Protective effects of crocin and zinc sulfate on hepatic ischemia-reperfusion injury in rats: a comparative experimental model study

OBJECTIVES

The aim of this study was to investigate the comparative protective effects of separate and combined pretreatment with Cr and ZnSO4 on serum levels of miR-122, miR-34a, liver function tests, protein expression of Nrf2 and p53, and histopathological changes following IR-induced hepatic injury.

MATERIALS AND METHODS

Fifty-six male Wistar rats randomly assigned into seven groups (n=8). Sham (S), IR, crocin pretreatment (Cr), and crocin pretreatment+IR (Cr+IR), ZnSO4 pretreatment (ZnSO4), ZnSO4 pretreatment+IR (ZnSO4+IR) and their combination (Cr+ZnSO4+IR) groups. In sham, ZnSO4 and Cr groups, animals received normal saline (N/S, 2ml/day), Cr (200mg/kg) and ZnSO4 (5mg/kg) for 7 consecutive days (intraperitoneally; i.p), then only laparotomy was performed. In IR, Cr+IR, ZnSO4+IR and Cr+ZnSO4+IR groups, rats received N/S, Cr and ZnSO4 with same dose and time, then underwent a partial (70%) ischemia for 45min that followed by reperfusion for 60min. Blood sample was taken for biochemical and microRNAs assay, tissue specimens were obtained for antioxidants, protein expression, histopathological and immunohistochemical evaluations.

RESULTS

The results showed that Cr and ZnSO4 increased antioxidants activity and expression of Nrf2, decreased serum levels of liver enzymes, miR-122, miR-34a, p53 expression and also ameliorated histopathological abnormality. However, their combination caused more improvement on IR-induced liver injury.

CONCLUSION

This study demonstrated that Cr, ZnSO4 and their combination through increasing antioxidant activity and Nrf2 expression, decreasing the serum levels of liver enzymes, miR-122, 34a, p53 expression, and amelioration of histopathological changes, protected liver against IR-induced injury.

Peripheral and central administration of T3 improved the histological changes, memory and the dentate gyrus electrophysiological activity in an animal model of Alzheimer's disease

The amyloid beta (Aβ) induced Alzheimer's disease (AD) is associated with formation the amyloid plaques, cognitive impairments and decline in spontaneous discharge of neurons. In the current study, we evaluated the effect of subcutaneous (S. C) and intrahippocampal (I. H) administrations of triiodothyronine (T3) on the histological changes, memory and the dentate gyrus (DG) electrophysiological activity in an animal model of AD. Eighty adult male Wistar rats (250-300 g) were divided randomly into five groups: Sham-Operated (Sh-O), AD + Vehicle (S. C), AD + Vehicle (I. H), AD+ T3 (S. C) and AD + T3 (I. H). In order to induce animal model of AD, Aβ (10 ng/μl, bilaterally) were injected intrahippocampally. Rats were treated with T3 and/or normal saline for 10 days. Passive avoidance and spatial memory were evaluated in shuttle box apparatus and Morris water maze, respectively. Neuronal single unit recording was assessed from hippocampal DG. The percent of total time that animals spent in target quarter, the mean latency time (sec), the step through latency and the average number of spikes/bin were decreased significantly in AD rats compared with the Sh-O group (p < 0.001) and were increased significantly in AD groups that have received T3 (S. C and I. H) in compared with AD group (p < 0.01, p < 0.001). Also, formation of amyloid plaques was decreased in AD rats treated with T3.The results showed that T3 injection (S. C and I. H), by reduction of neural damage and increment of neuronal spontaneous activity improved the memory deficits in Aβ-induced AD rats.

Delayed gastric emptying in diabetic rats caused by decreased expression of cystathionine gamma lyase and H2 S synthesis: in vitro and in vivo studies

BACKGROUND

This study aimed to evaluate the role of H₂ S on gastric emptying rate (GER) and also to determine the effect of gastric distention on mRNA and protein expression of cystathionine β-lyase (CBS) and cystathionine γ-synthase (CSE) in diabetic-gastroparetic and normal rats.

METHODS

Adult normal rats intraperitoneally received either propargylglycine (PAG), L-cysteine or NaHS 30 min prior to GER marker (acetaminophen) to investigate H₂ S involvement in GER and the same protocols were performed in diabetes-induced gastroparesis rats. The role of calcitonin gene related peptide (CGRP) neurons in the prokinetic effect of endogenous H₂ S on GER was determined. The level of CBS and CSE expressions in response to gastric distention were also determined. The effect of H₂ S on frequency and tension of spontaneous contractions of gastric smooth muscle strips was investigated.

KEY RESULTS

Our results showed that: (i) H₂ S and L-cysteine increased GER in gastroparetic and normal rats. (ii) The increased levels of CSE expression in response to gastric distention in diabetic rats were lower than in normal rats. (iii) PAG inhibited the excitatory effect of capsaicin on GER and on tension of spontaneous contractions of strips. (iv) Hydrogen sulphide increased the frequency and tension of spontaneous contractions of gastric strip muscles in normal and diabetic rats.

CONCLUSIONS & INFERENCES

The results showed that delayed GER in diabetic rats can be due to down-regulation of H₂ S biosynthesis enzyme, CSE and suggested that a potential prokinetic role for H₂ S to treat the delayed gastric emptying in diabetic patients.

The effects of PM10 on electrocardiogram parameters, blood pressure and oxidative stress in healthy rats: the protective effects of vanillic acid

Particulate matter (PM) inhalation is an established trigger of cardiovascular events such as cardiac arrhythmias that occur within hours to days after exposure. Higher daily PM levels are related to acute increases in systemic arterial blood pressure (BP). The aim of the present study was to evaluate the effects of PM10 on electrocardiogram (ECG) parameters, blood pressure, lipid peroxidation (MDA), xanthine oxidase, and antioxidant enzyme in healthy rats and also to examine the protective effects of vanillic acid (VA) in this respect. Eighty male Wistar rats were divided into eight groups (n = 10), namely control (normal saline, gavage), VAc (10 mg/kg), sham (normal saline, intratracheal instillation), VA (10 mg/kg VA, 10 days gavage +0.1 ml normal saline, intratracheal instillation), PM1 (0.5 mg/kg), PM2 (2.5 mg/kg), PM3 (5 mg/kg), PM3 + VA (5 mg/kg, intratracheal instillation + 10 mg/kg VA, 10 days, gavage) groups. The rats were anesthetized and 0.1 ml of saline as well as a certain concentration of PM10 was instilled into the trachea and it was repeated after 48 h, then 30 min after that, PR interval, QTc, and systolic blood pressure were measured. The activities of antioxidant enzymes, xanthine oxidase (XOX), and malondialdehyde (MDA) were measured in plasma by special Kits. A significant increase in blood pressure (BP), PR interval, QTc, MDA, and XOX and a significant decrease in antioxidant enzyme (CAT, SOD, and GPx) occurred in PM10 groups. Vanillic acid ameliorated blood pressure, QTc, PR interval, XOX, MDA, and increased antioxidant enzymes (SOD, CAT, and GPx) significantly. In the present study, it was shown that PM10 had devastating effects on the heart and blood pressure, probably due to the increased oxidative stress in healthy rats. Vanillic acid could improve the symptoms of PM10 exposure and can be used as an antioxidant agent against the harmful effects of PM10.

Central and peripheral administrations of levothyroxine improved memory performance and amplified brain electrical activity in the rat model of Alzheimer's disease

Alzheimer's disease (AD) is associated with cognitive impairments and a decline in the spontaneous neuronal discharge. In the current study, we evaluated the effect of subcutaneous (S.C.) and intrahippocampal (I.H.) administrations of levothyroxine (LT-4) on the passive avoidance and spatial memory, as well as electrophysiological activity in an animal model of AD. One hundred-sixty male Wistar rats were divided into two main groups. The S.C. group included two Sham and four AD (vehicle or L-T4 25, 50 & 100μg/kg); and the I.H. had consisted of two Sham and two AD (vehicle or L-T4 10μg/kg) subgroups. To make an animal model of AD, amyloid beta (Aβ) plus ibotenic acid (Ibo) were injected I.H. Rats were treated with L-T4 and/or normal saline for ten days. Passive avoidance and spatial memory were evaluated in shuttle box and Morris water maze, respectively. Neuronal single unit recording was assessed from hippocampal dentate gyrus (DG). Results showed that the mean latency time (s) increased significantly (p<0.001) in AD animals and decreased significantly in both S.C. and I.H. L-T4 injected AD animals, compared with the AD group (p<0.001). The percentage of total time that animals spent in goal quarter and the step through latency decreased significantly in AD rats (p<0.001) and increased significantly in both S.C. and I.H. L-T4 injected AD animals in comparison with the AD group (p<0.01, p<0.001). Data showed that the average number of spikes/bin significantly decreased in the AD group (p<0.001). The S.C. and I.H. L-T4 injections in AD rats significantly increased the spike rate in comparison to the AD group (p<0.001). In conclusion, both S.C. and I.H. injections of L-T4 alleviated memory deficits and spontaneous neuronal activity in Aβ-induced AD rats. Also, I.H. microinjection of L-T4 had more beneficial effects on memory and neuronal electrophysiological activity in comparison to S.C. administration.

A study of the mechanisms underlying the anti-inflammatory effect of ellagic acid in carrageenan-induced paw edema in rats

OBJECTIVES

Ellagic acid (EA) has shown antinociceptive and anti-inflammatory effects. Inducible nitric oxide synthase (iNOS), cyclooxygenase 2 (COX-2) enzymes and also cytokines play a key role in many inflammatory conditions. This study was aimed to investigate the mechanisms involved in the anti-inflammatory effect of EA.

MATERIALS AND METHODS

Carrageenan-induced mouse paw edema model was used for induction of inflammation.

RESULTS

The results showed that intraplantar injection of carrageenan led to time-dependent development of peripheral inflammation, which resulted in a significant increase in the levels of tumor necrosis factor α (TNF-α) and interleukin 1 (IL-1) β, nitric oxide (NO) and prostaglandin E2 (PGE2) and also iNOS and COX-2 protein expression in inflamed paw. However, systemic administration of EA (1-30 mg/kg, intraperitoneal [i.p.]) could reduce edema in a dose-dependent fashion in inflamed rat paws with ED50 value 8.41 (5.26-14.76) mg/kg. It decreased the serum concentration of NO, PGE2, aspartate aminotransferase and alanine aminotransferase, and suppress the protein expression of iNOS, COX-2 enzymes, and attenuated the formation of PGE2, TNF-α and IL-1 β in inflamed paw tissue. We also demonstrated that EA significantly decreased the malondialdehyde (MDA) level in liver at 5 h after carrageenan injection. Moreover, histopathological studies indicated that EA significantly diminished migration of polymorphonuclear leukocytes into site of inflammation, as did indomethacin.

CONCLUSIONS

Collectively, the anti-inflammatory mechanisms of EA might be related to the decrease in the level of MDA, iNOS, and COX-2 in the edema paw via the suppression of pro-inflammatory cytokines (TNFα, IL1 β), NO and PGE2 overproduction.

Preventive effects of procyanidin A2 on glucose homeostasis, pancreatic and duodenal homebox 1, and glucose transporter 2 gene expression disturbance induced by bisphenol A in male mice

Procyanidins (PCs) as oligomeric compounds with antidiabetic properties formed from catechin and epicatechin molecules. Bisphenol A(BPA) is a common chemical material use in food and beverage packaging. The aim of this study was to explore the protective effects of procyanidin A2 (PCA2) against glucose homeostasis disturbance and gene expression of pancreatic and duodenal homebox 1 (Pdx1) as well as glucose transporter 2 (Glut2) induced by BPA in male mice. First tested these five concentrations of PCA2 (3 - 300 μM) alone and in combination with BPA(100 μg/L), on insulin secretion from isolated islets at in vitro condition. Next, examined the influence of BPA and PCA2 on islet apoptosis using flowcytometry. At in vivo condition, the BPA (100 μg/kg) and PCA2 (10 μmol/kg) administered for 20 days then, blood glucose and insulin, Pdx1 and, Glut2 genes expression, and oxidative stress markers examined. The results indicated that PCA2 strongly prevents islet cells apoptosis induced by BPA and, co-administration of PCA2 and BPA modified hyperglycemia. BPA reduced Pdx1 and Glut2 mRNA expression and antioxidant level in pancreas tissue, whereas PCA2 prevented from these effects. The findings from these studies suggest that use of PCA2 rich plants have preventive effects on hyperglycemia, and type 2 diabetes.

Mucosal acidification increases hydrogen sulfide release through up-regulating gene and protein expressions of cystathionine gamma-lyase in the rat gastric mucosa

OBJECTIVES

This study was performed to investigate the effects of mucosal acidification on mRNA expression and protein synthesis of cystathionine gamma lyase (CSE), cystathionine beta synthase (CBS), and mucosal release of H2S in gastric mucosa in rats.

MATERIALS AND METHODS

Thirty-two rats were randomly assigned into 4 groups (8 in each), including: the control group, HCl (10 mM) treated group, HCl (100 mM) treated group, and one group to study the effect of Nω-Nitro-L-arginine methyl ester hydrochloride (L-NAME). Anesthetized rats underwent tracheostomy and midline laparotomy. Ninety min after the instillation of neutral or acidic solutions, animals were sacrificed and the gastric mucosa was collected to measure the H2S concentration by ELISA method and to quantify mRNA expression of CSE and CBS by quantitative real-time PCR (qRT-PCR). Protein synthesis was also detected by Western blot method.

RESULTS

Mucosal acidification with 10 and 100 HCl, significantly increased mucosal levels of H2S (P<0.01 and P<0.001) and mRNA (P<0.01 and P<0.001) and protein expressions of CSE (P<0.01 and P<0.001). L-NAME treatment reversed H2S release to control level.

CONCLUSION

Our findings indicated that mucosal acidification with HCl increased mucosal release of H2S through upregulation of CSE gene and its protein expression. This effect is mainly mediated through the involvement of nitric oxide.

Protective Effect of Crocin on Gastric Mucosal Lesions Induced by Ischemia-Reperfusion Injury in Rats

The present study aimed to evaluate the protective effect of crocin on gastric mucosal lesions caused by ischemia-reperfusion (I/R) injury in rats. Forty male rats were randomly divided into sham, control (I/R injury) and three crocin-pretreated groups. To induce I/R lesions, the celiac artery was clamped for 30 min and then the clamp was removed to allow reperfusion for 3 h. Pretreated-rats received crocin (7.5, 15 or 30 mg/kg, i.p.) 30 min prior to the induction of I/R injury. Samples of gastric mucosa were collected to measure the following variables: 1 mRNA expression of superoxide dismutase (SOD) and glutathione peroxidase (Gpx) by RT-PCR; 2 activity of superoxide dismutase and glutathione peroxidase and 3 tissue levels of malonyldehaldehyde (MDA). Pretreatment with crocin decreased the total area of gastric lesions. Messenger RNA expressions of SOD and Gpx in control I/R injury rats were significantly decreased as compared with sham-operated group (P<0.001). Crocin pretreatment 30 min prior to I/R injury significantly increased mRNA expressions of SOD and Gpx genes. The gastric mucosal activities of SOD and Gpx in control I/R injury rats were significantly lower than in crocin-pretreated groups (P<0.01). Crocin pretreatment decreased mucosal production of MDA. Our findings showed the protective effect of crocin on gastric mucosa against ischemia-reperfusion injury. These effects of crocin were mainly mediated by increasing the mRNA expressions- and the enzyme activity of SOD and Gpx as well as by inhibiting the production of free radicals.

Hydrogen sulfide upregulated mRNA expressions of sodium bicarbonate cotransporter1, trefoil factor1 and trefoil factor2 in gastric mucosa in rats

Hydrogen sulfide (H₂S) has been shown to protect the gastric mucosa through several protective mechanisms but till now its effect on mRNA expression of sodium bicarbonate cotransporter 1 (NBC1), trefoil factor1 (TFF1) and trefoil factor2 (TFF2) was not investigated. This study was aimed to evaluate the effect of H₂S on mRNA expression of NBC1, TFF1 and TFF2 in rat gastric mucosa in response to gastric distention. Thirty two rats were randomly assigned into four equal groups. They were control (C), distention (D), propargylglycine (PAG)-, and NaHS-treated groups. To evaluate the effect of exogenous and endogenous H₂S on gene expression of NBC1, TFF1 and TFF2, two groups of rats were received H₂S donor, intra-peritoneal NaHS (80 µg Kg^-1), and PAG (50 mg kg^-1), accompanied to stimulate the gastric acid secretion, respectively. Under general anesthesia and laparotomy, a catheter was inserted into the stomach through duodenum for instillation of isotonic saline for gastric distention. Ninety min after beginning the experiment, animals were sacrificed and the gastric mucosa was collected to determine total acid content of gastric effluents and to quantify the mRNA expression of studied genes by quantitative real-time polymerase chain reaction (qRT-PCR). Results showed that A) gastric distention increased the level of mRNA expressions of NBC1, TFF1 and TFF2; B) these levels in NaHS-treated rats were significantly higher than those in Distention group; and C) PAG decreased the expression levels of NBC1 and TFF1. The Findings showed H₂S upregulated gene expression of NBC1, TFF1 and TFF2 in gastric mucosa.

Gastric acid induces mucosal H2S release in rats by upregulating mRNA and protein expression of cystathionine gamma lyase

It is well known that hydrogen sulfide (H2S) protects the gastric mucosa against gastric acid and other noxious stimulants by several mechanisms but until now the effect of gastric acid on H2S production has not been evaluated. This study was performed to determine the effect of basal and stimulated gastric acid secretion on mRNA and protein expression of cystathionine gamma lyase (CSE) and cystathionine beta synthase (CBS), and on mucosal release of H2S in rats. Seventy-two male rats were randomly assigned into 9 groups (8 in each)-control, distention, and pentagastrin-induced gastric acid secretion groups. The effects of 15% alcohol solution, propargylglycine (PAG), L-NAME, and pantoprazole were also investigated. Under anesthesia, animals underwent tracheostomy and midline laparotomy. A catheter was inserted into the stomach through the duodenum for gastric washout. At the end of the experiments, the animals were killed and the gastric mucosa was collected to measure H2S concentration and to quantify mRNA expression of CSE and CBS by quantitative real-time PCR, and expression of their proteins by western blot. Basal and stimulated gastric acid secretion increased mucosal levels of H2S, and mRNA and protein expression of CSE. Pantoprazole and L-NAME reversed H2S release and restored protein expression of CSE to the control level. Pantoprazole, but not propargylglycine, pretreatment inhibited the elevated level of protein expression of eNOS in response to distention-induced gastric acid secretion. Our findings indicated that NO mediated the stimulatory effect of gastric acid on H2S release and protein expression of CSE.

A preliminary study of the anti-inflammatory and anti-apoptotic effects of crocin against gastric ischemia-reperfusion injury in rats

The aim of the present study was to investigate the protective effect of crocin on gastric mucosal lesions caused by ischemia-reperfusion (I/R) injury in rats. Thirty-two male rats were randomly divided into sham, I/R, I/R + crocin pretreatment and crocin alone groups. To induce I/R lesions, the celiac artery was clamped for 30 min, and the clamp was then removed to allow reperfusion for 3 h. Crocin-pretreated rats received crocin (15 mg/kg, i.p.) 30 min prior to the induction of I/R injury. Samples of gastric mucosa were collected to quantify the protein expression of caspase-3, an apoptotic factor, and inducible nitric oxide synthase (iNOS), a pro-inflammatory protein, by Western blot. Pretreatment with crocin decreased the total area of gastric lesions and decreased the protein expression levels of caspase-3 and iNOS induced by I/R injury. Our findings showed a protective effect of crocin in gastric mucosa against I/R injury. This effect of crocin was mainly mediated by reducing the protein expression of iNOS and caspase-3.

Protective effects of vitamin B6 alone and in combination with L-cysteine and NaHS on ethanol and indomethacin-induced gastric lesions in mice

OBJECTIVES

This study was undertaken to investigate the protective effects of vitamin B6, cofactor for cystathionine-γ lyase and cystathionine-β synthase (producers of H2S), alone and in combination with L-cysteine, H2S precursor, on indomethacin-, and ethanol-induced gastric lesions in male NMRI mice.

MATERIALS AND METHODS

Fasted male NMRI mice were randomly assigned into 12 groups (7 in each). The gastroprotective activity of vitamin B6 alone and in combination with L-cysteine and sodium hydrosulfate (NaHS) was evaluated against ethanol-, and indomethacin-induced gastric lesions. The animals were received vehicle, vitamin B6, L-cysteine, L-cysteine+vitamin B6, NaHS or NaHS+B6 before the induction of gastric lesions by ethanol (50%, 0.5 ml/25 g of body weight, orally) or indomethacin (40 mg/kg, orally). One and five hours after the administration of ethanol and indomethacin, respectively, the animals were sacrificed using anesthetics. The stomachs were removed, rinsed with normal saline and assessed for gastric wall mucus changes.

RESULTS

Pretreatment with L-cysteine, sodium hydrosulfate, and vitamin B6 significantly decreased the total area of gastric lesions (P<0.01). The mucus production in L-cysteine-, sodium hydrosulfate-, and vitamin B6-treated animals were significantly higher than in control rats P<0.05). The gastroprotective activity of L-cysteine and sodium hydrosulfate in combination with vitamin B6 were higher than when administered alone (P<0.05).

CONCLUSION

The result of this survey showed that the protective activity of L-cysteine and sodium hydrosulfate enhances in the presence of vitamin B6.

The anti-inflammatory and anti-apoptotic effects of gallic acid against mucosal inflammation- and erosions-induced by gastric ischemia-reperfusion in rats

The present study aimed to evaluate the protective effect of gallic acid on gastric mucosal lesions caused by ischemia-reperfusion (I/R) injury in rat. Forty male rats were randomly divided into sham, control (I/R injury) and three gallic acid-pretreated groups. To induce I/R lesions, the celiac artery was clamped for 30 min and then the clamp was removed to allow reperfusion for 6 hr. Pretreated rats received gallic acid (15, 30 or 60 mg kg(-1), intraperitoneally) 30 min prior to the induction of I/R injury. Macroscopic and microscopic evaluations of the areas of ulceration were compared. Samples of gastric mucosa were collected to evaluate the protein expression of pro-apoptotic factor, caspase-3, and pro-inflammatory enzyme, inducible nitric oxide synthase (iNOS) using western blot. Pretreatment with gallic acid decreased the total area of gastric lesions. Gallic acid at 30 mg kg(-1) decreased the levels of protein expression of caspase-3 and iNOS induced by I/R injury. Our findings showed the protective effect of gallic acid on gastric mucosa against ischemia-reperfusion injury. This effect of gallic acid was mainly mediated by reducing protein expression of iNOS and caspase-3.

Involvement of L-arginine/NO/cGMP/K(ATP) channel pathway in the peripheral antinociceptive actions of ellagic acid in the rat formalin test

The present study was conducted to evaluate the local antinociceptive actions of EA and the possible involvement of l-arginine/NO/cGMP/KATP channel pathway in this effect using formalin test in rats. To evaluate the involvement of l-arginine/NO/cGMP/KATP channel pathway in the antinociceptive action of EA, rats were pre-treated intraplantarlly with l-NAME (NOS inhibitor, 25-100μg/paw), methylene blue (guanylyl cyclase inhibitor, 100-400μg/paw), glibenclamide (ATP-sensitive K(+) channel blocker, 25-100μg/paw), l-arginine (a nitric oxide precursor, 25-100μg/paw) and sodium nitroprusside (125-500μg/paw). The local peripheral ipsilateral, but not contralateral, administration of EA into the right paw (30-300μg/paw) produced a dose-related antinociception during both early and late phases of formalin test which is comparable with morphine (25μg/paw). Moreover, local pre-treatment with l-NAME, methylene blue and glibenclamide dose-dependently prevented EA (100μg/paw)-induced antinociception in late phase. Additionally, administration of l-arginine and sodium nitroprusside significantly potentiated the antinociception induced by EA in the late phase. However, these treatments had no significant effect on antinociceptive response of EA in the early phase of the formalin test. The results of the present study showed that EA-induced local peripheral antinociception during the both phases of formalin test. Also, our data suggested the activation of the l-arginine/NO/cGMP/KATP channels pathway in EA-induced antinociception in late phase of formalin test. Topical application of EA by ointment or jelly might be a useful method to relieving the inflammatory pain states.

The protective activity of noscapine on renal ischemia-reperfusion injury in male Wistar rat

OBJECTIVES

Bradykinin is a part of the kinin-kallikrein system which is involved in ischemia-reperfusion injury via B1 and B2 receptors. Noscapine is a non-competitive antagonist of bradykinin receptors. Noscapine has been reported to to be able to protect some organs against ischemia-reperfusion injury but its effect on renal ischemia-reperfusion injury (RIR) in rats is unknown. Therefore, the present study was designed to evaluate the effect of noscapine on renal ischemia-reperfusion injury in rats.

MATERIALS AND METHODS

Twenty four rats were randomly assigned to four groups; sham, RIR control, pre-and post-treatment with noscapine. To induce RIR injury, 20 days after right nephrectomy, animals underwent a midline laparotomy and the renal artery was clamped for 40 min to induce ischemia, and the clamp was then removed to allow reperfusion for 48 hr. Animals received noscapine or vehicle 1 hr before RIR or just prior to reperfusion. At the end of the experiment, animals were killed by cardiac exsanguination. Blood samples were collected to assess blood urea nitrogen (BUN) and creatinine. The kidneys were also removed for histopathlogical and western-blot analysis.

RESULTS

Noscapine treatment 1 hr before RIR or just prior to reperfusion protects the renal tissue structure as compared with the control. The expression levels of the studied inflammatory mediators, TNF-α and MCP-1in pretreated-, and treated-noscapine groups decreased as compared with the control group. The levels of BUN and creatinine in pre-, and post-treated noscapine groups were significantly lower than in control animals.

CONCLUSION

Noscapine protects renal tissue structure and function against RIR through down-regulation of the inflammatory mediators.

Progesterone and cilostazol protect mice pancreatic islets from oxidative stress induced by hydrogen peroxide

Reactive oxygen species and oxidative stress impair β-cell function and reduce insulin secretion. It has been shown that progesterone and cilostazol possess antioxidant properties. The present study was aimed to investigate in-vitro pretreatment effect of progesterone and cilostazol on insulin secretion as well as their protective effects against hydrogen peroxide-induced oxidative stress in pancreatic isolated islets from mouse. Pancreatic islets were isolated from 84 male NMRI mice (25-30 g) by collagenase digestion method and pretreated for 48 h with cilostazol (10 μM), progesterone (0.5 μM) and glibenclamide (10 μM) in culture medium. Then islets were exposed to hydrogen peroxide (H2O2. 500 μM) for 2 h. Next, culture mediums containing glucose concentration of 2.8 mM or 16.7 mM were added to them and incubated in this status for 1 h. At the end, the rate of insulin output from islets, lipid peroxidation and antioxidant enzymes activities in islet tissues were assayed. Exposure of islets to H2O2, resulted in a significant decrease in insulin secretion, superoxide dismutase and catalase activities (P < 0.001). Also islets malondialdehyde levels were increased by H2O2, after addition of 2.8 mM (P < 0.05) and 16.7 mM (P < 0.001) glucose. 48 h pretreatment of islets with cilostazol and progesterone, significantly reverted back this changes (P < 0.05). Results of present study showed that cilostazol and progesterone protect mice pancreatic islets against H2O2-induced oxidative stress. At the end, our results suggested that protective effects of progesterone and cilostazol are mediated by augmentation the antioxidant defence system of islets.

Bronchodilatory effect of hydrogen sulfide in rat

OBJECTIVE(S)

The aims of present study were to elucidate the effect of NaHS as a H2S donor on precontracted rat trachea smooth muscle, role of epithelium and nitric oxide in this action.

MATERIALS AND METHODS

Tracheal rings from male adult Wistar rats were isolated and mounted in an organ bath containing Krebs-Henseleit solution under 1.5 g resting tension and contractions were recorded isometrically. After equilibrium period (60 min), cumulative concentrations of NaHS (0.2-1.2 mM) were applied on the tracheal basal tone or on the plateau of contractions induced by KCl (60 mM) or carbachol (CCh, 0.55 μM) in the absence and presence of certain antagonists and inhibitors.

RESULTS

The tracheal basal tone was unaffected by NaHS but tracheal contractions induced by KCl and CCh were attenuated by NaHS in a concentration-dependent manner (P< 0.001). Removing the tracheal epithelial did not attenuate the NaHS spasmolytic effect in the tissue precontracted by KCl and CCh. The bronchodilatory effect was unaffected by tissue incubation (30 min, 1 μM) with, glibenclamide, propranolol, indomethacin, methylene blue (10 μM), and L-NAME (300 μM).

CONCLUSION

It seems that bronchodilatory effect of H2S was not mediated by KATP channels, β-adrenoceptors, epithelium and production of nitric oxide, cGMP and prostaglandins. Since CCh and KCl activate Ca(2+) influx and CCh promotes Ca(2+) from intracellular pool as well, therefore, we may conclude that the relaxant effect of NaHS was mediated by the Ca(2+) influx blockade and cholinergic receptors inactivation. This preliminary study shows the possible therapeutical property of H2S in obstructive pulmonary diseases.

Spasmogenic Activity of the Seed of Terminalia chebula Retz in Rat Small Intestine: In Vivo and In Vitro Studies

BACKGROUND

Terminalia chebula Retz is traditionally used to relieve constipation. The current study was performed to investigate the pharmacological action of aqueous extract of Terminalia chebula seeds (ATC) in vitro and in vivo.

METHODS

Terminal pieces of rat ileum were suspended in organ bath containing Tyrode solution. The ileum spontaneous motility frequency and contractility were recorded isotonically. To induce ileal contraction, carbachol and ATC were added to the organ bath. In addition, the effect of hexamethonium, indomethacin, atropine, and verapamil on the ATC-induced ileal contractions was also investigated. The effectiveness of ATC on relieving morphine-induced constipation was investigated in an in vivo study by measuring the faecal number, faecal water content, and intestinal transit ratio.

RESULTS

ATC increased the frequency of ileum motility and tension of contraction dose-dependently (P < 0.05). Responses induced by ATC were inhibited by pre-treatment of the tissue with verapamil. The ATC activities were not affected by atropine, hexamethonium, and indomethacin. The faecal number and faecal water content were increased dose-dependently by ATC (P < 0.05).

CONCLUSION

The excitatory effects of ATC on ileal contractile frequency and tension are possibly mediated through Ca(2+) channels activation. The results of the present study support the traditional usage of ATC for the treatment of constipation.

Evaluation of the antidiabetic and antilipaemic activities of the hydroalcoholic extract of phoenix dactylifera palm leaves and its fractions in alloxan-induced diabetic rats

BACKGROUND

The antidiabetic and antilipaemic effects of Phoenix dactylifera leaf extract (PDE) and its fractions were investigated in various rat models.

METHODS

Diabetes was induced in male Wistar rats by alloxan monohydrate. Diabetic animals were randomly divided into 8 groups (1 diabetic control and 7 treated groups). Diabetic control animals received saline (5 mL/kg) orally, whereas the treatment groups received different doses of PDE (100, 200, and 400 mg/kg), PDE fractions (50, 100, and 200 mg/kg), or glibenclamide (4 mg/kg) orally once a day for 14 days. Blood was withdrawn for glucose determination on the 1(st), 6(th), 10(th), and 14(th) days. The rats were fasted overnight and then sacrificed on the 14(th) day; blood was collected for biochemical evaluation, including the levels of blood glucose, plasma insulin, serum triglyceride, and cholesterol.

RESULTS

Subacute administration of PDE or its fractions in alloxan-induced diabetic rats significantly reduced blood glucose (P < 0.01). Water intake, serum triglyceride, and cholesterol also decreased in treated animals compared with the control group (P < 0.01). Plasma insulin level increased in the treated groups relative to the control group (P < 0.01).

CONCLUSION

The results suggested that PDE exhibits antidiabetic and antilipaemic effects in alloxan-induced diabetic rats.

Gastric secretions affected by esophageal distention in the rat

BACKGROUND

The effect of esophageal distention (ED) on gastric motility has been well documented, but only a few investigations have been carried out about the effect of ED on gastric secretions. The aim of this study was to investigate the effect of ED on gastric acid and pepsin secretions and the mechanisms involved.

METHODS

Male adult Wistar rats (200-240 g) were anesthetized by urethane [1.2 g/kg, intraperitoneally (i.p.)] and underwent tracheostomy and laparotomy. A catheter was inserted in the stomach through the duodenum for gastric washout and distention followed by the esophageal distention by a balloon (0.3 ml, 10 min). Gastric acid secretion was stimulated by gastric distension (1.5 ml/100 g body weight), pentagastrin (20 microg/kg, i.p.), or insulin (0.6 IU/kg, i.p.). Pepsin secretion was stimulated by carbachol (20 microg/kg, i.p.). Effects of cervical vagotomy and reserpine (1 mg/kg, i.p.) were also investigated.

RESULTS

Gastric distention-, pentagastrin-, and insulin-stimulated gastric acid secretion was reduced by esophageal distention (P < 0.001, P < 0.05, and P < 0.05, respectively). Carbachol-induced pepsin secretion was also attenuated by esophageal distention (P < 0.05). Cervical vagotomy abolished the inhibitory effect of ED on pentagastrin-induced gastric acid secretion. In reserpinized rats, ED reduced the basal gastric acid secretion (P < 0.05).

CONCLUSIONS

These results indicate that the vagus nerves are involved in the inhibitory effect of esophageal distension on gastric secretory function.

Antiulcerogenic effect of Securigera securidaca L. seed extract on various experimental gastric ulcer models in rats

Securigera securidaca belongs to the family Fabaceae is used in Iranian folk medicine to treat gastric disturbances. The present study was undertaken to evaluate the Securigera securidaca seed hydroalcoholic extract (SSE) and its subfractions for their gastroprotective effect in rat. Acute gastric ulceration in rats was produced by oral administration of ethanol (100%; 1 mL/200 g of body weight) or water immersion restraint-stress (5 h, water immersion restraint stress at 20-22 degrees C). Ranitidine (100 mg kg(-1), p.o.) was used as the reference antiulcer drug. After ethanol administration, the gastric wall mucus was examined. Chronic gastric ulceration was produced by injection of acetic acid in rat gastric subserosa. The antisecretory effect of the extract and its subfractions (ethyl acetate, chloroform and aqueous fractions) were investigated in pylorus-ligated rats. Administration of SSE significantly inhibited gastric mucosa damage induced by ethanol, water immersion restraint-stress and acetic acid in a dose-dependent manner. In pylorus ligature rats, SSE and its subfractions significantly reduced the basal gastric acid secretion and total acidity; moreover, it inhibited the increase in total acidity induced by carbachol. However, the antisecretory effect of the chloroform fraction was more potent than two other fractions. Administration of SSE did not affect the gastric mucus production. The results obtained in the present study indicate that the SSE has gastroprotective and antisecretory effects on gastric mucosa in rats.

Effect of esophageal distention on basal and stimulated gastric acid secretion in rats

BACKGROUND

It is well established that the esophageal distention (ED) leads to gastric relaxation, partly by vago-vagal reflex, but till now, the effect of ED on gastric acid secretion has not been investigated. The aim of this study was to investigate the effect of ED on basal and stimulated gastric acid secretion.

METHODS

Adult male Wistar rats (200-240 g) were deprived of food but not the water 24 h before the experiments. Under urethane anesthesia (1.2 g/kg, i.p.), animals underwent tracheostomy and laparotomy. A catheter was inserted in the stomach through duodenum for gastric distention and gastric washout and the esophagus was cannulated with a distensible balloon orally to distend esophagus (0.3 ml, 10 min). Gastric acid secretion was stimulated by gastric distention, carbachol (4 microg/kg, i.p.) or histamine (5 mg/kg, s.c.). Effects of vagotomy, NG-nitro-L-arginine methyl ester (L-NAME, 10 mg/kg, i.v.) and also hexamethonium were investigated.

RESULTS

Basal and gastric distention- and carbachol, histamine-stimulated acid secretion were reduced by the ED (P<0.05, P<0.0001, P<0.01 and P<0.02, respectively). L-NAME (10 mg/kg, i.v.) elevated the acid output (P<0.002). Vagotomy reduced the inhibitory effect of the esophagus distention on gastric distention-induced acid secretion (P<0.01).

CONCLUSION

These results indicate that the vagus nerves are involved in the inhibitory effect of the ED on the basal and stimulated gastric acid secretion. Furthermore, nitric oxide could be involved.