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.     

Effect of caffeic acid derivatives on polychlorinated biphenyls induced hepatotoxicity in male mice

Chronic exposure to coplanar polychlorinated biphenyls（PCBs）,a potent inducer of toxic reactive oxygen species（ROS）,in the environment and food can cause liver diseases.It remains unknown whether caffeic acid derivatives（CADs） exerted protective effect on PCB-induced hepatotoxicity.We sought to evaluate the activities of 3CADs on PCB169-induced oxidative stress and DNA damage in the liver.Male ICR mice were administered with1 μmol/mL PCB169 at 5 mL/kg body weight for 2 weeks.The mice were given CADs by gastric gavage for 3weeks.We found that PCB169 decreased the growth rate and reduced the levels of superoxide dismutase（SOD）,glutathione（GSH） and GSH peroxidase（GPx）.It increased the liver weight,malondialdehyde（MDA）and 8-hydroxy-2＇-deoxyguanosine（8-OHdG） levels and CYPlAl activity in the liver tissues and plasma of mice（P〈0.05）.Pretreatment of mice with CADs restored the above parameters to normal levels.There was a synergistic protective effect between CADs in preventing MDA and 8-OHdG formation and inducing CYPlAl and phase II metabolism enzyme（SOD,GPx） activities（P〈0.05）.In conclusion,PCB169 induced hepatotoxicity and pretreatment with CADs had synergistic protective effects on liver damage.     

Gabapentin,a Synthetic Analogue of Gamma Aminobutyric Acid,Reverses Systemic Acute Inflammation and Oxidative Stress in Mice

The aim of this study was to investigate the potential anti-inflammatory and anti-oxidant effects of gabapentin (GBP) in mice. The anti-inflammatory and anti-oxidant effects were evaluated using various mediators that induce paw edema, peritonitis model, myeloperoxidase (MPO) activity, proinflammatory cytokine levels, glutathione (GSH) consumption, and malondialdehyde (MDA) production in mice. Pretreatment of mice with GBP (1 mg/kg) significantly reduced carrageenan or dextran-induced paw edema (P?2. In the carrageenan-induced peritonitis model, GBP significantly decreased total and differential leukocyte counts and reduced the levels of MPO activity in the plantar tissue and IL-1β and TNF-α concentrations in the peritoneal exudate. The same dose of GBP also decreased the MDA concentration and increased the levels of GSH into the peritoneal fluid. In summary, our results demonstrated that GBP exhibited anti-inflammatory activity in mice by reducing the action of inflammatory mediators, neutrophil migration and proinflammatory cytokine levels, and anti-oxidant properties by decreasing the concentration of MDA and increasing the GSH content. These observations raise the possibility that GBP could be used to improve tissue resistance to damage during inflammatory conditions.     

The hydrogen sulfide donor,Lawesson's reagent,prevents alendronate-induced gastric damage in rats

Our objective was to investigate the protective effect of Lawesson''s reagent, an H₂S donor, against alendronate (ALD)-induced gastric damage in rats. Rats were pretreated with saline or Lawesson''s reagent (3, 9, or 27 µmol/kg, po) once daily for 4 days. After 30 min, gastric damage was induced by ALD (30 mg/kg) administration by gavage. On the last day of treatment, the animals were killed 4 h after ALD administration. Gastric lesions were measured using a computer planimetry program, and gastric corpus pieces were assayed for malondialdehyde (MDA), glutathione (GSH), proinflammatory cytokines [tumor necrosis factor (TNF)-α and interleukin (IL)-1β], and myeloperoxidase (MPO). Other groups were pretreated with glibenclamide (5 mg/kg, ip) or with glibenclamide (5 mg/kg, ip)+diazoxide (3 mg/kg, ip). After 1 h, 27 µmol/kg Lawesson''s reagent was administered. After 30 min, 30 mg/kg ALD was administered. ALD caused gastric damage (63.35±9.8 mm²); increased levels of TNF-α, IL-1β, and MDA (2311±302.3 pg/mL, 901.9±106.2 pg/mL, 121.1±4.3 nmol/g, respectively); increased MPO activity (26.1±3.8 U/mg); and reduced GSH levels (180.3±21.9 µg/g). ALD also increased cystathionine-γ-lyase immunoreactivity in the gastric mucosa. Pretreatment with Lawesson''s reagent (27 µmol/kg) attenuated ALD-mediated gastric damage (15.77±5.3 mm²); reduced TNF-α, IL-1β, and MDA formation (1502±150.2 pg/mL, 632.3±43.4 pg/mL, 78.4±7.6 nmol/g, respectively); lowered MPO activity (11.7±2.8 U/mg); and increased the level of GSH in the gastric tissue (397.9±40.2 µg/g). Glibenclamide alone reversed the gastric protective effect of Lawesson''s reagent. However, glibenclamide plus diazoxide did not alter the effects of Lawesson''s reagent. Our results suggest that Lawesson''s reagent plays a protective role against ALD-induced gastric damage through mechanisms that depend at least in part on activation of ATP-sensitive potassium (K_ATP) channels.     

Anti-Ulcerogenic Activity of the Methanol Root Bark Extract of Cochlospermum Planchonii (Hook f)

Cochlospermum planchonii (Hook f) is a common medicinal plant used in Nigeria traditional medicine for treatment of different ailments including ulcers. The anti ulcer activity of the root bark methanol extract of Cochlospermum planchonii was evaluated using different [ethanol, acetylsalicylic acid (aspirin), cold/restraint stress and pyloric ligation/histamine - induced ulcers and acid production] ulcerogenic models in rats at the doses of 250, 500, and 1000 mg/kg body weight using cimetidine (100 mg/kg) as a standard reference drug. The different doses of the extract and the reference drug significantly (p < 0.01) decreased all the ulcer parameters in a dose dependent manner in all the models used. The total number of ulcers were significantly (p < 0.05) decreased. The ulcer index was significantly (p < 0.004) reduced by the extract. Similarly, the percentage ulcer preventive index was also increased from 0% in the negative control up to 93.2% at the dose of 1000 mg/kg, while the percentage ulcer severity was dose dependently reduced by the extract. Furthermore, the extract significantly (p < 0.02) decreased free gastric HCl and total gastric acid. In conclusion, Cochlospermum planchonii methanolic root bark extract showed significant antiulcer activity in this study which may be as a result of its cytoprotective, antioxidant or antisecretory properties.     

Protective effect of sildenafil citrate on contralateral testis injury after unilateral testicular torsion/detorsion

OBJECTIVES:

This study was designed to investigate prevention of contralateral testicular injury with sildenafil citrate after unilateral testicular torsion/detorsion.

METHODS:

Thirty‐seven adult male rats were divided into four groups: sham operated (group 1, n  =  7), torsion/detorsion + saline (group 2, n  =  10), torsion/detorsion + 0.7 mg of sildenafil citrate (group 3, n  =  10) and torsion/detorsion + 1.4 mg of sildenafil citrate (group 4, n  =  10). Unilateral testicular torsion was created by rotating the right testis 720° in a clockwise direction for 2 h in other groups, except for group 1, which was served as sham group. After torsion (2 h) and detorsion (2 h) periods, rats were killed.

RESULTS:

The level of reduced glutathion (GSH) (p<0.05) and the activities of catalase (p<0.01) and glutathione peroxidase (p<0.05) in the contralateral testis from group 2 were significantly lower and nitric oxide (NO) (p<0.05) level in the contralateral testis were significantly higher than those of group 1. Administration of low‐dose sildenafil citrate (group 3) prevented the increases in malondialdehyde and NO levels and decreases in glutathione peroxidase activities and GSH values induced by testicular torsion. However, administration of high‐dose sildenafil citrate (group 4) had no effect on these testicular parameters (p>0.05). Histopathological changes were detected in groups 2, 3 and 4.

CONCLUSION:

These results suggest that biochemically and histologically torsion/detorsion injury occurs in the contralateral testis following 2‐h torsion and 2‐h detorsion and that administration of low‐dose sildenafil citrate before detorsion prevents ischemia/reperfusion cellular damage in testicular tissue.     

Antiulcerogenic Activity of Ethanolic Leaf Extract of Lasianthera Africana

The effect of ethanolic leaf extract of Lasianthera africana on experimentally induced ulcer was studied in rats. The extract (1000 – 3000mg/kg) inhibited ethanol-induced, indomethacin - induced and reserpine -induced ulcer models in a dose dependent fashion. The various degrees of inhibitions were statistically significant (p<0.01). The effect of the extract was comparable to that of the standard drugs used. Thus, Lasianthera africana extract demonstrated a good antiulcer activity which supports the antiulcer effect of this plant in traditional medicine.     

Oxidative stress and cellular immunity in patients with recurrent aphthous ulcers

Recurrent aphthous ulcer (RAU) is an inflammatory condition of the oral mucosa characterized by painful, well-circumscribed, single or multiple round or ovoid ulcerations. The exact etiologic factor(s) of these ulcerations are not yet understood. The objective of this study was to evaluate inflammatory processes and free radical metabolism of 25 patients with RAUs compared to 25 healthy controls. The levels of malondialdehyde (MDA) and glutathione (GSH) were determined by high-performance liquid chromatography. Tumor necrosis factor-alpha (TNF-α), interleukin-2 (IL-2), IL-10, and IL-12 were determined by ELISA. Nitric oxide (NO), myeloperoxidase (MPO), total antioxidant status (TAS), and total oxidant status (TOS) levels were measured spectroscopically in serum. The levels of MDA, GSH, TNF-α, IL-2, IL-12, MPO, and TOS, and oxidative stress index (OSI) were higher, and the levels of NO, IL-10, and TAS were lower in patients with RAU than in controls. Statistical analysis showed that GSH, TNF-α, IL-2, IL-10, and OSI differed significantly in patients with RAU compared to controls. These parameters have important roles in oxidant/antioxidant defense.     

阿魏酸钠对结肠炎大鼠结肠巨噬细胞功能的影响

目的:探讨阿魏酸钠在整体水平下对结肠炎大鼠结肠巨噬细胞功能的影响及其机制。方法:建立大鼠免疫性结肠炎模型。阿魏酸钠(SF)灌肠用药21d后检测结肠组织MDA、NO、PGE₂含量,SOD、IL-1、TNF-α、MPO活性及NF-κBp65表达水平。结果:阿魏酸钠(200、400、800mg/kg)灌肠用药剂量依赖性降低模型组大鼠显著升高的MDA、NO、PGE₂含量,IL-1、TNF-α、MPO活性及NF-κBp65表达水平,同时升高显著降低的SOD活性。结论:SF整体水平下减弱结肠炎大鼠结肠活化巨噬细胞的生物活性,缓解结肠炎症反应,机制可能与抑制NF-κB表达有关。     

In Vitro Antioxidant and In Vivo Hepatoprotective Activity of Leave Extract of Raphanus Sativus in Rats Using CCL4 Model

Background

Raphanus sativus is reported to have a variety of biological activities. This work screened the hepato-protective and antioxidant activity of ethanol (ERS), and aqueous (ARS), extracts of leaves of Raphanus sativus in Carbon tetrachloride (CCl₄), model in rats.

Material and Methods

The extracts were subjected to antioxidant tests (Total reducing power and Total phenolic content), and preliminary phytochemical screening. A pilot study was done on 100 and 300 mg/kg extracts, form which 300 mg was chosen for further experiments. The albino rats (200–250 grams), were divided into 5 groups of 6 animals each (n=6). There were three control groups comprising of normal control (normal saline −1ml/kg), negative control group (CCl₄ 1ml/kg in olive oil in a ratio of 1:1 v/v), and positive control group (Silymarin 50mg/kg). The Test drugs were given in a dose of 300 mg/kg for both ERS and ARS extract for 7 days. Biochemical parameters (AST, ALT, Alkaline phosphatase, Total Bilirubin), histo-pathological examination of liver and in vivo antioxidant tests [CAT, GSH and MDA] were done.

Results

The phytochemical study showed the presence of flavanoids, terpenoids, alkaloids, saponins and sterols. A dose dependent increase in the oxidative potential was observed in both the extracts with total phenolic content 70.1 and 44.4 GAE/g extract for ERS and ARS respectively. ERS 300mg/kg showed a significant (p<0.001) increase in levels of AST, ALT and alkaline phosphatase as compared to negative control (percentage hepatoprotection =45.3%) while ARS 300 mg/kg (p<.01) group showed 30% hepatoprotection. The GSH (p<0.001) and CAT (p<0.05) in ERS and ARS were significantly increased while MDA levels were decreased (P< 0.01), as compared negative control. The findings were confirmed histo-pathological examination.

Conclusion

The ethanol and aqueous extract of Raphanus sativus have partial hepatoprotection against CCl₄ toxicity.     

Protective Effect of Quercetin on the Morphology of Pancreatic ��-Cells of Streptozotocin-Treated Diabetic Rats

This study was undertaken to investigate the protective effects of quercetin (QCT) on the morphology of pancreatic β-cells against diabetes mellitus and oxidative stress experimentally-induced by streptozotocin (STZ) treatment in Wistar rats. Fifty male and female Wistar rats (200–250 g) were randomly divided into three experimental groups (i. e., control, STZ-treated, and STZ + Quercetin-treated groups). Diabetes was induced in the diabetic groups (B and C) of animals, by a single intraperitoneal injection of STZ (75 mg/kg), while each of the rats in the ‘control’ group received equal volume of citrate buffer (pH 6.3) solution intraperitoneally. In group C rats, quercetin (QCT, 25 mg/kg/day i. p.) was injected daily for 3 days prior to STZ treatment, and QCT administration continued until the end of the study period (30 days). Diabetes mellitus was confirmed by using Bayer''s Glucometer Elite® and compatible blood glucose test strips. The rats were sacrificed serially until the end of the study period (after 30 days). The pancreases of the sacrificed rats were excised and randomly processed for histological staining and biochemical assays for antioxidant enzymes [such as glutathione peroxidase (GSHPx), superoxide dismutase (SOD), catalase (CAT), malondialdehyde (MDA) and serum nitric oxide (NO)]. In the diabetic state, pancreatic β-cells of STZ-treated group B rats histologically demonstrated an early chromatin aggregation, cytoplasmic vesiculation in the central β-cells, nuclear shrinkage, and lysis of β-cells with distortion of granules. The morphology of QCT-treated rats'' pancreases showed viable cellularity with distinct β-cell mass. STZ treatment significantly decreased (p<0.05) GSHPx, SOD, CAT and pancreatic insulin content. However, STZ treatment increased blood glucose concentrations, MDA and serum NO. The QCT-treated group of animals showed a significant decrease (p<0.05) in elevated blood glucose, MDA and NO. Furthermore, QCT treatment significantly increased (p<0.05) antioxidant enzymes'' activities, as well as pancreatic insulin contents. Quercetin (QCT) treatment protected and preserved pancreatic β-cell architecture and integrity. In conclusion, the findings of the present experimental animal study indicate that QCT treatment has beneficial effects on pancreatic tissues subjected to STZ-induced oxidative stress by directly quenching lipid peroxides and indirectly enhancing production of endogenous antioxidants.     

Glutathione S-Transferase P1 Correlated with Oxidative Stress in Hepatocellular Carcinoma

Background: Glutathione-S-transferase P1 (GSTP1) is an important phase II enzyme that can protect cells from oxidative stress in various human cancers. However, few clinical studies were undertaken on the relationship between GSTP1 and oxidative stress in hepatocellular carcinoma (HCC). The present study was therefore aimed to evaluate the potential associations between GSTP1 and oxidative stress in HCC patients.Methods: The GSTP1 expression in peripheral blood mononuclear cells (PBMCs) was determined by flow cytometry from 38 HCC patients and 38 chronic hepatitis B (CHB) patients. The GSTP1 mRNA level in PBMCs was determined by real-time quantitative polymerase chain reaction. Enzyme-linked-immunosorbent-assay (ELISA) was performed to measure the oxidative stress status, including plasma levels of malondialdehyde (MDA), xanthine oxidase (XOD), reduced glutathione hormone (GSH) and glutathione-S-transferases (GST).Results: Significantly decreased GSTP1 protein expression was found in HCC patients than in CHB patients (P<0.05). The GSTP1 mRNA expression of HCC patients was also decreased compared with CHB patients (P<0.05). MDA and XOD levels were significantly higher in HCC patients than in CHB patients, while plasma GSH and GST levels were statistically lower in HCC patients than in CHB patients. GSTP1 expression level was correlated with plasma levels of MDA (P<0.01), XOD (P = 0.01) and GSH (P< 0.01), GST (P< 0.01).Conclusion: We demonstrated that the reduced GSTP1 expression might contribute to oxidative stress in the development of HCC from CHB.     

Effect of Methylsulfonylmethane on Paraquat-Induced Acute Lung and Liver Injury in Mice

Methylsulfonylmethane (MSM) is a natural organosulfur compound that exhibits antioxidative and anti-inflammatory effects. This study was carried out to investigate the effect of MSM on paraquat (PQ)-induced acute lung and liver injury in mice. A single dose of PQ (50 mg/kg, i.p.) induced acute lung and liver toxicity. Mice were treated with MSM (500 mg/kg/day, i.p.) for 5 days. At the end of the experiment, animals were euthanized, and lung and liver tissues were collected for histological and biochemical analysis. Tissue samples were used to determine malondialdehyde (MDA), myeloperoxidase (MPO), catalase (CAT), superoxide dismutase (SOD), glutathione (GSH), and tumor necrosis factor-α (TNF-α) levels. Blood samples were used to measure plasma alanine transaminase (ALT), γ-glutamyl transferase (GGT), and alkaline phosphatase (ALP). Histological examination indicated that MSM decreased lung and liver damage caused by PQ. Biochemical results showed that MSM treatment significantly reduced tissue levels of MDA, MPO, and TNF-α, while increased the levels of SOD, CAT, and GSH compared with PQ group. MSM treatment also significantly reduced plasma levels of ALT, GGT, and ALP. These findings suggest that MSM as a natural product attenuates PQ-induced pulmonary and hepatic oxidative injury.     

Nebivolol prevents indomethacin-induced gastric ulcer in rats

Gastric ulcer is a very common gastrointestinal disease that may lead to dangerous complications and even death. This study was conducted to evaluate the prophylactic effect of nebivolol against indomethacin [INDO]-induced gastric ulcer. Male Wistar rats were divided into four groups: normal control, ulcer control (INDO only), omeprazole before INDO and nebivolol before INDO. Each rat to receive nebivolol and omeprazole was given the agent orally (by gavage) daily for 10 days prior to induction of ulcer by oral dosing with INDO. Four hours after INDO treatment, all rats were euthanized and their stomachs obtained for measures of gastric acidity, oxidative stress and inflammatory markers, as well as cytoprotective mediators. The results showed that a single oral dose of INDO (100?mg/kg) induced gastric acidity, an ulcer index of 2900 and significantly increased levels of gastric tumor necrosis factor (TNF)-α and malondialdehyde (MDA) and significantly decreased levels of gastric prostaglandin E₂ (PGE₂), glutathione (GSH) and nitric oxide (NO), compared to in normal control counterpart stomachs. Giving nebivolol before INDO corrected the gastric acidity and resulted in a significant increase in GSH, PGE₂ and NO and a significant decrease in TNFα and MDA gastric levels, compared to ulcer control values. Results obtained with nebivolol were comparable to those with omeprazole; the preventive index in the nebivolol group was 90.7% compared to 94.5% in rats in the omeprazole group. These studies showed that nebivolol provided a valuable role in preventing gastric ulcers induced by INDO and provided a promise for potentially protecting hypertensive patients from experiencing gastric ulcer. Thus, it is possible that, pending further studies, nebivolol could be used for pre-exposure prophylaxis from gastric ulcer in these patients.     

Inhibition of Radiation-Induced Oxidative Damage in the Lung Tissue: May Acetylsalicylic Acid Have a Positive Role?

The lung is relatively sensitive to irradiation. It is shown that acetylsalicylic acid (ASA) might reduce oxidative injury and that it has a place in protection from cancer. The aim of this study is to evaluate the potential radioprotective effects of ASA. Whole-body irradiation (6 Gy, single dose) was applied to the rats. Glutathione (GSH), malondialdehyde (MDA), myeloperoxidase (MPO), and nitric oxide (NO) levels in the lung tissue were measured. Control (C), Radiation (R), Radiation?+?ASA (R?+?ASA; received irradiation and 25 mg/kg of ASA intraperitoneally (i.p.)), and Radiation?+?Amifostine (R?+?WR-2721; received irradiation and 200 mg/kg of WR-2721 i.p.) groups were used. The MPO levels decreased statistically significantly in the group administered ASA. Histopathologically, a radioprotective effect of ASA was more evident in the R?+?ASA group. ASA is an agent which has not been used as a radioprotector in the clinic yet, and it is worth supporting with more advanced studies.     

Protective Effect of Infliximab,a Tumor Necrosis Factor-Alfa Inhibitor,on Bleomycin-Induced Lung Fibrosis in Rats

We aimed to investigate the preventive effect of Infliximab (IFX), a tumor necrosis factor (TNF)-α inhibitor, on bleomycin (BLC)-induced lung fibrosis in rats. Rats were assigned into four groups as follows: I—BLC group, a single intra-tracheal BLC (2.5 mg/kg) was installed; II—control group, a single intra-tracheal saline was installed; III—IFX?+?BLC group, a single-dose IFX (7 mg/kg) was administered intraperitoneally (i.p.), 72 h before the intra-tracheal BLC installation; IV—IFX group, IFX (7 mg/kg) was administered alone i.p. on the same day with IFX?+?BLC group. All animals were sacrificed on the 14th day of BLC installation. Levels of tumor necrosis factor (TNF)-α, transforming growth factor (TGF)-β, interleukin (IL)-6, periostin, YKL-40, nitric oxide (NO) in rat serum were measured, as well as, myeloperoxidase (MPO), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) activity, and reduced glutathione (GSH), hydroxyproline, malondialdehyde (MDA) content in lung homogenates. Lung tissues were stained with hematoxylin and eosin (H&E) for quantitative histological evaluation. The inducible nitric oxide synthase (iNOS) expression and cell apoptosis in the lung tissues were determined quantitatively by immunohistochemical staining (INOS) and by TUNNEL staining, respectively. BLC installation worsened antioxidant status (such as SOD, CAT, GPx, GSH, MPO), while it increased the serum TNF-α, TGF-β, IL-6, periostin, YKL-40, and lipid peroxidation, and collagen deposition, measured by MDA and hydroxyproline, respectively. IFX pretreatment improved antioxidant status as well as BLC-induced lung pathological changes, while it decreased the TNF-α, TGF-β, IL-6, periostin, YKL-40, lipid peroxidation and collagen deposition. Finally, histological, immunohistochemical, and TUNNEL evidence also supported the ability of IFX to prevent BLC-induced lung fibrosis. The results of the present study indicate that IFX pretreatment can attenuate BLC-induced pulmonary fibrosis.     

Effects of Ginkgo Biloba Extract on Free Radical Metabolism of Liver in Mice During Endurance Exercise

This study investigated the effect of Ginkgo biloba extract on Free Radical Metabolism of Liver in mice during endurance exercise. Forty-eight mice were divided into the quiet group and the exercised group. And the two groups were both grouped again, including the control group and the drug-treated group. After exhaustive exercise, the exercised groups were subdivided into the immediate group and the recovery group. The swimming time to exhaustion significantly prolonged in the exercised drug-treated group as compared with the exercised control group (P <0.05); The SOD activity of drug-treated groups significantly increased (P <0.05) as compared with the control groups and MDA content was significantly lower (P <0.05). The SOD activity and MDA content of exercised control groups significantly increased (P <0.05) as compared with the quiet control group. The SOD activity and MDA content of exercised drug-treated groups significantly increased (P <0.05) as compared with the quiet drug-treated group. The results indicated that Ginkgo biloba extract can obviously increase the body''s endurance exercise capacity in mice and delay fatigue; Ginkgo biloba extract can help to increase the activity of the antioxidant enzymes in liver tissue, reduce the lipid peroxidation injury in liver tissue caused by free radicals, improve athletic ability, and promote the recovery process after exercise in mice.     

Pathophysiological role of nitric oxide in rat experimental colitis

Overproduction of nitric oxide (NO) by inducible nitric oxide synthase (iNOS) may contribute to the pathophysiology of ulcerative colitis. A 2,4,6-trinitrobenzenesulfonic acid sodium salt (TNBS) colitis model was established to examine the effect of selective iNOS inhibition, by S-(2-aminoethyl) isothiouronium bromide (ITU), on colonic mucosal cell damage and inflammation. Rats, killed 7 days after TNBS, had increased colonic mucosal levels of iNOS and interleukin-8 (IL-8), in addition to severe colonic inflammation which was characterized by significantly increased colon weight, damage score and colonic myeloperoxidase activity (MPO) (a marker of neutrophil influx). TNBS-treated rats had markedly decreased body weight and thymus weight. Administration of colitic rats with ITU significantly inhibited iNOS activity/expression and tended to reduce mucosal levels of IL-8, but no effect on MPO activity was observed. Following ITU therapy, colitic rats had reduced colonic damage and losses in body weight and thymus weight were reversed. Improvement of TNBS colitis by ITU suggested that excess NO, produced by iNOS, may have contributed to the initiation/ amplification of colonic disease, by mechanisms including enhancement of IL-8 releaseNO-mediated enhancement of pro-inflammatory cytokine release was further investigated in vitro. Lipopolysaccharide (LPS) and interferon-γ (IFN-γ) stimulated release of nitrite, lactate dehydrogenase (LDH), TNFα, IL-1β and IL-8 from rat peritoneal macrophages, all of which were significantly reduced by ITU. This suggests that NO-mediated cell damage enhances pro-inflammatory mediator release from macrophages. In addition, enhancement of IL-8 and TNFα release was also partially NO-dependent in activated peritoneal neutrophils. Therefore, the amelioration of TNBS colitis by ITU could include inhibition of NO-mediated pro-inflammatory cytokine release.     

Effect of taurine on oxidative stress and apoptosis-related protein expression in trinitrobenzene sulphonic acid-induced colitis

Ulcerative colitis (UC) is a multi-factorial inflammatory disease of the colon and rectum. The present study was undertaken to investigate the effect of taurine, an anti-oxidant amino acid, on oxidative stress and the expression of apoptosis-related proteins, pro-apoptotic Bax and anti-apoptotic B cell lymphoma-2 (Bcl-2) in colon tissue in rats with 2,4,6-trinitrobenzene sulphonic acid (TNBS)-induced colitis. Rats received taurine (1.5% w/v) in drinking water for 15 days before and 15 days after administration of TNBS solution. Then, colonic myeloperoxidase (MPO) activity, malondialdehyde (MDA) and glutathione (GSH) levels, and Bax and Bcl-2 expression were measured. TNBS-induced colitis caused significantly increased MPO activity and MDA levels and decreased GSH levels in colon tissue compared to controls. Increase in Bax expression and decrease in Bcl-2 expression were detected in colon of rats with TNBS-induced colitis. Taurine treatment was associated with amelioration in macroscopic and microscopic colitis scores, decreased colonic MPO activity and MDA levels and increased GSH levels in TNBS-induced colitis. In addition, taurine reduced the expression of Bax and prevented the loss of Bcl-2 proteins in colon tissue of rats with TNBS-induced colitis. The results of this study show that taurine administration may exert beneficial effects in UC by decreasing inflammatory reactions, oxidative stress and apoptosis.     

Estradiol Treatment Ameliorates Acetic Acid-Induced Gastric and Colonic Injuries in Rats

To evaluate the role of estrogen treatment on the healing of acetic acid-induced gastric or colonic injury, rats were given 17beta estradiol benzoate (0.001, 0.1, and 10 mg/kg) or vehicle for 7 days (following the induction of ulcer) or 4 days (following the induction of colitis) until they were decapitated. Food intake and fecal output were decreased by estradiol treatment but gastric emptying rate was not changed. Estradiol (10 mg/kg) reduced gastric ulcer index and colonic damage score compared to vehicle-treated groups. SEM and light microscopy demonstrated a significant reduction in the severity of ulcers and colitis by estradiol treatment. Gastric microscopic score was not changed by estradiol treatment, whereas in the colonic tissue score was significantly reduced. Elevated gastric MPO levels were reduced in gastric but not in colonic tissues as compared with corresponding vehicle groups. In conclusion, exogenous estradiol treatment at pharmacological doses improves the healing of both gastric and colonic injury induced by acetic acid in rats.