The effect of natural infection with different Leptospira interrogans serovars on oxidative stress biomarkers and acute-phase responses in horses and cattle.

Leptospirosis is one of the important zoonotic bacterial diseases with a worldwide distribution that is often subclinical. We aimed to investigate the oxidant/antioxidant balance and acute-phase response in naturally infected horses and cattle with Leptospira interrogans. A total of 600 serum samples from horses and cattle were examined for L. interrogans antibodies using the microscopic agglutination test to determine anti-Leptospira IgG antibodies against a panel of eight important Leptospira antigens in Iran. Then, serum total antioxidant capacity, catalase, glutathione peroxidase, and malondialdehyde activities, and nitric oxide, total protein, serum amyloid A, haptoglobin, and albumin concentrations were measured in seropositive and seronegative samples. Serum catalase activities and malondialdehyde, serum amyloid A, and haptoglobin |concentrations in seropositive cattle and horses were significantly higher (P < .05) than in those that were seronegative. Antibody titers increased from 1:100 to ≥ 1:200 in cattle with L. interrogans infection, resulting in a decrease in the serum total antioxidant capacity (P < .05), an increase in serum glutathione peroxidase (P < .01) activity and nitric oxide (P < .05) , serum amyloid A (P < .01), and haptoglobin (P < .05) concentrations. Following the increase in the agglutinating antibody titers in horses infected with L. interrogans, the serum total antioxidant capacity (P < .01) decreased, and serum nitric oxide (P < .05), malondialdehyde (P < .05), and serum amyloid A (P < .01) concentrations were increased. In this study, horses and cattle had extensive changes in oxidant/antioxidant equilibrium and acute-phase protein concentrations when infected with L. interrogans. We also demonstrated a direct link between antibody titers and the type of leptospiral serovar using serum oxidative and inflammatory markers.

Reduce Muscle Fibrosis through Exercise via NRG1/ErbB2 Modification in Diabetic Rats.

Diabetic myopathy refers to the manifestations in the skeletal muscle as a result of altered glucose homeostasis which reflects as fibrosis. Since physical exercise has been indicated a protective strategy for improving glucose metabolism in skeletal muscle, we tested a hypothesis under which the endurance exercise training could reverse the produced skeletal muscle fibrosis by diabetes. Eight-week-old male Wistar rats were randomly assigned into four groups including healthy control (HC), healthy trained (HT), diabetic control (DC), and diabetic trained (DT) groups. Diabetes was induced by a single intraperitoneal injection of streptozotocin (STZ; 45 mg/kg). Rats in the HT and DT groups carried out an exercise program on a motorized treadmill for five days a week over six weeks. Skeletal muscle levels of NRG1and ErbB2 were measured by the Western blot method. Exercise training decreased blood glucose levels in the DT group. Induction of diabetes increased skeletal muscle fibrosis in both the fast extensor digitorum longus (EDL) and slow soleus muscles, while endurance training modified it in diabetic trained rats. Moreover, muscle NRG1and ErbB2 levels were increased in diabetic rats, while training modified muscle NRG1and ErbB2 levels in diabetic trained rats. Our study provides novel evidence that endurance training could modify skeletal muscle fibrosis through NRG1/ErbB2 modification in STZ-induced diabetic rats.

Delivery of vinblastine-containing niosomes results in potent in vitro/in vivo cytotoxicity on tumor cells.

Vinblastine (VB), as a chemotherapeutic agent, is widely used in treatment of different types of cancer. However, its clinical application is limited due to its low water solubility, side effects, and multidrug resistance. The aim of this study was to increase the therapeutic efficacy of VB using drug delivery systems. For this purpose, a PEGylated niosomal formulation of vinblastine (Pn-VB) was prepared by thin film hydration method and physicochemically characterized. Drug release pattern was performed by dialysis diffusion method. The cytotoxicity of Pn-VB was investigated against murine lung cancer TC-1 cells using MTT assay and its tumor inhibitory effect was evaluated in lung tumor-bearing C57BL/6 mice. Mean particle size, zeta potential, entrapment, and loading efficiency of niosomes were obtained to be about 234.3 ± 11.4 nm, -34.6 ± 4.2 mV, 99.92 ± 1.6%, and 2.673 ± 0.30%, respectively. While, the mean particle size and zeta potential for non-PEGylated niosomes were obtained about 212.4 nm and -31.4 mV, respectively. The in vitro release pattern of drug from niosomes showed a sustained release behavior. Pn-VB indicated a significant increase in toxicity against TC-l cells as compared to free VB. In animal model, Pn-VB exhibited stronger tumor inhibitory effect and longer life time in comparison to free VB. In conclusion, Pn-VB showed appropriate stability, high-entrapment efficacy, lower releasing rate, and stronger cytotoxic activity against lung cancer TC-1 cells as compared to free drug. Thus, the Pn-VB could be a promising formulation for delivery of vinblastine to tumor cells with enhanced drug bioavailability and therapeutic efficacy.

Synergistic effects of nitric oxide and exercise on revascularisation in the infarcted ventricle in a murine model of myocardial infarction.

It has been shown that density of microvessels decreases in the left ventricular after myocardial infarction (MI). The change of angiogenic and angiostatic factors as the main factors in revascularisation after exercise training in area at risk is not determined yet in MI. Therefore, the aim of the present study was the effect of exercise training and L-arginine supplementation on area at risk angiogenesis in myocardial infarction rat. Four weeks after surgery (Left Anterior Descending Coronary artery Ligation), myocardial infarction rats were divided into 4 groups: Sedentary rats (Sed-MI); L-arginine supplementation (La-MI); Exercise training (Ex-MI) and Exercise + L-arginine (Ex+La). Exercise training (ET) lasted for 10 weeks at 17 m/min for 10-50 min day(-1). Rats in the L-arginine-treated groups drank water containing 4 % L-arginine. After ET and L-arginine supplementation, ventricular function was evaluated and angiogenic and angiostatic indices were measured at ~1 mm from the edge of scar tissue (area at risk). Statistical analysis revealed that gene expression of VEGF as an angiogenic factor, angiostatin as an angiostatic factor and caspase-3 at area at risk decrease significantly in response to exercise training compared to the sedentary group. The capillary and arteriolar density in the Ex groups were significantly higher than those of the Sed groups. Compared to the Ex-MI group, the Ex+La group showed a markedly increase in capillary to fiber ratio. No significant differences were found in infarct size among the four groups, but cardiac function increased in response to exercise. Exercise training increases revascularization at area at risk by reduction of angiostatin. L-arginine supplementation causes additional effects on exercise-induced angiogenesis by preventing more reduction of VEGF gene expression in response to exercise. These improvements, in turn, increase left ventricular systolic function and decrease mortality in myocardial infarction rats.

Effect of normobaric hyperoxia on gentamicin-induced nephrotoxicity in rats.

OBJECTIVES: Gentamicin sulphate (GS) nephrotoxicity seems to be related to the generation of reactive oxygen species. There is evidence that oxygen preconditioning increases the activity of antioxidant enzymes. MATERIALS AND METHODS: Forty eight female rats were divided into 6 groups (n=8) as follows: group 1 was the control, group 2 received daily GS, groups 3,4 and 5 received oxygen 2 hr/day for 2 days, 4 hr/day for 2 days, 4 hr/day for 4 days, recpectively and then received daily GS, group 6 received oxygen 2 hr/day for 2 days and then received 2 hr oxygen before daily GS injection. Oxygen (with 90% purity) used at the flow rate of 4 l/min. GS administred for 8 days (100 mg/kg, IP). Tissue sections prepared from the left kidney, stained with PAS method and then studied hisopathologically and stereologically. The right kidneys were homogenized and the supernatants were prepared. Serum MDA, creatinine and urea, renal MDA, gluthatione and catalase activity were measured. The data were analyzed by Mann-Whitney U test at the significant level of P<0.05. RESULTS: Oxygen therapy significantly improves serum creatinine and urea, preserve tubular volume density, reduce tubular necrosis in groups 4 and 6 compared to group 2. Oxygen therapy significantly increases renal catalase in groups 4 and 6 compared to group 2. CONCLUSION: Pretreatment with normobaric hyperoxia and daily oxygen therapy improved gentamicin nephrotoxicity possibly via inhibition of lipid peroxidation and increasing the renal catalase activity but could not restore any parameter at the same levels as control group.

Effect of dimethyl sulfoxide on inhibition of post-ovariectomy osteopenia in rats.

There is increasing evidence that oxidative stress, due to estrogen deficiency, leads to osteopenia. In this study, dimethyl sulfoxide (DMSO), an antioxidant solvent, was used against post-ovariectomy osteopenia (PO) in rats. Forty female rats were divided into 5 groups randomly as follows: Sham, control group; OVX, ovariectomized group; DMSO1, ovariectomized injected DMSO (0.5 ml/kg/d ip); DMSO2, ovariectomized injected DMSO (1 ml/kg/day ip) and DMSO3, ovariectomized injected DMSO (2 ml/kg/d ip). DMSO therapy started 1 week after ovariectomy and continued for 13 weeks. After 13th weeks, sera were prepared, and then L4 vertebrae and right tibial bones rinsed in fixative. Serum bone alkaline phosphatase (BALP), osteocalcin, pyridinoline, malondialdehyde (MDA) and glutathione (GSH) were measured. Trabecular volume density, trabecular and cortex thickness were estimated. Osteoclast and osteoblast numbers were counted morphometrically. The data were analyzed by ANOVA and then post hoc Tukey test at p < 0.05. The increase of pyridinoline and decrease of BALP in DMSO injected groups were inhibited compared with OVX group (p < 0.05). In DMSO injected groups, decrease of bone density, trabecular volume density, thickness of trabecular and tibial cortex were inhibited compared with OVX group (p < 0.05). MDA decreased significantly in DMSO injected groups compared with OVX group. Osteoclast number decreased in DMSO injected groups compared with OVX group (p < 0.05). Osteoblast number did not show significant change in DMSO groups compared with OVX group. In conclusion, DMSO ameliorates PO through decrease of osteoclast number, osteoclast inhibition and osteoblast activation. These effects may probably be mediated via antioxidant property of DMSO.

Effect of rosmarinic acid on inhibition of gentamicin induced nephrotoxicity in rats.

The present investigation reports the effect of rosmarinic acid (RA), an antioxidant on gentamicin sulphate (GS)-induced renal oxidative damage in rats. Rosmarinic acid (RA) has been demonstrated to have antioxidant, free radical scavenger and anti-inflammatory effects. Twenty-eight Sprague-Dawley rats were divided in to four equal groups as follows: group 1 (control), group 2 (GS 100 mg/kg/d ip), group 3 (GS 100 mg/kg/d ip+RA 50 mg/kg/d) and group 4 (GS 100 mg/kg/d ip+RA 100 mg/kg/d). Treatments were administrated once daily for 12 days. After 12 days 24h urine was collected, blood was sampled and kidneys were removed. Serum and kidney tissue MDA assessed by thiobarbituric acid. Kidney paraffin sections (5 µm thickness) from the left kidney stained with periodic acid Schiff. Tubular necrosis was studied semiquantitatively and glomerular volume and volume density of proximal convoluted tubule (PCT) estimated stereologically. Kidney homogenize were prepared from right kidney. Serum creatinine, urea and kidney antioxidant enzymes activity were assessed by special kits. Data were compared by SPSS 13 software and Mann-Whitney test at p < 0.05. Co treatment of GS and RA (High dose) significantly decreased serum creatinine, MDA, urea, tubular necrosis (p < 0.05) and increase renal GSH, GPX, CAT, SOD, volume density of PCT and creatinine clearance significantly in comparison with GS group (p < 0.05). Treatment with RA (high dose) maintained serum creatinine, volume density of PCT, renal GSH, GPX, SOD and MDA as the same level as control group significantly (p < 0.05). In conclusion, RA alleviates GS nephrotoxicity via antioxidant activity, increase of renal GSH content and increase of renal antioxidant enzymes activity.

Effects of epigallocatechin gallate on tissue protection and functional recovery after contusive spinal cord injury in rats.

Recent studies revealed the neuroprotective effects of epigallocatechin gallate (EGCG) on a variety of neural injury .The purpose of this study was to determine the effects of EGCG on the tissue protection and behavioral improvement after spinal cord injury (SCI). Rats were randomly divided into four groups of 18 rats each as follows: sham-operated group, trauma group, and EGCG treatment groups (50 mg/kg, i.p., immediately and 1 hour after SCI). Spinal cord samples were taken 24 hours after injury and studied for determination of malodialdehyde (MDA) levels, immunohistochemistry of Bax and Bcl-2, and TUNEL reaction. Behavioral testing was performed weekly up to 6 weeks post-injury. Then, the rats were euthanized for histopathological assessment. The results showed that MDA levels were significantly decreased in EGCG treatment groups. Greater Bcl-2 and attenuated Bax expression could be detected in the EGCG-treated rats. EGCG significantly reduced TUNEL-positive rate. Also, EGCG significantly reduced the percentage of lesion area and improved behavioral function than the trauma group. On the basis of these findings, we propose that EGCG may be effective in protecting rat spinal cord from secondary injury.