The Effect of Ellagic Acid on Intra-abdominal Adhesions Caused by Gallstones.

BACKGROUND: Adhesion formation after peritoneal surgery is the main cause of postoperative bowel obstruction, infertility, and chronic pelvic pain. In this study, we evaluated the effect of oral ellagic acid on intra-abdominal adhesions caused by gallstones in rats. MATERIALS AND METHODS: Forty-one Wistar-albino rats were used. Gallstones were dropped to the right lower quadrant of the abdomen to create adhesions. They were divided into 4 groups; sham-operated, intraperitoneal gallstone, oral ellagic acid (control), and intraperitoneal gallstone+oral ellagic acid. On the postoperative 10th day, relaparotomy was performed, adhesions were evaluated according to four different macroscopic adhesion score systems and adhesion-bearing tissues were examined histopathologically. Samples were graded for inflammation, vascularization, and fibrosis. RESULTS: We found that oral administration of ellagic acid lowered all macroscopic adhesion scores. There were significant differences between groups of sham and gallstone; control and gallstone; control and gallstone+oral ellagic acid (P<0.05). CONCLUSION: The ellagic acid administered orally at a dose of 100 mg/kg/d significantly inhibited intra-abdominal adhesion formation and no adverse effects were seen between treatments.

Inhibition of neutral sphingomyelinase decreases elevated levels of nitrative and oxidative stress markers in liver ischemia-reperfusion injury.

Oxidative stress and excessive nitric oxide production via induction of inducible nitric oxide synthase (NOS)-2 have been shown in the pathogenesis of liver ischemia-reperfusion (IR) injury. Neutral sphingomyelinase (N-SMase)/ceramide pathway can regulate NOS2 expression therefore this study determined the role of selective N-SMase inhibition on nitrative and oxidative stress markers following liver IR injury. Selective N-SMase inhibitor was administered via intraperitoneal injections. Liver IR injury was created by clamping blood vessels supplying the median and left lateral hepatic lobes for 60 min, followed by 60 min reperfusion. Nitrative and oxidative stress markers were determined by evaluating NOS2 expression, protein nitration, nitrite/nitrate levels, 4-hydroxynonenal (HNE) formation, protein carbonyl levels and xanthine oxidase/xanthine dehydrogenase (XO/XDH) activity. Levels of sphingmyelin and ceramide in liver tissue were determined by an optimized multiple reaction monitoring method using ultra-fast liquid chromatography coupled with tandem mass spectrometry (MS/MS). Spingomyelin levels were significantly increased in all IR groups compared to controls. Treatment with a specific N-SMase inhibitor significantly decreased all measured ceramides in IR injury. NOS2 expression, nitrite/nitrate levels and protein nitration were significantly greater in IR injury and decreased with N-SMase inhibition. Treatment with a selective N-SMase inhibitor significantly decreased HNE formation, protein carbonyl levels and the hepatic conversion of XO. Data confirm the role of nitrative and oxidative injury in IR and highlight the protective effect of selective N-SMase inhibition. Future studies evaluating agents blocking N-SMase activity can facilitate the development of treatment strategies to alleviate oxidative injury in liver I/R injury.

Neutral sphingomyelinase inhibition alleviates apoptosis, but not ER stress, in liver ischemia-reperfusion injury.

Previous studies have revealed the activation of neutral sphingomyelinase (N-SMase)/ceramide pathway in hepatic tissue following warm liver ischemia reperfusion (IR) injury. Excessive ceramide accumulation is known to potentiate apoptotic stimuli and a link between apoptosis and endoplasmic reticulum (ER) stress has been established in hepatic IR injury. Thus, this study determined the role of selective N-SMase inhibition on ER stress and apoptotic markers in a rat model of liver IR injury. Selective N-SMase inhibitor was administered via intraperitoneal injections. Liver IR injury was created by clamping blood vessels supplying the median and left lateral hepatic lobes for 60 min, followed by 60 min reperfusion. Levels of sphingmyelin and ceramide in liver tissue were determined by an optimized multiple reactions monitoring (MRM) method using ultrafast-liquid chromatography (UFLC) coupled with tandem mass spectrometry (MS/MS). Spingomyelin levels were significantly increased in all IR groups compared with controls. Treatment with a specific N-SMase inhibitor significantly decreased all measured ceramides in IR injury. A significant increase was observed in ER stress markers C/EBP-homologous protein (CHOP) and 78 kDa glucose-regulated protein (GRP78) in IR injury, which was not significantly altered by N-SMase inhibition. Inhibition of N-SMase caused a significant reduction in phospho-NF-kB levels, hepatic TUNEL staining, cytosolic cytochrome c, and caspase-3, -8, and -9 activities which were significantly increased in IR injury. Data herein confirm the role of ceramide in increased apoptotic cell death and highlight the protective effect of N-SMase inhibition in down-regulation of apoptotic stimuli responses occurring in hepatic IR injury.

Analysis of polyunsaturated fatty acids and the omega-6 inflammatory pathway in hepatic ischemia/re-perfusion injury.

The aim of the present study was to assess omega-3 (n-3) and omega-6 (n-6) polyunsaturated fatty acids (PUFAs) in liver tissue and evaluate changes in the n­6-associated inflammatory pathway following liver ischemia/re­perfusion (IR) injury. Male Wistar rats which were allowed free access to standard rat chow were included in the study. Blood vessels supplying the median and left lateral hepatic lobes were occluded with an arterial clamp for 60 min, followed by 60 min of re­perfusion. Levels of arachidonic acid (AA, C20:4n­6), dihomo­gamma­linolenic acid (DGLA, C20:3n­6), eicosapentaenoic acid (EPA, C20:5n­3) and docosahexaenoic acid (DHA, C22:6n­3) in liver tissue were determined by an optimized multiple reaction monitoring method using ultra fast­liquid chromatography coupled with tandem mass spectrometry. Phospholipase A2 (PLA2), cyclooxygenase (COX) and prostaglandin E2 (PGE2) were measured in tissue samples to evaluate changes in the n­6 inflammatory pathway. Total histopathological score of cellular damage were significantly increased following hepatic IR injury. n­3 and n­6 PUFA levels were significantly increased in post­ischemic liver tissue compared to those in non­ischemic controls. No significant difference was observed in the AA/DHA and AA/EPA ratio in post­ischemic liver tissues compared with that in the control. Tissue activity of PLA2 and COX as well as PGE2 levels were significantly increased in post­ischemic liver tissues compared to those in non­ischemic controls. The results of the present study suggested that increased hydrolysis of fatty acids via PLA2 triggers the activity of COX and leads to increased PGE2 levels. Future studies evaluating agents which block the formation of eicosanoids derived from n­6 PUFAs may facilitate the development and application of treatment strategies in liver injury following IR.

Inhibition of neutral sphingomyelinase decreases arachidonic acid mediated inflammation in liver ischemia-reperfusion injury.

This study aimed to determine the role of selective neutral sphingomyelinase (N-SMase) inhibition on arachidonic acid (AA) mediated inflammation following liver ischemia-reperfusion (IR) injury. Selective N-SMase inhibitor was administered via intraperitoneal injections. Liver IR injury was created by clamping blood vessels supplying the median and left lateral hepatic lobes for 60 min, followed by 60 min reperfusion. Levels of AA in liver tissue were determined by multiple reaction monitoring (MRM) using ultra fast-liquid chromatography (UFLC) coupled with tandem mass spectrometry (MS/MS). Phospholipase A2 (PLA2), cyclooxygenase (COX) and prostaglandin E2 (PGE2) were measured in liver tissue. Arachidonic acid levels, activity of PLA2, COX and PGE2 levels were significantly increased in postischemic liver tissue compared to nonischemic controls. N-SMase inhibition significantly decreased COX activity and PGE2 levels in postischemic liver. Future studies evaluating agents blocking N-SMase activity can facilitate the development of treatment strategies to alleviate inflammation in liver I/R injury.

Effect of doxazosin on expression of eNOS in rat kidney in the presence of partial bladder outlet obstruction.

BACKGROUND: The role of nitric oxide in the pathogenesis of renal injury has begun to be appreciated. We therefore designed this study to demonstrate the relationship between endothelial nitric oxide synthase (eNOS) expression and doxazosin in the kidneys of rats with surgically created partial bladder outlet obstruction (BOO), to further understand the role of doxazosin in the prevention of renal parenchymal damage by partial BOO. MATERIAL AND METHODS: A total of 35 adult female Wistar rats, mean weight 250 g, were randomly allocated to 3 experimental groups: group1, sham-operated (n=10); group 2, partial BOO group (n=14) and group 3, partial BOO group treated with doxazosin (n=11). Partial BOO in rats was surgically induced. Results were assessed by eNOS immunohistochemistry. RESULTS: eNOS staining in kidneys in group 1 (16.45 ± 1.63) was significantly higher than in group 2 (5.09 ± 0.61) (p<0.05). After 15 days of doxazosin treatment in addition to partial BOO (group 3), eNOS staining in the kidney (11.80 ± 1.63) was significantly higher than in group 2 (5.09 ± 0.61) (p<0.05). In samples taken after 15 days of doxazosin treatment in addition to partial BOO, eNOS staining in kidneys (11.80 ± 1.63) was lower than in the sham-operated group (16.45 ± 1.63), but the difference was not significant (p>0.05). CONCLUSION: These findings may provide insight into the beneficial and restorative effects of α(1)-adrenoceptor antagonists on eNOS expression in the kidney, when used to treat symptoms of benign prostate hyperplasia and hypertension.

Effect of astaxanthin on hepatocellular injury following ischemia/reperfusion.

This study investigated the effect of astaxanthin (ASX; 3,3-dihydroxybeta, beta-carotene-4,4-dione), a water-dispersible synthetic carotenoid, on liver ischemia-reperfusion (IR) injury. Astaxanthin (5 mg/kg/day) or olive oil was administered to rats via intragastric intubation for 14 consecutive days before the induction of hepatic IR. On the 15th day, blood vessels supplying the median and left lateral hepatic lobes were occluded with an arterial clamp for 60 min, followed by 60 min reperfusion. At the end of the experimental period, blood samples were obtained from the right ventricule to determine plasma alanine aminotransferase (ALT) and xanthine oxidase (XO) activities and animals were sacrificed to obtain samples of nonischemic and postischemic liver tissue. The effects of ASX on IR injury were evaluated by assessing hepatic ultrastructure via transmission electron microscopy and by histopathological scoring. Hepatic conversion of xanthine dehygrogenase (XDH) to XO, total GSH and protein carbonyl levels were also measured as markers of oxidative stress. Expression of NOS2 was determined by immunohistochemistry and Western blot analysis while nitrate/nitrite levels were measured via spectral analysis. Total histopathological scoring of cellular damage was significantly decreased in hepatic IR injury following ASX treatment. Electron microscopy of postischemic tissue demonstrated parenchymal cell damage, swelling of mitochondria, disarrangement of rough endoplasmatic reticulum which was also partially reduced by ASX treatment. Astaxanthine treatment significantly decreased hepatic conversion of XDH to XO and tissue protein carbonyl levels following IR injury. The current results suggest that the mechanisms of action by which ASX reduces IR damage may include antioxidant protection against oxidative injury.