Effects of statins in an indomethacin-induced gastric injury model in rats.

BACKGROUND/AIMS: Statins have additional pleiotropic effects beyond their lipid-lowering effects. In this study, the effects of statins were evaluated in an indomethacin-induced gastric injury model in rats. MATERIALS AND METHODS: Animals were divided into eight groups. Distilled water (control group), omeprazole (30 mg/kg), atorvastatin (20 and 40 mg/kg), simvastatin (20 and 40 mg/kg), and rosuvastatin (20 and 40 mg/kg) were given orally (gavage). Thirty minutes later, indomethacin (25 mg/kg) was administered orally to all groups. Six hours later, the animals were sacrificed by decapitation. The mean ulcer indexes for each group were calculated, and the stomachs were evaluated histopathologically. RESULTS: The ulcer indexes were as follows: control 1.72 ± 0.16, omeprazole 0 ± 0.00, and atorvastatin, simvastatin and rosuvastatin (at 20 and 40 mg/kg doses, respectively) 4.28 ± 0.39, 4.99 ± 0.96, 1.72 ± 0.73, 1.90 ± 0.48, 1.85 ± 0.26, and 1.67 ± 0.18. Atorvastatin significantly increased the indomethacin-induced ulcer index at both doses and the erosion score at 40 mg/kg dose. Although the 20 mg/kg dose of simvastatin inhibited mononuclear leukocyte infiltration, the 40 mg/kg dose induced hyperemia. Rosuvastatin did not decrease mononuclear leukocyte or neutrophil infiltrations at 20 mg/kg dose, and only neutrophil infiltration at the 40 mg/kg dose. CONCLUSIONS: In patients with gastric discomfort, statins must be used carefully. If statin therapy is needed, we recommend to avoid using atorvastatin and to use the other statins only in the minimum effective dose.

Role of angiotensin and endothelin in testicular ischemia reperfusion injury.

OBJECTIVES: To determine whether angiotensin and endothelin have any role in testicular ischemia reperfusion injury by investigating the effects of the angiotensin converting enzyme inhibitor enalapril, selective non-peptide angiotensin-II type I blocker losartan and dual endothelin receptor blocker bosentan. METHODS: Rats were anesthetized with thiopental sodium (50 mg/kg i.p.) before the operation. The left testicular artery and vein of rats were occluded for 1 h; before the bilateral orchiectomy, the organ was allowed to reperfuse for 3 h or 24 h. Enalapril (20 mg/kg i.p.), losartan (30 mg/kg i.p.), bosentan (10 mg/kg i.p.) or vehicle (saline) were given 30 min before reperfusion. Malondialdehyde level was measured in testicular tissue after 3 h of reperfusion. Histological examination was carried out after 24 h of reperfusion. RESULTS: Ischemia reperfusion caused a significant increase in malondialdehyde level of ipsilateral testis, and histopathological injury in both ipsilateral and contralateral testes. Enalapril, losartan and bosentan treatments prevented the ischemia reperfusion-induced augmentation in malondialdehyde levels. Only bosentan treatment ameloriated ischemia reperfusion-induced histopathological alterations. CONCLUSIONS: Endothelin might play a more important role in pathogenesis of testicular ischemia reperfusion injury when compared with angiotensin.

Effects of 3-aminobenzamide on unilateral testicular ischemia-reperfusion injury: what is the role of PARP inhibition?

The therapeutic effects of poly(adenosine diphosphate-ribose) polymerase inhibition by 3-aminobenzamide (3-AB) were investigated in testicular ischemia-reperfusion (I/R) injury, using sperm analysis and histopathological and biochemical examinations, including superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) activities and reduced glutathione (GSH) levels. Male rats were divided into 3 groups: sham (n = 12), I/R (n = 12), and I/R with 3-AB (I/R-3-AB) (n = 12). The left testicular artery was occluded for 1 h, followed by 24 h (for biochemical and histopathological examinations) and 30 days (for sperm analysis) of reperfusion. 3-AB treatment intraperitoneally 10 min prior to and 1 h after reperfusion increased the I/R-induced decrease in sperm motility in both testes and reduced the increased abnormal sperm rates in the ipsilateral testis. However, 3-AB treatment failed to prevent the I/R-induced decrease in sperm concentration in both testes. SOD and CAT activities did not change in any group. GSH-Px activity and GSH levels were increased by I/R. 3-AB treatment reversed the I/R-induced increase in GSH-Px activity, similar to the level in sham rats, but did not alter GSH levels. 3-AB treatment significantly increased the I/R-induced decrease in histopathologic score. In conclusion, 3-AB treatment has potential biochemical and histopathological benefits beyond improving sperm quality and may have the potential to decrease damage from testicular torsion.

Effect of lycopene on caspase-3 enzyme activation in liver of methanol-intoxicated rats: comparison with fomepizole.

Lycopene is one of the major carotenoids and is found almost exclusively in tomatoes and tomato products. This study was performed to evaluate the effect of lycopene on methanol-induced liver injury and to compare the results with those after fomepizole, which is used in treatment of methanol intoxication. Experiments were carried out with 30 female Wistar rats weighting 180-200 g. Rats were injected with a intraperitoneally dose of 3 g/kg methanol as a 50% solution in isotonic saline once for intoxication. Rats were pretreated with fomepizole (50 mg/kg) and/or lycopene (10 mg/kg) before methanol. After 24 hours all the drug-treated and intoxicated rats were sacrificed under anesthesia. Malondialdehyde (MDA) levels were determined in order to assess lipid peroxidation, and caspase-3 activity was determined by immunostaining of liver tissues to evaluate apoptosis. Methanol administration significantly increased the MDA level and caspase-3 activity in liver. Pretreatment with lycopene and/or fomepizole decreased the MDA levels significantly. Similarly, lycopene and fomepizole decreased methanol-induced caspase-3 activity. The findings of the present study demonstrate that methanol intoxication causes hepatic toxicity in rats and that this is likely a result of reactive oxygen species and apoptosis induction. Lycopene has protective effects against methanol-induced hepatic injury similar to fomepizole. It was demonstrated for the first time that both lycopene and fomepizole prevent methanol-induced hepatic injury by reducing the increase of lipid oxidation and caspase-3 activation.

Effects of increasing ratio of progesterone in estrogen/progesterone combination on total oxidant/antioxidant status in rat uterus and plasma.

PURPOSE: The relationship between increasing ratio of progesterone in estrogen/progesterone combination and oxidative stress (OS) was investigated. METHODS: Thirty non-pregnant Wistar Albino female rats were divided into five groups and bilaterally ovariectomized (Ovx) except sham group. GROUPS: Sham + 0.3 cc seaseme oil, Ovx + 0.3 cc seaseme oil, Ovx + estradiol propionate (E2) (1 µg/kg), Ovx + E2 + medroxyprogesterone acetate (MPA) 1 mg/kg, Ovx + E2 + MPA 20 mg/kg. Hormones were applied for three consecutive days after 28 days of ovariectomy. Their uteri and blood samples were collected and nitric oxide (NO), malondialdehyde (MDA), total oxidative status (TOS) and total antioxidant capacity (TAC) levels were determined. RESULTS: E2 + MPA1 treatment decreased NO, MDA and TOS levels and increased TAC levels in uterus. Plasma NO levels elevated in all groups and MDA production increased due to E2 treatment when compared to ovariectomy. E2 + MPA20 treatment increased TOS levels, while TAC levels decreased when compared to ovariectomy in plasma. CONCLUSIONS: Using E2 plus low dose progesterone may prevent pathologies resourced of OS.

Effect of melatonin on epididymal sperm quality after testicular ischemia/reperfusion in rats.

OBJECTIVE: To determine the effect of melatonin, a pineal secretory product that prevents testicular ischemia/reperfusion (IR) injury through its antioxidative properties, on epididymal sperm quality in a rat testicular IR injury model. DESIGN: Experimental study. SETTING: University pharmacology laboratory. ANIMAL(S): Fifty-six 8-week-old male Wistar albino rats. INTERVENTION(S): Left testicular artery and vein occluded for 1 hour; before the bilateral orchiectomy, the organ was allowed to reperfuse 30 days. Melatonin (10 mg/kg IP) or vehicle (1% ethanol in saline) was administrated for 10 minutes before reperfusion and for 1 hour after reperfusion. MAIN OUTCOME MEASURE(S): After 24 hours of reperfusion, the rats were decapitated, and the testicular tissue samples were obtained for histologic examination. In addition, after 30 days of reperfusion, the epididymal sperm concentration, motility, and abnormal sperm rates were determined in the sperm collected from the epididymis. RESULT(S): A statistically significant decrease in sperm concentration resulted from IR as well as an increase in sperm abnormalities, but the sperm motility did not change. Melatonin treatment did not prevent the IR-induced reduction in sperm concentration. However, melatonin treatment statistically significantly decreased the sperm abnormalities when compared with the IR injured samples. CONCLUSION(S): Melatonin may improve sperm morphology for a protective effect in IR-induced testicular injury.

Lycopene, an antioxidant carotenoid, attenuates testicular injury caused by ischemia/reperfusion in rats.

Testicular torsion is a common syndrome that could lead to infertility. We investigated the therapeutic effects of lycopene, an antioxidant caretenoid, on testicular ischemia/reperfusion (IR) injury that resembles testicular torsion. Male Wistar albino rats were divided into three groups: sham (n = 6), IR (n = 18), and ischemia/reperfusion with lycopene (IRL, n = 18). Left testicular artery and vein was occluded for 1 h, followed by reperfusion of 3 h, 24 h or 30 days in IR and IRL animals. Either corn oil (vehicle) or lycopene (4 mg/kg) was administrated once daily by gavage to IR or IRL animals, respectively, 5 min after ischemia. Sham-operated animals were treated with vehicle by gavage 5 min after the operation. IR decreased sperm motility and concentration in both ipsilateral and contralateral testes and increased abnormal sperm rate in ipsilateral testis after 30 days of reperfusion. Treatment with lycopene increased the motility in bilateral testes and decreased the rate of abnormal sperm in ipsilateral testis to the sham level, but did not increase sperm concentration in bilateral testes. IR increased the activities of catalase and glutathione peroxidase and the level of reduced glutathione by 24 h of reperfusion, but malondialdehyde remained unchanged. Lycopene treatment restored the enzyme activities but not the reduced glutathione level. Lycopene treatment also ameliorated the IR-induced tissue damage in bilateral testes. In conclusion, the therapeutic antioxidant effect of lycopene on germ cells could serve as a promising intervention to oxidative stress-associated infertility problems, such as testicular torsion.

Melatonin treatment against remote organ injury induced by renal ischemia reperfusion injury in diabetes mellitus.

Oxidative stress may have a role in liver damage after acute renal injury due to various reasons such as ischemia reperfusion (IR). Diabetes mellitus (DM) is an important disease for kidneys and may cause nephropathy as a long term complication. The aim of this study was to investigate protective effect of melatonin, a potent antioxidant, against distant organ injury on liver induced by renal IR in rats with or without DM. The rats were divided into six groups: control (n=7), DM (n=5), IR (n=7), DM+IR (n=7), melatonin+IR (Mel+IR) (melatonin, 4 mg/ kg during 15 days) (n=7), and Mel+DM+IR groups (n=7). Diabetes developed 3 days after single i.p. dose of 45 mg/kg streptozotocin. After 15 day, the left renal artery was occluded for 30 min followed 24 h of reperfusion in IR performed groups. DM did not alter oxidative parameters alone in liver tissue. The levels of malondialdehyde, protein carbonyl and nitric oxide with activities of xanthine oxidase and myeloperoxidase were increased in liver tissues of diabetic and non-diabetic IR groups. Nitric oxide level in DM was higher than control. The activities of catalase and superoxide dismutase were increased in IR groups in comparison with control and DM. ALT and AST levels were higher in IR and DM+IR groups than control and DM. Melatonin treatment reversed all these oxidant and antioxidant parameters to control values as well as serum liver enzymes. We concluded that renal IR may affect distant organs such as liver and oxidative stress may play role on this injury, but DM has not an effect on kidney induced distant organ injury via oxidant stress. Also, it was concluded that melatonin treatment may prevent liver oxidant stress induced by distant injury of kidney IR.

Effect of melatonin on testicular ischemia/reperfusion injury in rats: is this effect related to the proinflammatory cytokines?

OBJECTIVE: To determine whether the protective effect of melatonin in testicular ischemia/reperfusion (IR) injury is mediated by the proinflammatory molecules. DESIGN: Experimental study. SETTING: University pharmacology laboratory. ANIMAL(S): Fifty-six 8-week-old male Wistar albino rats. INTERVENTION(S): Left testicular artery and vein was occluded for 1 hour, followed by 3 hours or 24 hours of reperfusion. Melatonin (10 mg/kg IP) or vehicle (1% ethanol in saline) was given 10 minutes before ischemia. MAIN OUTCOME MEASURE(S): Malondialdehyde (MDA), protein carbonyl (PC) content, myeloperoxidase (MPO) activity, and proinflammatory cytokines TNF-alpha, IL-1beta, and IL-6 were examined in testicular tissue after 3 hours of reperfusion. Histologic examination was made after 24 hours of reperfusion. RESULT(S): The MDA, PC, and MPO levels in testicular tissue increased significantly after IR, but the proinflammatory cytokine levels did not change. Melatonin treatment decreased lipid and protein oxidation and ameloriated histopathologic alterations induced by IR without any change in proinflammatory cytokine levels. CONCLUSION(S): The protective effect of melatonin on IR-induced testiculary injury is related to its antioxidant properties but not to proinflammatory cytokines.

Melatonin improves methanol intoxication-induced oxidative liver injury in rats.

This study was performed to evaluate the effect of melatonin on methanol-induced liver injury. We evaluated the levels of malondialdehyde (MDA), protein carbonylation (PC), myeloperoxidase (MPO) activities and to assess lipid peroxidation, protein oxidation, neutrophil accumulation and nitrite which is a stable end product of nitric oxide respectively. We also studied superoxide dismutase, catalase, and glutathione peroxidase activities of liver tissue to evaluate the changes in the antioxidant status. Histopathological alterations were also determined. The experiment was performed on Wistar rats, which received intragastric 3 g/kg methanol as a 50% solution in isotonic saline once. After 6 and 24 hr all the drug received and intoxicated rats were killed under anesthesia. Pretreatment with melatonin (10 mg/kg) decreased the MDA levels significantly, restored the PC levels to the control, prevented the increase of nitrite level and MPO activity significantly and reversed to the control levels, prevented the reduction in all of the antioxidant enzyme activities. Additionally in melatonin treated group piecemeal necrosis, lobular lytic necrosis, and portal inflammation returned to normal histologic appearances when compared with methanol administration. In conclusion, melatonin has protective effects against methanol-induced hepatic injury.

Melatonin protects from ischemia/reperfusion-induced renal injury in rats: this effect is not mediated by proinflammatory cytokines.

The pathophysiologic mechanisms leading to acute ischemic renal failure are not completely understood. Melatonin, a compound with well-known antioxidant properties, reduces IR-induced renal injury. The purpose of the present study was to investigate the changes in levels of tumor necrosis factor (TNF)-alpha, IL-beta, and IL-6 in postischemic reperfused renal tissue, and to determine whether the protective effect of melatonin is related the modulation of the production of these inflammatory molecules. Male Wistar albino rats were unilaterally nephrectomized and subjected to 1 hr of renal pedicle occlusion followed by 2 hr or 24 hr of reperfusion. Melatonin (10 mg/kg, i.p.) or vehicle was administrated at 10 min prior to ischemia. After 24 hr of the reperfusion, following decapitation, kidney samples were taken both for histologic examination and for the determination of malondialdehyde (MDA), myeloperoxidase (MPO) activity, total antioxidant capacity (TAC), total oxidative stress (TOS), creatinine, and blood urea nitrogen (BUN). These were measured in serum samples. TNF-alpha, IL-beta, and IL-6 were measured in kidney samples after 2 hr of reperfusion. IR caused a significant increase in renal MDA, MPO, TOS, creatinine, and BUN while decrease TAC without any change in TNF-alpha, IL-beta, and IL-6 levels. Melatonin treatment reduced the biochemical indices without any change in the cytokine levels and ameliorated histopathologic alterations induced by IR. The protective effect of melatonin on IR-induced renal injury is related to its antioxidant properties but not to proinflammatory cytokines.

Nasal polyp diseases in allergic and nonallergic patients and steroid therapy.

OBJECTIVE: To investigate widespread disease causes, cellular-structural differences, and steroid response of nasal polyps (NPs). METHOD: Study group consisted of NPs, allergic-NPs, NPs with steroid therapy (ST), antrochoanal polyp (ACP), and controls. We investigated stromal eosinophil, mast cell, CD4+ and CD8+ cell counts and presence of squamous metaplasia, Ki-67 expression, intraepithelial eosinophils-mast cells, epithelial damage, edema, fibrosis, hyalinization, polymorphonuclear leukocyte, and glandular hyperplasia. RESULTS: In allergic-NPs, intraepithelial eosinophils and epithelial damage CD4+ were significantly higher than NPs and also, eosinophils, mast cells, intraepithelial eosinophils, and epithelial damage were significantly higher than ACP. Only stromal eosinophilic infiltration was significantly higher in NPs than ACP. There was significant increased glandular hyperplasia and decreased intraepithelial eosinophils, mast cells, CD4+ cells, squamous metaplasia, and epithelial damage with ST in allergic-NPs. There were no significant differences with ST in NPs. CONCLUSION: NPs in allergic and nonallergic patients may differ in their histology and in their histologic responses to ST. EBM RATING: B-3b.

Vascular reactivity to various vasoconstrictor agents and endothelium-dependent relaxations of rat thoracic aorta in the long-term period of pinealectomy.

In this study, the effects of reduced melatonin concentrations in the long-term period of pinealectomy on mean arterial blood pressure (BP) and vascular responses in isolated rat thoracic aorta were investigated. Rats were pinealectomized (Px) two months before the beginning of the studies. Rings of endothelium-intact and -denuded rat arteries were mounted in isolated tissue baths for the measurements of isometric contractile force. No significant difference was determined between the arterial BP of Px (88.1 +/- 1.9 mmHg) and control (83.8 +/- 1.2 mmHg) rats. All arteries isolated from control and Px rats showed essentially identical contractions in response to phenylephrine, serotonin, calcium, clonidine, vasopressin, and angiotensin-II. Only endothelin-1 (ET-1)-induced contractions in the endothelium-denuded vessels isolated from Px rats were found to be increased to some extent. Pinealectomy did not affect acetylcholine or sodium nitroprusside-induced relaxation in the rat aorta either. These data suggest that reduced melatonin levels two months after pinealectomy did not modify either the vascular reactivity to various vasoconstrictor agents except the partially increased contractile responses to ET-1 in the endothelium-denuded thoracic aortas of Px rats or the endothelium-dependent and -independent relaxations in rat thoracic aorta. Restoration of the increased vascular responses to some vasoconstrictor agents, which were reported previously, may be the reason of why the hypertension is temporary following pinealectomy.

Beneficial effects of melatonin on diaphragmatic contractility and fatigability in Escherichia coli endotoxemic rats.

Sepsis impairs diaphragmatic contractility and endurance capacity and increases diaphragmatic fatigability. Several investigations have shown that administration of a number of free radical scavengers, such as N-acetylcysteine (NAC), protects the diaphragm from the development of endotoxin-mediated diaphragmatic dysfunction. The aim of this study was to evaluate the effects of melatonin (CAS 73-31-4), a naturally occurring potent antioxidant, on diaphragmatic contractility and lipid peroxidation as a marker of oxidative stress in endotoxemic rats. Rats were randomly divided into four groups: control group, endotoxemic group, melatonin group and endotoxemic plus melatonin group. Melatonin was administered by intraperitoneal injection 30 min before endotoxin inoculation to animals. Diaphragmatic function and malondialdehyde (MDA) level analysis as an indicator of lipid peroxidation were assessed 17 h after endotoxin or saline inoculation. Endotoxemia decreased the development of diaphragm fatigue and diaphragmatic MDA levels. The effects of endotoxemia on diaphragmatic contractions and fatigability were reversed and returned to control levels by melatonin administration. However, melatonin did not prevent the increase in muscle MDA content. In conclusion, the present study demonstrated that melatonin attenuated the endotoxin-induced impairment of diaphragm function. This effect of melatonin does not seem to be related to its antioxidant properties.

Melatonin attenuates alpha-adrenergic-induced contractions by increasing the release of vasoactive intestinal peptide in isolated rat penile bulb.

The effects of melatonin on alpha-adrenergic-induced contractions caused by electrical field stimulation (EFS) or the alpha(1)-adrenoceptor agonist phenylephrine (Phe) were investigated in isolated rat penile bulb. Melatonin as well as melatonin receptor agonists N-acetylserotonin and 2-iodomelatonin and melatonin antagonist luzindole attenuated the EFS-induced contractions and the concentration-response curve to Phe. The effect of melatonin on Phe-induced contractions was completely reversed by treatment with tetrodotoxin, guanethidine or vasoactive intestinal peptide (VIP) antagonist. On the other hand, pretreatment with N-methyl-l-arginine, atropine, and luzindole did not reverse the effect of melatonin. Thus, we demonstrated that melatonin at nanomolar concentrations inhibits the alpha-adrenergic responses in isolated rat penile bulb. Since alpha-adrenoceptor blocking agents are known to interfere with detumescence of the erect penis, serum levels or administration of this pineal hormone may affect erectile function. This effect of melatonin may be the result of its allosteric interaction with the presynaptic receptors on VIPergic neurons, which are affected by sympathetic transmission, and then an increase in VIP release from these neurons.