指数为 38 5 7± 12 4 7,病理损伤积分为13 36± 3 37;ET 1和MDA水平升高 (P <0 0 1) ,NO、SOD、GSH Px水平降低 (P <0 0 1,P <0 0 1,P <0 0 5 ) ;阿托品组粘膜损伤较轻 ,损伤指数为 8 71± 3 35 ,病理损伤积分为 3 77± 1 0 4,ET 1含量和对照组无差异 ,MDA水平升高 (P <0 0 5 ) ,NO、SOD含量有所下降 (P <0 0 5 ) ,GSH Px含量无变化。结论 :吲哚美辛所致胃粘膜损伤中 ,ET 1和MDA生成增加起损害作用 ,内源性NO、SOD和GSH Px可清除氧自由基 ,有保护作用 ;阿托品对吲哚美辛所致胃粘膜损伤的保护作用 ,提示胃动力增加在吲哚美辛致溃疡中有重要作用。     

Melatonin reduces microvascular damage and insulin resistance in hamsters due to chronic intermittent hypoxia

Abstract: Obstructive sleep apnea (OSA) causes intermittent hypoxia (IH) associated with hypertension, insulin resistance and a systemic inflammatory response. We evaluated the effects of melatonin on vasodilation, capillary perfusion in hamster cheek pouch and insulin resistance, hypertension, and reactive oxygen species (ROS) and nitrate/nitrite levels after IH for 4 wk. Syrian hamsters were divided into four groups: control group (CON), IH group, and melatonin (10 mg/kg) intraperitoneally administered daily for 4 wk/30 min before intermittent air (MEL) or IH (IH + MEL) exposure. IH alone caused elevated blood pressure, increased hematocrit, fasting hyperglycemia, elevated ROS and nitrite/nitrate levels, and vasoconstriction and reduced microvascular perfusion. Melatonin treatment of IH‐exposed animals decreased blood pressure, blood glucose, and ROS and nitrite/nitrate levels, and increased vasodilation and capillary perfusion. An oral glucose tolerance test was performed after 4 wk of IH. During the last 30 min of the hyperinsulinemic euglycemic clamp, blood glucose, and insulin levels were identically matched between groups, but the glucose infusion rate was significantly reduced in IH (29.9 ± 1.9 mg/kg/min) versus IH + MEL group (45.4 ± 1.5 mg/kg/min, P < 0.05) demonstrating a decrease in insulin sensitivity. These results suggest that ROS and nitrite/nitrate levels play important roles in the microvascular dysfunction in IH and that this process is attenuated by melatonin. In conclusion, protection induced by melatonin against functional and metabolic impairment in IH is related to the regulation of ROS and nitrite/nitrate levels in the microcirculation. These observations may have importance to OSA pathological changes.     

硒锰对全血谷胱甘肽过氧化物酶活性影响的动态观察

本文用克山病病区粮，以及在病区粮基础上加硒（０．４ｍｇ／ｋｇ）、锰（１００ｍｇ／ｋｇ），喂养大鼠８周，对大鼠全血谷胱甘肽过氧化物酶（ＧＳＨ—Ｐｘ）活性进行动态观察，结果表明：病区粮和病区粮加锰饲料均可以使大鼠全血ＧＳＨ—Ｐｘ活性显著下降，加锰组下降的幅度更大；病区粮加硒使ＧＳＨ—Ｐｘ活性升高。相关分析表明：实验８周时．血硒浓度同ＧＳＨ—Ｐｘ活性呈显著正相关；血锰浓度与ＧＳＨ—Ｐｘ活性未见相关性。提示标通过对硒的作用来影响ＧＳＨ—Ｐｘ的活性，硒和锰之间存在相互作用。     

Dexrazoxane in patients with B-lymphomas or acute leukemias in the 2nd complete remission enables further therapy with cardiotoxic anthracyclines over recommended cumulative doses

Daunorubicin (DNR) and doxorubicin (DOX) have significant antitumor activity in acute myeloid leukemias (AML) and non-Hodgkin's lymphomas (NHL) but their use is limited by their life-threatening cumulative dose related cardiotoxicity. It is generally recommended not to administer DOX or DNR to patients in doses greater than 500 mg/sqm or 700 mg/sqm, respectively. the aim of the study was to follow up cardiotoxicity and efficacy of DNR or DOX above these limits in the 2nd complete remission (CR) patients pretreated with anthracyclines when they were given 30 minutes after cardioprotective agent dexrazoxane (DRZ) in the ratio 1:10 of DZR. Results: Two patients (54 and 53 years old) with mantle cell or diffuse large cell B-NHL, stage IV, who had relapsed after 6-8 cycles of classical CHOP therapy, reached their 2nd CR after 2-3 cycles of IDEA therapy (ifosfamide 1000 mg/sqm/day x 4, dexamethasone 30 mg/sqm/day x 4, etoposide 75 mg/sqm/day x 4, DOX 30 mg/sqm/day on days 1 and 3). Then they received further 3 cycles IDEA with DRZ 300 mg/sqm before every dose of DOX. After cumulative doses of DOX 600 mg/sqm and 700 mg/sqm these patients survived 12 months in their 2nd CR without significant signs of cardiotoxicity, even after their successful autologous peripheral stem cells transplantation. Their left ventricular ejection fraction (LVEF) remained above 60%. Six patients with AML in their 2nd CR were treated with consolidation cycles consisting of 10 high doses of cytosine arabinoside (2000 mg/sqm/12 hr) plus 2 doses of DNR 45 mg/sqm on the day 4 and 5. Two patients received cumulative doses corresponding to 1300 mg/sqm and 1000 mg/sqm of DNR, the other received DNR doses 550-850 mg/sqm. No signs of significant cardiotoxicity were observed in all 6 patients and their LVEF remained over 50%. One of two patients, transplanted with HLA-identical sibling bone marrow in her 2nd complete remission (CR), is still 8 years in her 2nd CR. Dexrazoxane enables to administer anthracyclines in doses over the recommended cumulative ones in pretreated patients with B-NHL or AML in their 2nd CR with the follow-up of their LVEF.     

Melatonin ameliorates experimental hepatic fibrosis induced by carbon tetrachloride in rats

AIM： To investigate the protective effects of melatonin on carbon tetrachloride （CCl4）-induced hepatic fibrosis in experimental rats.
METHODS： All rats were randomly divided into normal control group, model control group treated with CCl4 for 12 wk, CCl4 ＋ NAC group treated with CCl4 ＋ NAC （100 mg/kg, i.p.） for 12 wk, CCl4 ＋ MEL-1 group treated with CCl4 ＋ melatonin （2.5 mg/kg） for 12 wk, CCl4 ＋ MEL-2 group treated with CCl4 ＋ melatonin （5.0 mg/kg） for 12 wk, and CCl4 ＋ MEL-3 group treated with CCl4 ＋ melatonin （10 mg/kg）. Rats in the treatment groups were injected subcutaneously with sterile CCl4 （3 mL/kg, body weight） in a ratio of 2：3 with olive oil twice a week. Rats in normal control group received hypodermic injection of olive oil at the same dose and frequency as those in treatment groups. At the end of experiment, rats in each group were anesthetized and sacrificed. Hematoxylin and eosin （HE） staining and Van Gieson staining were used to examine changes in liver pathology. Serum activities of alanine aminotransferase （ALT）, aspartate aminotransferase （AST） and protein concentration weremeasured with routine laboratory methods using an autoanalyzer. Hydroxyproline （HYP） content in liver and malondialdehyde （MDA） and glutathione peroxidase （GPx） levels in liver homogenates were assayed by spectrophotometry. Serum hyaluronic acid （HA）, laminin （LN）, and procollagen Ⅲ N-terminal peptide （PⅢNP） were determined by radioimmunoassay.
RESULTS： Pathologic grading showed that the fibrogenesis was much less severe in CCl4 ＋ MEL3 group than in model control group （u = 2.172, P 〈 0.05）, indicating that melatonin （10 mg/kg） can significantly ameliorate CCl4-induced hepatic fibrotic changes. The serum levels of ALT and AST were markedly lower in CCl4 ＋ MEL treatment groups （5, 10 mg/kg） than in model control group （ALT： 286.23 ± 121.91 U/L vs 201.15 ± 101.16 U/L and 178.67 ± 103.14 U/L, P = 0.028, P = 0.007; AST： 431.00 ± 166.35 U/L vs 321.23 ± 162.48 U/L and 292.42 ± 126.23 U/L, P = 0.043, P = 0.013）. Similarly, the serum laminin （LN） and hyaluronic acid （HA） levels and hydroxyproline （HYP） contents in liver were significantly lower in CCl4 ＋ MEL-3 group （10 mg/kg） than in model control group （LN： 45.89 ± 11.71 μg/L vs 55.26 ± 12.30 μg/L, P = 0.012; HA： 135.71±76.03 μg/L vs 201.10 ± 68.46 μg/L, P = 0.020; HYP： 0.42 ± 0.08 mg/g tissue vs 0.51 ± 0.07 mg/g tissue, P = 0.012）. Moreover, treatment with melatonin （5, 10 mg/kg） significantly reduced the MDA content and increased the GPx activity in liver homogenates compared with model control group （MDA： 7.89 ± 1.49 noml/mg prot vs 6.29 ±1.42 noml/mg prot and 6.25 ±2.27 noml/mg prot, respectively, P = 0.015, P = 0.015; GPx： 49.13 ±8.72 U/mg prot vs 57.38 ±7.65 U/mg prot and 61.39 ±13.15 U/mg prot, respectively, P = 0.035, P = 0.003）.
CONCLUSION： Melatonin can ameliorate CCl4 -induced hepatic fibrosis in rats. The protective effect of melatonin on hepatic fibrosis may be related to its antioxidant activities,