Quercetin Attenuates Endoplasmic Reticulum Stress and Apoptosis in TNBS-Induced Colitis by Inhibiting the Glucose Regulatory Protein 78 Activation.

Background: The inflammatory bowel diseases (IBD) are significantly influenced by apoptosis and endoplasmic reticulum (ER) stress. Aims: To investigate the effects of quercetin on ER stress-mediated apoptosis in a trinitrobenzene sulfonic acid (TNBS) induced experimental IBD model. Study Design: In vivo animal experimental study. Methods: To demonstrate the effect of quercetin in an experimental colitis model, Control, TNBS, and TNBS+quercetin groups were created with 24 Wistar Albino rats. Colitis was induced by intrarectal administration of 25 mg TNBS. In the TNBS+quercetin group, intragastrically 100 mg/kg quercetin was given for 7 days, immediately after colitis induction. In the TNBS-induced experimental IBD model, we evaluated the effects of quercetin on colonic epithelial cell apoptosis, oxidative stress, ER stress, the mitogen-activated protein kinase c-Jun N-terminal kinase, and the nuclear factor kappa B immunoreactivities, the levels of myeloperoxidase and tumor necrosis factor-α, the disease activity index with colonic histopathologic changes. Results: TNBS administration induced an elevated level of disease activity and oxidative stress indices, inflammation markers, and an increase in the immunoreactivities of nuclear factor kappa B and the mitogen-activated protein kinase c-Jun N-terminal kinase in the colon of the colitis group. Glucose regulatory protein 78, caspase-12 immunoreactivities, and epithelial cell apoptosis also were shown in the colon. However, quercetin improved TNBS-induced histopathological alterations, apoptosis, inflammation, oxidative stress, and ER stress. Conclusion: This study suggests that quercetin has a regulatory effect on ER stress-mediated apoptosis, and thus may be beneficial in treating IBD.

Sitagliptin and fucoidan prevent apoptosis and reducing ER stress in diabetic rat testes.

Sitagliptin increases the levels of incretin hormones and stimulates a decrease in blood glucose levels, by blocking the DPP4 enzyme. We have very limited information about impact of sitagliptin on male genital system and relationship between sitagliptin/diabetes/ER. Fucoidan can be effective in blood glucose homeostasis. We goal to explain of the effect of sitagliptin and introduce an approach of fucoidan treatment in experimental diabetes in male rats. Fifty-eight Wistar albino rats were divided into C-control group and D-diabetes group: 60 mg/kg streptozotocin intraperitoneal (i.p.); DS group: STZ + 10 mg/kg sitagliptin intragastric (i.g.); DF group: STZ + 100 mg/kg fucoidan i.p.; and DSF group: STZ + 10 mg/kg sitagliptin + 100 mg/kg fucoidan. A significant decrease was detected when DS, DF and DSF groups compared to group D in blood glucose levels, basement membrane thickness and also apoptotic cell/tubule index, pJNK, caspase 3, caspase 12, GRP78, CHOP and DPP4. Sitagliptin and fucoidan have been found to be effective in blood glucose homeostasis and reducing the expression of certain proteins that lead to apoptosis and especially the proteins in the ER stress pathway. Therefore, we think that both sitagliptin and fucoidan can be effective in preventing or eliminating histopathological damages in diabetic testicular tissues, and their treatment effects can be used more.

The effects of epidermal growth factor on early burn-wound progression in rats.

After burns, protecting tissues by medicines in the zone of stasis reduces the width and depth of injury. This study's goal was to reduce burned tissue damage in the zone of stasis using epidermal growth factor (EGF). Forty-eight Wistar rats were separated into three groups. In all groups, the burn procedure was applied following the comb burn model. In Group 1, no postburn treatment was administered. In Group 2, physiological saline solution (0.3 cc) was injected intradermally and in Group 3, EGF (0.3 cc) was injected intradermally into stasis zone tissues after the burn procedure. Surviving tissue rates were 24.0% in Group 1, 25.3% in Group 2, and 70.2% in Group 3. The average numbers of cells stained with Nrf2, HO-1, and the number of apoptotic cells were 230, 150, and 17.5 in Group 1, 230, 145, and 15.0 in Group 2, and 370, 230, and 0 in Group 3, respectively. Values in Group 3 were found to be statistically significantly different than those of Groups 1 and 2; there was no difference between Groups 1 and 2. This study shows that EGF protects zone of stasis tissue from burn damage.

Curcumin counteracts cisplatin-induced nephrotoxicity by preventing renal tubular cell apoptosis.

Curcumin has several biological functions particularly antioxidant and anti-inflammatory. The aims of this study are determination of the protective effects of curcumin on cisplatin-induced renal tubular cell apoptosis and related pathways in kidney. Eighteen male Wistar albino rats were randomly divided into three groups (n = 6): the control, cisplatin (CP), and cisplatin + curcumin (CP + CUR). Acute renal damage was induced by single dose of cisplatin (7.5 mg/kg) injected by intraperitoneally (i.p). The animals of curcumin-treated group were received daily 200 mg/kg curcumin per os (po), starting from 2 days before the injection of cisplatin to the day of sacrifice. Forty-eight hours after cisplatin injection, samples of cardiac blood and kidneys were harvested from the animals. In this study, the major finding is that curcumin treatment ameliorates the following conditions associated with cisplatin-induced nephrotoxicity: (1) the development of kidney injury (histopathology), (2) inflammatory responses [myeloperoxidase (MPO) and tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1ß), IL-6, IL-10 levels], (3) the degree of lipid peroxidation [malondialdehyde (MDA) level], (4) renal tubular cell apoptosis (active caspase-3) and expression of related proteins [p53, Fas, and Fas ligand (Fas-L)] by immunohistochemistry, (5) renal dysfunction (serum urea and creatinine). In a conclusion, this study suggests that curcumin has antiapoptotic effect against cisplatin nephrotoxicity, in addition to anti-inflammatory and antioxidant properties.

MAPK immunoreactivity in streptozotocin-induced diabetic rat testis.

PURPOSE: To evaluate the alterations of two mitogen-activated protein kinases (MAPK)s, extracellular signal regulated kinase (ERK) and c-Jun NH2 terminal kinase (JNK), in the testes of male rats with experimental diabetes. METHODS: Twenty males Sprague-Dawley rats were randomly divided into a control group (n=8) and a diabetes group (administration of 40 mg/kg/day streptozotocin (STZ) for five sequential days, n=12). After six weeks, testicular biopsy samples were obtained for light microscopy and immunohistochemical methods. RESULTS: The PCNA (proliferating cell nuclear antigen) index was significantly decreased in the diabetes group (p=0.004) when compared to the control group. Both total (t)-ERK and phosphor (p)-ERK immunoreactivities were significantly decreased in the diabetes group (p=0.004, p<0.001, respectively). The t-JNK immunoreactivity was unchanged in both groups (p=0.125), while p-JNK immunoreactivity was significantly increased in the diabetic group (p=0.002). CONCLUSIONS: The decrease of androgen levels in the course of diabetes may contribute to the decrease of the immunoreactivities of t-ERK and p-ERK. JNK may be activated due to the changes in various cytokines and chemochines that participate in the oxidative stress process of diabetes. Therefore, testicular apoptosis may occur and lead to infertility associated with diabetes.

MAPK immunoreactivity in streptozotocin-induced diabetic rat testis

PURPOSE: To evaluate the alterations of two mitogen-activated protein kinases (MAPK)s, extracellular signal regulated kinase (ERK) and c-Jun NH2 terminal kinase (JNK), in the testes of male rats with experimental diabetes. METHODS: Twenty males Sprague-Dawley rats were randomly divided into a control group (n=8) and a diabetes group (administration of 40 mg/kg/day streptozotocin (STZ) for five sequential days, n=12). After six weeks, testicular biopsy samples were obtained for light microscopy and immunohistochemical methods. RESULTS: The PCNA (proliferating cell nuclear antigen) index was significantly decreased in the diabetes group (p=0.004) when compared to the control group. Both total (t)-ERK and phosphor (p)-ERK immunoreactivities were significantly decreased in the diabetes group (p=0.004, p<0.001, respectively). The t-JNK immunoreactivity was unchanged in both groups (p=0.125), while p-JNK immunoreactivity was significantly increased in the diabetic group (p=0.002). CONCLUSIONS: The decrease of androgen levels in the course of diabetes may contribute to the decrease of the immunoreactivities of t-ERK and p-ERK. JNK may be activated due to the changes in various cytokines and chemochines that participate in the oxidative stress process of diabetes. Therefore, testicular apoptosis may occur and lead to infertility associated with diabetes. .

N-Acetylcysteine counteracts oxidative stress and protects alveolar epithelial cells from lung contusion-induced apoptosis in rats with blunt chest trauma.

The aim of this study was to investigate the protective effects of N-acetylcysteine (NAC) on peroxidative and apoptotic changes in the contused lungs of rats following blunt chest trauma. The rats were randomly divided into three groups: control, contusion, and contusion + NAC. All the rats, apart from those in the control group, performed moderate lung contusion. A daily intramuscular NAC injection (150 mg/kg) was given immediately following the blunt chest trauma and was continued for two additional days following cessation of the trauma. Samples of lung tissue were taken in order to evaluate the tissue malondialdehyde (MDA) level, histopathology, and epithelial cell apoptosis using terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay and active caspase-3 immunostaining. In addition, we immunohistochemically evaluated the expression of surfactant protein D (SP-D) in the lung tissue. The blunt chest trauma-induced lung contusion resulted in severe histopathological injury, as well as an increase in the MDA level and in the number of cells identified on TUNEL assay together with active caspase-3 positive epithelial cells, but a decrease in the number of SP-D positive alveolar type 2 (AT-2) cells. NAC treatment effectively attenuated histopathologic, peroxidative, and apoptotic changes, as well as reducing alterations in SP-D expression in the lung tissue. These findings indicate that the beneficial effects of NAC administrated following blunt chest trauma is related to the regulation of oxidative stress and apoptosis.

Protective effect of sildenafil on liver injury induced by intestinal ischemia/reperfusion.

BACKGROUND: This study evaluated the protective effect of sildenafil on liver injury induced by intestinal ischemia-reperfusion. METHODS: Forty female Sprague Dawley rats were divided into 4 groups: sham-control (SC), ischemia (I), ischemia-reperfusion (IR), and ischemia-reperfusion+sildenafil (SIL; sildenafil gavaged at 50mg/kg before operating). A 2-h ischemia-reperfusion was performed by clamping the superior mesenteric artery. Liver function, plasma alanine (ALT) and aspartate (AST) aminotransferase, and intestinal and liver malondialdehyde (MDA) were measured at the end of the experiment. Intestinal and liver tissue damage was examined by histology. Liver samples were immunologically stained for endothelial nitric oxide synthase (eNOS) and proliferating cell nuclear antigen (PCNA). RESULTS: The ALT and AST levels were highest in the IR group and were lower in the SIL group (p<0.05). Intestinal MDA levels were statistically higher in the IR group than in the SC, I and SIL groups. Liver MDA levels were significantly higher in the IR group than in the I and SC groups (p<0.05) and higher than in the SIL group (p>0.05). Intestinal damage based on Chiu scoring was more severe in the IR than in the SIL group (p<0.05). Sildenafil reduced damage and also increased eNOS and PCNA immunoreactivity in liver tissue. CONCLUSIONS: Sildenafil shows a protective effect on intestinal ischemia-reperfusion-induced liver injury, possibly by decreasing vascular resistance through increased nitric oxide levels.

Vitamin E modulates apoptosis and c-jun N-terminal kinase activation in ovarian torsion-detorsion injury.

The aim of this study was to evaluate the role of vitamin E in follicular degeneration and to assess histopathological and biochemical changes following ischemia-reperfusion (IR) injury in rat ovaries. Twenty-eight Wistar albino rats were randomly divided into four groups: sham, 4h torsion, 24h detorsion, and a vitamin E group. Thirty minutes before detorsion, a single dose of 200mg/kg vitamin E was administered intraperitoneally. The ovarian histology score was determined, serum levels of malondialdehyde (MDA) and myeloperoxidase (MPO) were measured. The apoptosis of granulosa cells and the phospho-c-jun N-terminal kinase (p-JNK) and phospho-p38 (p-p38) immunoreactivities of these cells were determined. MDA and MPO levels were significantly increased in the torsion and detorsion groups. Hemorrhage, edema, and congestion were also apparent in these groups. In addition, the apoptotic index and the immunoreactivity of p-JNK were highest in the detorsion group, which also showed marked follicular degeneration. However, p-p38 activity was not affected by torsion-detorsion (TD) induction. Vitamin E ameliorated TD-induced histological alterations. It also decreased serum levels of MDA and MPO, reduced the activity of p-JNK in the ovaries, and reduced numbers of apoptotic follicular cells. In conclusion, these data indicate that vitamin E attenuated ovarian follicular degeneration by inhibiting the immunoreactivity of p-JNK and reducing the apoptosis of granulosa cells.

Effects of curcumin on apoptosis and oxidoinflammatory regulation in a rat model of acetic acid-induced colitis: the roles of c-Jun N-terminal kinase and p38 mitogen-activated protein kinase.

The present study evaluated the effects of curcumin on epithelial cell apoptosis, the immunoreactivity of the phospho-c-Jun N-terminal kinase (JNK) and phospho-p38 mitogen-activated protein kinases (MAPKs) in inflamed colon mucosa, and oxidative stress in a rat model of ulcerative colitis induced by acetic acid. Rats were randomly divided into three groups: control, acetic acid, and acetic acid+curcumin. Curcumin (100 mg/kg per day, intragastrically) was administered 10 days before the induction of colitis and was continued for two additional days. Acetic acid-induced colitis caused a significant increase in the macroscopic and microscopic tissue ranking scores as well as an elevation in colonic myeloperoxidase (MPO) activity, malondialdehyde (MDA) levels, and the number of apoptotic epithelial cells in colon tissue compared to controls. In the rat colon, immunoreactivity of phospho-p38 MAPK was increased, whereas the phospho-JNK activity was decreased following the induction of colitis. Curcumin treatment was associated with amelioration of macroscopic and microscopic colitis sores, decreased MPO activity, and decreased MDA levels in acetic acid-induced colitis. Furthermore, oral curcumin supplementation clearly prevented programmed cell death and restored immunreactivity of MAPKs in the colons of colitic rats. The results of this study suggest that oral curcumin treatment decreases colon injury and is associated with decreased inflammatory reactions, lipid peroxidation, apoptotic cell death, and modulating p38- and JNK-MAPK pathways.

Protection by L-carnitine against radiation-induced ileal mucosal injury in the rat: pattern of oxidative stress, apoptosis and cytokines.

PURPOSE: In this study, we tested the effects of L-carnitine (LC) on radiation-induced ileal mucosal damage. MATERIALS AND METHODS: Thirty Wistar albino rats were divided into five groups. The control group received physiological saline intraperitoneally (i.p.). Radiation-1 and radiation-2 groups received whole-body X-irradiation of 8.3 Gy as a single dose. These groups were sacrificed at the 6th hour and 4th day after irradiation, respectively. The Radiation-1 + LC and the radiation-2 + LC groups received the same dose irradiation plus a daily dose of 200 mg/kg LC. LC was applied one day before and for four days after irradiation. RESULTS: The levels of serum monocyte chemotactic protein-1 (MCP-1) and interferon gamma (IFN-γ) were significantly higher in the radiation groups when compared with the control. Treatment with LC decreased the serum MCP-1 and IFN-γ levels considerably. In the radiations groups, the Chiu score was significantly elevated compared with that of the control group. However, LC administered prior to the irradiation reduced the severity of mucosal damage. The number of apoptotic cells of the ileal crypt in the irradiated rats increased from the 6th hour after irradiation and then decreased at 4th day. CONCLUSIONS: Our data demonstrated that LC may be beneficial to radiation enteritis.

Role of amifostine on acute and late radiation nephrotoxicity: a histopathological study.

BACKGROUND: The present study was performed to determine the effect of amifostine in the prevention of radiation-induced acute and late period morphologic damages in rat kidney via light and electron microscopic examinations. MATERIALS AND METHODS: Control rats (n=6) received saline solution 30 min before sham irradiation; the radiotherapy alone group (n=12) received saline solution 30 min before irradiation (a single dose of 15 Gy, applied unilaterally to the kidney) and a final radiotherapy +amifostine group (n=12) received 200 mg/kg amifostine 30 min prior to irradiation. RESULTS: Microscopic examinations of irradiated kidneys revealed presence of glomerular tuft capsular adhesion, fusion of the foot processes and ballon-like cellular degeneration and loss of luminal brush border in tubules as early as eight weeks after irradiation. By 24 weeks post-irradiation, these changes were advanced and associated with focal mesangiolysis, segmental sclerosis and focal tubular atrophy. In addition, local irradiation caused interstitial fibrotic lesions in the kidney. Pretreatment of amifostine markedly prevented these glomerular and tubular changes, and interstitial fibrotic lesions. CONCLUSION: This study suggests that amifostine pretreatment may contribute to prevention of radiation-induced acute and late nephrotoxicity.

Protective effect of flaxseed oil on renal injury in hyperlipidaemic rats: the effect of flaxseed oil on hyperlipidaemia.

This study evaluated the possible effects of flaxseed oil on renal damage associated with hyperlipidaemic rats. Wistar albino male rats were divided into three groups. Group I was fed with a pellet chow. Group II was fed with a high cholesterol diet (HCD) consisting of 5% cholesterol and 0.35% cholic acid added to the pellet chow. Group III was fed with the same HCD, but were orally treated with a dose of 15 mg/kg body wt/day flaxseed oil. Flaxseed oil treatment started 1 week before and continued throughout the 22 weeks of the HCD. At the end of the experiment, renal tissue and blood samples were collected. The biochemical and histopathological findings confirmed renal damage in hypercholesterolaemia conditions. Flaxseed oil reduced the hypercholesterolaemia-induced increase in the serum levels of total cholesterol, LDL and urea. Oil red O stain revealed that lowered serum lipid was accompanied by a decreased deposition of neutral lipid. Flaxseed oil effectively reversed these abnormalities, verifying the protective effects of flaxseed oil in ameliorating renal injuries associated with hypercholesterolaemia.

Antiapoptotic effect of L-carnitine on testicular irradiation in rats.

We evaluated the effects of L-carnitine on apoptosis of germ cells in the rat testis following irradiation. Male Wistar rats were divided into three groups. Control group received sham irradiation plus physiological saline. Radiotherapy group received scrotal gamma-irradiation of 10 Gy as a single dose plus physiological saline. Radiotherapy + L-carnitine group received scrotal irradiation plus 200 mg/kg intraperitoneally L-carnitine. Twenty-four hours post-irradiation, the rats were sacrificed and testes were harvested. Testicular damage was examined by light and electron microscopy, and germ cell apoptosis was determined by terminal deoxynucleotidyltransferase-mediated deoxyuridine triphosphate in situ nick end-labeling (TUNEL) technique. Morphologically, examination of irradiated testis revealed presence of disorganization and desquamation of germinal cells and the reduction in sperm count in seminiferous tubule lumen. Under electron microscopy, the morphological signs of apoptosis were frequently detected in spermatogonia. Apoptotic spermatogonia showed the marginal condensation of chromatin onto the nuclear lamina, nucleus and cytoplasm shrinkage and still functioning cell organelles. TUNEL-positive cells were significantly more numerous in irradiated rats than in control rats. L-carnitine treatment significantly attenuated the radiation-induced morphological changes and germ cell apoptosis in the irradiated rat testis. In conclusion, these results suggested that L-carnitine supplementation during the radiotherapy may be beneficial for spermatogenesis following testicular irradiation by decreasing germ cell apoptosis.

Role of L-carnitine in the prevention of seminiferous tubules damage induced by gamma radiation: a light and electron microscopic study.

The present study, we hypothesized that L-carnitine can minimize germ-cell depletion and morphological features of late cell damage in the rat testis following gamma (gamma)-irradiation. Wistar albino male rats were divided into three groups. Control group received physiological saline 0.2 ml intraperitoneally (i.p.), as placebo. Radiation group received scrotal gamma-irradiation of 10 Gy as a single dose plus physiological saline. Radiation + L-carnitine group received scrotal gamma-irradiation plus 200 mg/kg i.p. L-carnitine. L-carnitine starting 1 day before irradiation and 21 days (three times per week) after irradiation. Testis samples of the all groups were taken at day 21, 44 and 70 post-irradiation. All samples were processed at the light and electron microscopic levels. Morphologically, examination of gamma-irradiated testis revealed presence of marked disorganization and depletion of germ cells, arrest of spermatogenesis, formation of multinucleated giant cells, and vacuolization in the germinal epithelium. The type and extent of these changes varied at different post-treatment intervals. The damage was evident at the 21st day and reached maximum level by the 44th day. By day 44 post-irradiation, the changes were most advanced, and were associated with atrophied seminiferous tubules without germ cells, the increase in the number and size of vacuolizations in germinal epithelium, and the absent multinucleated giant cells due to spermatids had completely disappeared. The increase in nucleus invaginations, the dilatation of smooth endoplasmic reticulum cysternas and the increase in the number and size of lipid droplets in the Sertoli cells were determined at the electron microscopic level. In conclusion, L-carnitine supplementation during the radiotherapy would be effective in protecting against radiation-induced damages in rat testis, and thereby may improve the quality of patient's life after the therapy.