Antianginal effects of lercanidipine on the vasopressin or methacholine induced anginal model in rats

The antianginal effects of lercanidipine, a newly synthesized 1,4-dihydropyridine derivative calcium channel antagonist, were evaluated in experimental angina model rats and the effects were compared with those of nifedipine, benidipine and amlodipine. In the vasopressin-induced angina model, intravenous administration of lercanidipine dose-dependently suppressed vasopressin-induced ST-depression. Amlodipine barely suppressed it, while benidipine, at the same dose, completely suppressed it. Nifedipine had a potency between that of amlodipine and benidipine. Oral administration of lercanidipine showed similar effects to the intravenous administration test on ST change. High doses of amlodipine, benidipine and nifedipine suppressed ST-depression by almost 100%. In the methacholine-induced angina model, lercanidipine suppressed the ST elevation dose dependently. Amlodipine barely suppressed it, while benidipine at 30 microg/kg effected almost total suppression. Nifedipine had a potency between that of amlodipine and benidipine. Intraduodenal administration of lercanidipine also suppressed the ST-elevation dose dependently. Nifedipine, benidipine and amlodipine at 10 mg/kg all markedly suppressed the elevation. Lercanidipine was more potent than the other calcium channel antagonists tested. In conclusion, it was explicitly demonstrated that lercanidipine exerts potent protective effects on the ischemic electrocardiography (ECG) changes in a variety of putative angina pectoris models in rats. An antispasmolytic coronary vasodilating action may be involved in the mechanism. It is expected that lercanidipine will be useful as an antianginal agent.     

Comparison of the cardioprotective and renoprotective effects of the L/N‐type calcium channel blocker,cilnidipine, in adriamycin‐treated spontaneously‐hypertensive rats

Cilnidipine is an L/N‐type calcium channel blocker (CCB). The effects of cilnidipine on N‐type channels give it unique organ‐protective properties via the suppression of hyperactivity in the sympathetic nervous system (SNS) and renin‐angiotensin‐aldosterone system (RAAS). In the present study, we compared the effects of cilnidipine and amlodipine (an L‐type CCB) on cardiac and renal functions in spontaneously‐hypertensive rats injected with adriamycin (ADR). After the weekly administration of ADR for 3 weeks, spontaneously‐hypertensive rats were orally administered cilnidipine (20 mg/kg per day), amlodipine (3 mg/kg per day), or vehicle once daily for 4 weeks. A control group received saline rather than ADR, followed by vehicle for 4 weeks. Cilnidipine and amlodipine produced similar reductions in blood pressure after 4 weeks. Cilnidipine ameliorated ADR‐induced heart and kidney damage, whereas amlodipine slightly improved cardiac echocardiographic parameters, but did not protect against ADR‐induced renal damage. Cilnidipine (but not amlodipine) suppressed the reflex SNS and RAAS hyperactivity caused by their antihypertensive effects. Furthermore, cilnidipine and amlodipine treatment decreased the urinary levels of adrenocortical hormones. The protective effects of cilnidipine against ADR‐induced renal and cardiac dysfunction might be associated with its blockade of N‐type calcium channels, in addition to its pleiotropic actions, which include the inhibition of the RAAS.     

Effects of benidipine in a rat model for experimental angina

To compare the antianginal effects of 1,4-dihydropyridine-type calcium-channel blockers, we evaluated the effects of benidipine, amlodipine, nifedipine, and efonidipine on vasopressin-induced myocardial ischemia in rats, an experimental model of angina. Intravenous administration of benidipine (3 microg/kg), amlodipine (1000 microg/kg), and nifedipine (100 microg/kg) suppressed the vasopressin-induced S-wave depression, an index of myocardial ischemia. Efonidipine (100 microg/kg, i.v.) tended to inhibit the S-wave depression. At the antianginal dose of each drug, amlodipine, nifedipine, and efonidipine decreased blood pressure significantly, whereas benidipine had little effect on blood pressure at a dose of 3 microg/kg. These results indicate that benidipine, unlike the other 1,4-dihydropyridine-type calcium-channel blockers examined in this study, inhibits vasopressin-induced coronary vasospasm with fewer undesirable effects such as hypotension in rats, suggesting that benidipine may be useful in the treatment of angina pectoris.     

Antioxidative effects of benidipine hydrochloride in patients with hypertension independent of antihypertensive effects. Relationship between blood pressure and oxidative stress

This study investigated the significance of measuring plasma level of thiobarbituric acid reactive substance (TBARS) in patients with hypertension and compared the clinical effects of benidipine hydrochloride (CAS 91599-74-5, Coniel) and amlodipine besylate (CAS 111470-99-6) on plasma TBARS. At first, blood pressure and plasma TBARS were measured in 85 untreated patients (48 males and 37 females, 68 years old on average) with at least one risk factor of cardiovascular disease to investigate factors which had influence on plasma TBARS. As the result, plasma TBARS was significantly higher in those with hypertension, which was also true when adjusted for other factors (r = 0.359, p< 0.01). Among these patients, benidipine hydrochloride at the dose of 4 mg/day was administered to 49 patients with hypertension or angina pectoris. All patients stratified for each factor showed significantly decreased plasma TBARS after benidipine hydrochloride treatment. Second, 40 untreated patients with essential hypertension were randomly assigned to the amlodipine group (5-7.5 mg/day) or benidipine group (4-8 mg/day) to compare the plasma TBARS levels. Plasma TBARS levels were significantly decreased in both groups. The amlodipine group showed a positive correlation between the decrease in plasma TBARS level and those in both diastolic and systolic blood pressures after treatment. On the other hand, benidipine hydrochloride decreased plasma TBARS to a greater degree than both diastolic and systolic blood pressures. These findings suggest that patients with hypertension have high plasma TBARS, and benidipine hydrochloride decreases not only blood pressure but also oxidative stress in the clinical practice.     

Aged garlic extract protects against doxorubicin-induced cardiotoxicity in rats

Clinical uses of doxorubicin (DOX), a highly active anticancer agent, are limited by its severe cardiotoxic side effects associated with increased oxidative stress and apoptosis. In this study we investigated whether aged garlic has protective effects against doxorubicin-induced free radical production and cardiotoxicity in male rats. A single dose of doxorubicin (25 mg/kg) caused increased both serum cardiac enzymes LDH and CPK activities and a significant increase malonyldialdehyde (MDA) in plasma. However, pretreatment of rats with aged garlic extract (250 mg/kg) for 27 days before doxorubicin therapy, reduced the activity of both enzymes, and significantly decreased of MDA production in plasma.     

Effects of telmisartan or amlodipine monotherapy versus telmisartan/amlodipine combination therapy on vascular dysfunction and oxidative stress in diabetic rats

Our previous studies identified potent antioxidant effects and improvement of vascular function by telmisartan therapy in experimental diabetes and nitrate tolerance. The present study compared the beneficial effects of single telmisartan or amlodipine versus telmisartan/amlodipine combination therapy (T+A) in streptozotocin (STZ)-induced type 1 diabetic rats. Male Wistar rats were injected once with STZ (60 mg/kg, i.v.) and 1 week later the drugs (telmisartan, amlodipine, or T+A) were administrated orally by a special diet (2.5–5 mg?kg^?1?day^?1) for another 7 weeks. We only observed a marginal beneficial on-top effect of T+A therapy over the single drug regimen that was most evident in the improvement of endothelial function (acetylcholine response) and less pronounced in the reduction of whole blood, vascular and cardiac oxidative stress (blood leukocyte oxidative burst, aortic dihydroethidine and 3-nitrotyrosine staining, as well as cardiac NADPH oxidase activity and uncoupling of endothelial nitric oxide synthase) in diabetic rats. These effects on oxidative stress parameters were paralleled by those on the expression pattern of NADPH oxidase and nitric oxide synthase isoforms. In addition, development of mild hypotension in the T+A-treated rats was observed. Reasons for this moderate synergistic effect of T+A therapy may be related to the potent beneficial effects of telmisartan alone and the fact that amlodipine and telmisartan share similar pathways to improve endothelial function. Moreover, hypotension in the T+A-treated rats could partially antagonize the beneficial additive effects by counter-regulatory mechanisms (e.g., activation of the renin–angiotensin–aldosterone system).     

Effect of amlodipine,lisinopril and allopurinol on acetaminophen-induced hepatotoxicity in rats

BackgroundExposure to chemotherapeutic agents such as acetaminophen may lead to serious liver injury. Calcium deregulation, angiotensin II production and xanthine oxidase activity are suggested to play mechanistic roles in such injury.ObjectiveThis study evaluates the possible protective effects of the calcium channel blocker amlodipine, the angiotensin converting enzyme inhibitor lisinopril, and the xanthine oxidase inhibitor allopurinol against experimental acetaminophen-induced hepatotoxicity, aiming to understand its underlying hepatotoxic mechanisms.Material and methodsAnimals were allocated into a normal control group, a acetaminophen hepatotoxicity control group (receiving a single oral dose of acetaminophen; 750 mg/kg/day), and four treatment groups receive N-acetylcysteine (300 mg/kg/day; a reference standard), amlodipine (10 mg/kg/day), lisinopril (20 mg/kg/day) and allopurinol (50 mg/kg/day) orally for 14 consecutive days prior to acetaminophen administration. Evaluation of hepatotoxicity was performed by the assessment of hepatocyte integrity markers (serum transaminases), oxidative stress markers (hepatic malondialdehyde, glutathione and catalase), and inflammatory markers (hepatic myeloperoxidase and nitrate/nitrite), in addition to a histopathological study.ResultsRats pre-treated with amlodipine, lisinopril or allopurinol showed significantly lower serum transaminases, significantly lower hepatic malondialdehyde, myeloperoxidase and nitrate/nitrite, as well as significantly higher hepatic glutathione and catalase levels, compared with acetaminophen control rats. Serum transaminases were normalized in the lisinopril treatment group, while hepatic myeloperoxidase was normalized in the all treatment groups. Histopathological evaluation strongly supported the results of biochemical estimations.ConclusionAmlodipine, lisinopril or allopurinol can protect against acetaminophen-induced hepatotoxicity, showing mechanistic roles of calcium channels, angiotensin converting enzyme and xanthine oxidase enzyme in the pathogenesis of hepatotoxicity induced by acetaminophen.     

Amlodipine alleviates cisplatin-induced nephrotoxicity in rats through gamma-glutamyl transpeptidase (GGT) enzyme inhibition,associated with regulation of Nrf2/HO-1, MAPK/NF-κB,and Bax/Bcl-2 signaling

BackgroundThe therapeutic utility of the effective chemotherapeutic agent cisplatin is hampered by its nephrotoxic effect. We aimed from the current study to examine the possible protective effects of amlodipine through gamma-glutamyl transpeptidase (GGT) enzyme inhibition against cisplatin nephrotoxicity.MethodsAmlodipine (5 mg/kg, po) was administered to rats for 14 successive days. On the 10^th day, nephrotoxicity was induced by a single dose of cisplatin (6.5 mg/kg, ip). On the last day, blood samples were collected for estimation of kidney function, while kidney samples were used for determination of GGT activity, oxidative stress, inflammatory, and apoptotic markers, along with histopathological evaluation.ResultsAmlodipine alleviated renal injury that was manifested by significantly diminished serum creatinine and blood urea nitrogen levels, compared to cisplatin group. Amlodipine inhibited GGT enzyme, which participates in the metabolism of extracellular glutathione (GSH) and platinum-GSH-conjugates to a reactive toxic thiol. Besides, amlodipine diminished mRNA expression of NADPH oxidase in the kidney, while enhanced the anti-oxidant defense by activating Nrf2/HO-1 signaling. Additionally, it showed marked anti-inflammatory response by reducing expressions of p38 mitogen-activated protein kinase (p38 MAPK) and nuclear factor-kappa B (NF-κB), with subsequent down-regulation of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and vascular cell adhesion molecule-1 (VCAM-1). Moreover, amlodipine reduced Bax/Bcl-2 ratio and elevated hepatocyte growth factor (HGF), thus favoring renal cell survival.ConclusionsEffective GGT inhibition by amlodipine associated with enhancement of anti-oxidant defense and suppression of inflammatory signaling and apoptosis support our suggestion that amlodipine could replace toxic GGT inhibitors in protection against cisplatin nephrotoxicity.     

姜黄素对鼠体内SOD活性和MDA含量的影响

目的：观察姜黄素对成年小鼠及老年大鼠体内超氧化物歧化酶（ＳＯＤ）和丙二醛（ＭＤＡ）含量的影响。方法：选用成年ＮＩＨ小鼠，每日腹腔注射姜黄素共７ｄ，观察血浆、脑及肝脏组织的ＳＯＤ活性及ＭＤＡ含量。选用雄性ＳＤ老年大鼠（＞２８月龄），用０．０２％姜黄素水溶液作为饮水，连续给药９ｗｋ，动态观察给药前及给药后９ｗｋ内血浆中ＳＯＤ和ＭＤＡ的含量。结果：姜黄素给药小鼠血浆及脑组织的ＭＤＡ含量下降，血浆、脑及肝脏组织的ＳＯＤ活性均明显提高，呈现一定的剂量依赖关系。老年大鼠给药后血浆中的ＭＤＡ含量明显降低，血浆ＳＯＤ的活性在给药后３ｗｋ呈现一过性升高。结论：姜黄素有抑制成年小鼠和老年大鼠体内脂质过氧化过程的作用，该作用除了与其本身的抗自由基效应有关外，还与其提高机体的ＳＯＤ活性作用有一定关系。     

螺旋藻对高同型半胱氨酸血症大鼠氧化应激水平及动脉损伤的影响

目的研究螺旋藻对高同型半胱氨酸血症（HHcy）大鼠氧化应激水平及动脉损伤的影响。方法雄性Wistar大鼠60只随机分成6组：正常对照组、HHcy模型组、螺旋藻低、中、高剂量组和叶酸组，每组10只均喂以普通鼠饲料。除正常对照组外，其余各组均给予1g／（ks·d）L-蛋氨酸灌胃，同时螺旋藻各剂量组与叶酸组以灌胃方式给予相应药物。连续喂养12周后，以高效液相色谱法测定血浆同型半胱氨酸（Hcy）水平。以硫代巴比妥酸反应比色法测定血浆丙二醛水平，以黄嘌呤氧化酶法检测血浆超氧化物歧化酶（SOD）活力，以光镜检测腹主动脉组织学变化并以免疫组化方法检测大鼠腹主动脉增殖细胞核抗原（PCNA）蛋白表达。结果HHcy模型组大鼠血浆Hey水平、丙二醛浓度和SOD活力均明显高于正常对照组（P〈0．05和P〈0．01）。以螺旋藻低、中、高剂量和叶酸干预后，血浆Hcy和丙二醛浓度均较HHcy模型组显著下降（P〈0．05，P〈0．01），SOD活力较正常对照组有升高趋势。组织学检测发现，HHcy模型组大鼠腹主动脉受损，PCNA阳性细胞数量与正常对照组相比明显增加（P〈0．05），而螺旋藻各剂量组腹主动脉损伤轻于HHcy模型组，PCNA阳性细胞数量亦较HHcy模型组减少（P〈0．05）。结论螺旋藻能有效降低HHcy大鼠血浆Hey浓度，降低HHcy所引起的氧化应激反应，对HHcy所致的动脉损伤具有保护作用。     

Amlodipine in patients with angina uncontrolled by atenolol

Summary Dihydropyridine calcium antagonists are established second line treatment for angina uncontrolled by -adrenergic blockers. Amlodipine is a recently introduced, dihydropyridine with a long half life. In a double blind, placebo controlled, cross over trial we assessed the efficacy and safety of amlodipine in 20 patients with persistent angina despite treatment with atenolol. 17 male patients (mean age 58 y) completed the study. Two patients were withdrawn during placebo because of worsening angina and one withdrew whilst on amlodipine because of palpitations.Compared with baseline, amlodipine prolonged exercise time to S-T segment depression by a median of 12.5%; significantly more than was found with placebo (median 0%). The improvement in exercise time and time to angina also tended to be greater for amlodipine than placebo. GTN consumption, at a median of 1.3/week, was significantly less with amlodipine than placebo (2.8). Attacks of angina were also reduced.Standing systolic and diastolic blood pressures and sitting systolic blood pressure were lower with amlodipine than placebo. Heart rate did not change. There was no change in cardiac output (measured by doppler aortovelography) when amlodipine was added to atenolol. Holter monitor measurements of 24 h maximum and minimum heart rate, heart rate variation and extrasystole counts were the same for amlodipine and placebo.In conclusion, amlodipine is effective in patients with angina inadequately controlled by atenolol alone, and does not interfer with cardiac rhythm or function.     

A 6-week double-blind comparison of amlodipine and placebo in patients with stable exertional angina pectoris receiving concomitant beta-blocker therapy

This study was a multicenter, double-blind comparison of the antianginal efficacy and safety of amlodipine and placebo as adjunctive therapy with constant recommended maintenance doses of beta-blockers. Patients with stable exertional angina pectoris were randomized to placebo or amlodipine at a starting dose of 5 mg once daily. The amlodipine dose was adjusted to 10 mg daily after 2 weeks if angina attacks were not abolished. Antianginal efficacy was assessed throughout the study with angina diaries, investigators' and patients' global evaluations, and with bicycle exercise tests during a placebo run-in period (baseline) and after 2 and 6 weeks of double-blind treatment. On baseline-final analysis, the exercise time to angina onset increased by 13% with amlodipine compared to 6% with placebo (p < 0.05). The total exercise time increased by 11% on amlodipine compared with 2% on placebo, though this difference did not reach statistical significance. Angina attack frequency and nitroglycerin consumption were both reduced by adding amlodipine to beta-blocker treatment. Amlodipine in combination with beta-blocker therapy was well tolerated, with a low incidence of side effects and laboratory test abnormalities. The study showed clearly that addition of amlodipine to beta-blocker therapy in patients with stable angina pectoris was well tolerated and gave improved antianginal efficacy.     

Chronic blockade of angiotensin AT1 receptors improves cardinal symptoms of metabolic syndrome in diet-induced obesity in rats

Background and Purpose

AT₁ receptor antagonists decrease body weight gain in models of murine obesity. However, fewer data are available concerning the anti-obesity effects of these antagonists, given as a treatment after obesity had been established.

Experimental Approach

In spontaneously hypertensive rats, obesity was established by cafeteria diet (CD) feeding for 19 weeks. Rats were then were treated with telmisartan (8 mg·kg⁻¹·d⁻¹) or amlodipine (10 mg·kg⁻¹·d⁻¹; serving as blood pressure control) or telmisartan + amlodipine (2 + 10 mg·kg⁻¹·d⁻¹; to control for dose-dependency) for 17 weeks. Rats receiving only chow (C_chow) or CD-fed rats treated with vehicle (C_CD) served as controls.

Key Results

The CD feeding induced obesity, hyperphagia, hyperlipidaemia, and leptin and insulin resistance. Telmisartan reduced the CD-induced increase in body weight and abdominal fat mass. Whereas energy intake was higher rather than lower, the respiratory ratio was lower. After telmisartan, leptin-induced energy intake was reduced and respiratory ratio was increased compared with C_CD rats. Telmisartan also decreased plasma levels of triglycerides, free fatty acids and low-density lipoprotein. Amlodipine alone or the combination telmisartan + amlodipine did not affect body weight and eating behaviour. Telmisartan, but not amlodipine and telmisartan + amlodipine, improved glucose utilization. The decrease in BP reduction was almost the same in all treatment groups.

Conclusions and Implications

Telmisartan exerted anti-obesity effects and restored leptin sensitivity, given as a treatment to rats with obesity. Such effects required high doses of telmisartan and were independent of the decrease in blood pressure.     

T-type and L-type calcium channel blockers exert opposite effects on renin secretion and renin gene expression in conscious rats

1. This study aimed to investigate and to compare the effects of pharmacological T-type calcium channel and of L-type calcium channel blockade on the renin system. To this end, male healthy Sprague-Dawley rats were treated with the T-channel blocker mibefradil or with the L-channel blocker amlodipine at doses of 5 mg kg⁻¹, 15 mg kg⁻¹ and 45 mg kg⁻¹ per day for four days and their effects on plasma renin activity (PRA) and kidney renin mRNA levels were determined.
2. Whilst amlodipine lowered basal systolic blood pressure at 5 mg kg⁻¹, mibefradil had no effect on basal blood pressure in the whole dose range examined. Amlodipine dose-dependently induced up to 7 fold elevation of PRA and renin mRNA levels. Mibefradil significantly lowered PRA and renin mRNA levels at 5 mg kg⁻¹ and moderately increased both parameters at a dose of 45 mg kg⁻¹, when PRA and renin mRNA levels were increased by 100% and 30%, respectively. In primary cultures of renal juxtaglomerular cells neither amlodipine nor mibefradil (0.1–10 μM) changed renin secretion.
3. In rats unilateral renal artery clips (2K-1C) mibefradil and amlodipine at doses of 15 mg kg⁻¹ day⁻¹ were equally effective in lowering blood pressure. In contrast mibefradil (5 mg kg⁻¹ and 15 mg  kg⁻¹ day⁻¹) significantly attenuated the rise of PRA and renin mRNA levels, whilst amlodipine (15 mg kg⁻¹) additionally elevated the rise of PRA and renin mRNA levels in response to renal artery clipping.
4. These findings suggest that T-type calcium channel blockers can inhibit renin secretion and renin gene expression in vivo, whilst L-type calcium channel blockers act as stimulators of the renin system. Since the inhibitory effect of T-type antagonists is apparent in vivo but not in vitro, one may infer that the effect on the renin system is indirect rather than directly mediated at the level of renal juxtaglomerular cells.

     

糖尿病并发症相关性氧化应激的实验研究

目的链脲佐菌素(STZ)诱导大鼠1型糖尿病模型的基础上,探讨糖尿病氧化应激指标的变化。方法采用一次性腹腔注射STZ的方法,监测不同时点大鼠的空腹血糖、体质量及血浆中的丙二醛(MDA)和超氧化物歧化酶(SOD)等指标,并对结果进行统计学处理。结果大鼠注射STZ 72h后血糖值达到成模标准,并逐渐出现糖尿病表现,观察7周,始终满足成模标准,未见转复。DM组大鼠肾脏及肝脏肥大指数较CON组显著增加。氧化应激相关指标测定表明,较对照组相比,实验组大鼠血浆中脂质过氧化产物MDA水平显著升高,而SOD水平显著下降。结论本实验Ⅰ型糖尿病模型大鼠造模成功且模型稳定,氧化应激指标改变。     

Deciphering the role of ferulic acid against streptozotocin-induced cellular stress in the cardiac tissue of diabetic rats

The cardiomyocytes are one of the major sources of hyperglycemia induced ROS generation. The present study focuses on the ameliorative role of ferulic acid in combating cardiac complications in diabetic rats. Induction of diabetes by STZ in male Wistar rats (at a dose of 50 mg kg⁻¹ body wt, i.p.) reduced body weight and plasma insulin level, enhanced blood glucose, disturbed the intra-cellular antioxidant machineries and disintegrated the normal radiation pattern of cardiac muscle fibers. Induction of ER stress (up-regulation in the levels of CHOP, GRP78, eIF2α signaling, increased calpain-1 expression), caspase-3 activation, PARP cleavage and DNA fragmentation were evidenced from immunoblot analyses and DNA fragmentation assay. However, ferulic acid administration, (at a dose of 50 mg kg⁻¹ body wt, orally for eight weeks) in post-hyperglycemia could reverse such adverse effects. Also, the molecule increased GLUT-4 translocation to the cardiac membrane by enhanced phosphorylation of PI3Kinase, AKT and inactivation of GSK-3β thereby altering the hyperglycemic condition in the cardiac tissue of diabetic rats. Therefore, as a potential therapeutic, ferulic acid, exhibiting antioxidant and hypoglycemic effects, may hold promise in circumventing stress mediated diabetic cardiomyopathy in rats.     

Effects of carnosine on prooxidant–antioxidant status in heart tissue,plasma and erythrocytes of rats with isoproterenol-induced myocardial infarction

Rats were injected with isoproterenol (ISO; 110 mg/kg, ip, 2 doses, 24 h interval) to induce acute myocardial infarction (AMI) and were sacrificed 6 and 24 h after the last ISO injection. The heart tissue, plasma and erythrocytes of these rats were evaluated for cardiac markers and oxidative stress parameters. Levels of cardiac troponin T (cTnT) and the activities of creatine kinase (CK), lactate dehydrogenase (LDH), and aspartate aminotransferase (AST) in plasma were increased 6 and 24 h after ISO treatment. The levels of malondialdehyde (MDA), diene conjugate (DC), and protein carbonyl (PC) were increased in heart tissue and plasma, while levels of erythrocyte MDA and glutathione (GSH) and plasma ferric reducing antioxidant power (FRAP) were also increased. However, GSH levels and the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) decreased in heart tissue of rats with AMI. We also investigated the effects of carnosine (CAR) treatment on these parameters 24 h after the last ISO injection. CAR (250 mg/kg/day; ip) treatments were carried out either 10 days before ISO injection or 2 days concomitant with ISO. Pretreatment with CAR decreased plasma LDH and AST activities and ameliorated cardiac histopathological changes in ISO-treated rats. Cardiac MDA, DC and PC levels decreased, but GSH levels and SOD and GSH-Px activities increased. However, the increases in plasma MDA and PC levels as well as erythrocyte H₂O₂-induced MDA and GSH levels did not change due to CAR pretreatment. In conclusion, our findings indicate that CAR pretreatment may have protective effects on ISO-induced cardiac toxicity by decreasing oxidative stress.     

Cinnamon modulates the pharmacodynamic & pharmacokinetic of amlodipine in hypertensive rats

The objective of this study was to investigate the effects of cinnamon on the pharmacodynamic (PD) & pharmacokinetic (PK) of amlodipine in hypertensive rats. The hypertensive control group of Wistar rats received L-NAME (40 mg/kg, daily, orally) only. The cinnamon group of rats was treated with cinnamon (200 mg/kg, daily, orally) along with L-NAME. Following 14 days treatment period, blood pressures of rats were monitored at designated intervals over 24 h utilizing a tail-cuff system for measuring blood pressure. To assess the oral PK; amlodipine was administered as a single oral dose of 1 mg/kg to rats and blood samples were collected at specified intervals over 24 h and analysed by UPLC-LC MS/MS.Synergistic decreased in rat’s blood pressure was observed in presence of cinnamon + amlodipine. Simultaneous administration of cinnamon ameliorates the C_max and AUC_0-t of amlodipine, the C_max and AUC_0-t was 11.04 ± 1.01 ng/ml and 113.76 ± 5.62 ng h/ml for the cinnamon + amlodipine group as compared to 4.12 ± 0.49 ng/ml and 48.59 ± 4.28 ng h/ml for the amlodipine alone group. The study demonstrates that the use of cinnamon considerably decreases the blood pressure levels and enhances the PK parameters of amlodipine in hypertensive rats.     

水杨酸甲酯糖苷抗大鼠急性胸膜炎的作用研究

目的水杨酸甲酯糖苷(DL0309)是来源于民族药滇白珠的新型非甾体抗炎药,本实验的主要目的是评价其对角叉菜胶致大鼠胸膜炎模型的抗炎作用及其可能的机制。方法将48只♂SD大鼠按体重随机分为正常对照组、模型对照组、阳性对照组(地塞米松)、DL0309低、中、高剂量组。通过注射角叉菜胶,建立大鼠急性胸膜炎模型。造模后5 h处死大鼠,通过测定胸腔渗出液的体积,对渗出液中的白细胞计数,并测定渗出液中蛋白质的含量来观察药物对该模型的抗炎作用;通过测定渗出液中一氧化氮(NO)、肿瘤坏死因子(TNF-α)、白介素1β(IL-1β)和前列腺素E2(PGE2)以及血浆中超氧化物歧化酶(SOD)和丙二醛(MDA)的含量,来考察DL0309对该模型的抗炎作用机制。结果结果显示地塞米松和DL0309均可明显降低胸膜炎大鼠胸腔炎性渗出液的体积以及渗出液中的白细胞数量和蛋白质含量,同时对于胸腔炎性渗出液中的NO、TNF-α、IL-1β和PGE2的含量均有不同程度的抑制,能不同程度地降低血浆中MDA含量,升高SOD活力。结论 DL0309具有抗角叉菜胶诱导的大鼠急性胸膜炎作用。     

Commonly consumed and naturally occurring dietary substances affect biomarkers of oxidative stress and DNA damage in healthy rats.

The influence of black currant juice, Bowman-Birk protease inhibitor (BBI), kolaviron (a biflavonoid fraction of Garcinia kola seed), sugars, vitamin C and tert-butyl hydroperoxide on a wide range of biomarkers for oxidative stress, DNA damage and sugar or lipid metabolism has been investigated in male F 344 rats. The selected pro-oxidant control, tert-butyl hydroperoxide, significantly increased plasma and liver 2-amino-adipic semialdehyde (AAS), a marker of protein oxidation (p <0.05) whereas lipid oxidation assessed as malon dialdehyde (MDA) and DNA oxidation were not significantly increased. Feeding BBI also increased the level of oxidized protein in plasma and liver at the higher dose level (0.5%). No effect was observed at the lower dose level (0.25%), which even decreased lipid oxidation in plasma. BBI did not affect background levels of DNA strand breaks or oxidation (comets). In rats exposed to black currant juice, a statistically significant decrease in liver AAS and MDA was observed. This effect could not be explained by its content of sugars or of the known redox active constituent, vitamin C. The lowering effect of black currant juice on protein and lipid oxidation was similar in magnitude to that of the known liver protectant, kolaviron. In rats treated with kolaviron (200 mg/kg body weight), background AAS levels were significantly reduced in both plasma and liver whereas the effect on MDA only reached statistical significance in plasma. Kolaviron was the only extract tested which decreased oxidative damage to DNA in the liver. The erythrocyte antioxidant enzyme activities, catalase and glutathione peroxidase were decreased in rats treated with tert-butyl hydroperoxide (p <0.05) but were not affected by the other treatments. Black currant juice and sugars increased plasma triglyceride levels and black currant juice increased plasma cholesterol but neither of them nor any other treatment affected blood glucose, erythrocyte HbA1c or fructosamine. We conclude that markers of oxidative stress may be modified by several mechanisms after feeding rats with complex dietary factors and that both pro- and antioxidant effects may consequently be observed simultaneously after short-term feeding of antioxidant-rich foods, herb medicines, or known pro- and antioxidants.