Cornus mas L. Extract Targets the Specific Molecules of the Th17/Treg Developmental Pathway in TNBS-Induced Experimental Colitis in Rats.

Given that one of the crucial events in the pathogenesis of inflammatory bowel disease is the loss of homeostasis between Th17 and Treg cells, targeting the specific molecules of the Th17/Treg axis developmental pathway is a promising strategy for inflammatory bowel disease prevention and treatment. The current study aimed to assess the impact of cornelian cherry (Cornus mas L.) extract, rich in iridoids and polyphenols known for their potential anti-inflammatory activity, at two doses (20 or 100 mg/kg) on the crucial factors for Th17/Treg cell differentiation in the course of experimental colitis and compare this action with that of sulfasalazine. This study was conducted on the biobank colon tissue samples collected during the previous original experiment, in which colitis in rats was induced by trinitrobenzenesulfonic acid (TNBS). The levels of IL-6, RORγt, total STAT3, p-STAT3, and Foxp3 were determined by ELISA. The expression of PIAS3 mRNA was quantified by qPCR. Cornelian cherry extract at a dose of 100 mg/kg counteracted the TNBS-induced elevation of IL-6, RORγt, and p-STAT3 levels and a decrease in Foxp3 level and PIAS3 mRNA expression, while given concomitantly with sulfasalazine was more effective than sulfasalazine alone in reversing the TNBS-induced changes in IL-6, RORγt, total STAT3, p-STAT3, Foxp3 levels, and PIAS3 mRNA expression. The beneficial effect of cornelian cherry extract on experimental colitis may be due to its immunomodulatory activity reflected by the influence on factors regulating the Th17/Treg axis.

Targeting Lineage-Specific Transcription Factors and Cytokines of the Th17/Treg Axis by Novel 1,3,4-Oxadiazole Derivatives of Pyrrolo[3,4-d]pyridazinone Attenuates TNBS-Induced Experimental Colitis.

The pharmacotherapy of inflammatory bowel disease (IBD) is still not fully effective and safe. Attempts to search for new IBD drugs remain an incessant research aim. One of the novel approaches is targeting the developmental pathway molecules and effector cytokines of Th17/Treg axis. This study aimed to elucidate the impact of new pyrrolo[3,4-d]pyridazinone derivatives, compounds 7b, 10b, or 13b, on the course of experimental colitis in rats and to assess whether these new compounds may influence Th17/Treg axis. Rats were pretreated with studied compounds intragastrically before intrarectal administration of 2,4,6-trinitrobenzenesulfonic acid used for colitis induction. Body weight loss, disease activity index, colon index, and colon tissue damage were analyzed to evaluate the severity of colitis. The colonic levels of RORγt, STAT3, CCR6, Foxp3, IL-6, IL-10, IL-17, TNF-α, IL-23, and PGE2 were assessed. Pretreatment with compounds 7b and 13b alleviated the severity of colitis and concomitantly counteracted the increased levels of RORγt, STAT3, CCR6, IL-6, IL-17, IL-23, TNF-α, and PGE2. The beneficial effect of compounds 7b and 13b may be due to the decrease in the levels of Th17-specific transcription factors and cytokines. The studied compounds might therefore constitute a promising therapeutic strategy in Th17/Treg imbalance-driven inflammatory conditions such as IBD.

Effect of a Low Dose of Carvedilol on Cyclophosphamide-Induced Urinary Toxicity in Rats-A Comparison with Mesna.

One of the major side effects of cyclophosphamide (CPX)-an alkylating anticancer drug that is still clinically used-is urotoxicity with hemorrhagic cystitis. The present study was designed to evaluate the ability of carvedilol to protect rats from cyclophosphamide-induced urotoxicity. Rats were injected intraperitoneally (i.p.) with CPX (200 mg/kg) and administered carvedilol (2 mg/kg) intragastrically a day before, at the day and a day after a single i.p. injection of CPX, with or without mesna (40, 80, and 80 mg/kg i.p. 20 min before, 4 h and 8 h after CPX administration, respectively). Pretreatment with carvedilol partly prevented the CPX-induced increase in urinary bladder and kidney index, and completely protects from CPX-evoked alterations in serum potassium and creatinine level, but did not prevent histological alterations in the urinary bladder and hematuria. However, carvedilol administration resulted in significant restoration of kidney glutathione (GSH) level and a decrease in kidney interleukin 1ß (IL-1ß) and plasma asymmetric dimethylarginine (ADMA) concentrations. Not only did mesna improve kidney function, but it also completely reversed histological abnormalities in bladders and prevented hematuria. In most cases, no significant interaction of carvedilol with mesna was observed, although the effect of both drugs together was better than mesna given alone regarding plasma ADMA level and kidney IL-1ß concentration. In conclusion, carvedilol did not counteract the injury caused in the urinary bladders but restored kidney function, presumably via its antioxidant and anti-inflammatory properties.

Novel 1,3,4-Oxadiazole Derivatives of Pyrrolo[3,4-d]Pyridazinone Exert Anti-Inflammatory Activity without Acute Gastrotoxicity in the Carrageenan-Induced Rat Paw Edema Test.

BACKGROUND AND PURPOSE: Due to the risk of gastrointestinal damage and various tissue toxicity associated with non-steroidal anti-inflammatory drugs (NSAIDs) use, investigating new anti-inflammatory agents with efficacy comparable to that of NSAIDs but reduced toxicity is still a major challenge and a clinical need. Based on our previous study, new 1,3,4-oxadiazole derivatives of pyrrolo[3,4-d]pyridazinone, especially 6-butyl-3,5,7-trimethyl-1-[[4-[[4-(4-nitrophenyl)piperazin-1-yl]methyl]-5-thioxo-1,3,4-oxadiazol-2-yl]methoxy]pyrrolo[3,4-d]pyridazin-4-one and 6-butyl-1-[[4-[[4-(4-chlorophenyl)-4-hydroxy-1-piperidyl]methyl]-2-thioxo-1,3,4-oxadiazol-5-yl]methoxy]-3,5,7-trimethyl-pyrrolo[3,4-d]pyridazin-4-one (hereafter referred to as the compounds 10b and 13b, respectively) seem to be promising anti-inflammatory agents. This study aimed to elucidate the effects of these two new derivatives on the course of experimental rat inflammation, liver and kidney function, and gastric mucosa. METHODS: The anti-inflammatory effect of compounds 10b and 13b was evaluated using the carrageenan-induced paw edema test in rats. The increase in paw volume (paw edema), prostaglandin E2 (PGE2), tumor necrosis factor-α (TNF-α) and myeloperoxidase (MPO) levels, histological alterations, and inflammatory cell infiltration in paw tissue were determined. Serum alanine transaminase (ALT) and aspartate transaminase (AST) activities, serum urea and creatinine levels, as well as changes in gastric mucosa, were measured as indicators of hepatic, renal, and gastric toxicity. RESULTS: Pretreatment with both novel derivatives at 10 mg/kg and 20 mg/kg doses reduced paw edema, counteracted the increased PGE2 and TNF-α levels, reduced the influx of inflammatory cells, and decreased histopathological alterations in paw tissue. Compound 13b at a dose of 20 mg/kg was more effective than indomethacin in reversing the increased TNF-α levels and reducing the influx of inflammatory cells. Only compound 13b at all studied doses (5, 10, or 20 mg/kg) counteracted the increased MPO level in paw tissue. Both compounds neither caused alterations in ALT, AST, urea, creatinine parameters nor gastric mucosal lesions. CONCLUSION: New compounds exert an anti-inflammatory effect, presumably via inhibiting inflammatory mediators release and inflammatory cell infiltration. Moreover, both possess a more favorable benefit-risk profile than indomethacin, especially compound 13b.

Long-Term Administration of Abacavir and Etravirine Impairs Semen Quality and Alters Redox System and Bone Metabolism in Growing Male Wistar Rats.

Highly active antiretroviral therapy (HAART) is used in HIV-infected patients. Alongside the prolongation of patients' life, adverse side effects associated with long-term therapy are becoming an increasing problem. Therefore, optimizing of HAART is extremely important. The study is aimed at evaluating the toxicity of abacavir and etravirine in monotherapy on the reproductive system, liver, kidneys, and bones in young, sexually mature, male rats. Thirty-six 8-week-old male Wistar rats randomized into three 12-animal groups received either normal saline (control), abacavir 60 mg/kg (AB group), or etravirine 40 mg/kg (ET group) once daily for 16 weeks. Semen morphology, oxide-redox state parameters (MDA, SOD, catalase, GPx, glutathione, GSH/GSSG ratio) in tissue homogenates (testes, liver, kidneys), and serum samples were studied. In bones, microcomputed tomography and a four-point bending test were performed. Total sperm count, sperm concentration, motility, and sperm morphology did not differ significantly in AB or ET groups compared to the control. In the flow cytometry of semen, an increased percentage of cells with denatured DNA was noticed for both tested drugs. However, no significant changes of oxide-redox state in testicular homogenates were found, except of increased SOD activity in the AB-receiving group. Additionally, ET significantly altered catalase and GPx in the liver and SOD activity in kidneys. Abacavir decreased catalase in the liver and GSH levels in kidneys. AB caused significant changes to bone microarchitecture (bone volume fraction, trabecular number, connectivity density, total porosity) and increased Young's modulus. Etravirine had a greater impact on macrometric parameters of bones (tibial index, mid-tibial diameter, femur length). After 4 weeks in the ET group, a lower 1,25-dihydroxyvitamin D3 serum concentration was found. The results showed that abacavir and etravirine disturb oxidative stress. An increase in the percentage of sperms with chromatin damage suggests decreased fertility in rats receiving the studied drugs. Both drugs affected bone formation in growing rats. Additionally, etravirine disturbed vitamin D metabolism.

Cornelian Cherry Iridoid-Polyphenolic Extract Improves Mucosal Epithelial Barrier Integrity in Rat Experimental Colitis and Exerts Antimicrobial and Antiadhesive Activities In Vitro.

BACKGROUND AND AIMS: Inflammatory bowel disease pharmacotherapy, despite substantial progress, is still not satisfactory for both patients and clinicians. In view of the chronic and relapsing disease course and not always effective treatment with adverse effects, attempts to search for new, more efficient, and safer substances are essential and reasonable. This study was designed to elucidate the impact of cornelian cherry iridoid-polyphenolic extract (CE) and loganic acid (LA) on adherent-invasive E. coli growth and adhesion in vitro and to assess the effect of pretreatment with CE or LA on the course of intestinal inflammation in rat experimental colitis compared with sulfasalazine. METHODS: Antibacterial and antiadhesive activities of CE and LA were assessed using microdilution, Int407 cell adherence, and yeast agglutination assays. The colitis model was induced by 2,4,6-trinitrobenzenesulfonic acid. Studied substances were administered intragastrically for 16 days prior to colitis induction. Body weight loss; colon index; histological injuries; IL-23, IL-17, TNF-α, and chemerin levels; and STAT3, Muc2, and TFF3 mRNA expression were evaluated. RESULTS: Only CE exerted antimicrobial and antiadhesive activities in vitro and alleviated colonic symptoms. CE coadministrated with sulfasalazine was more effective than single compounds in reversing increased concentrations of TNF-α, IL-17, and chemerin and decreased Muc2 mRNA expression. CONCLUSIONS: CE exerted a protective effect against experimental colitis via impaired mucosal epithelial barrier restoration and intestinal inflammatory response attenuation and given concomitantly with sulfasalazine counteracted colitis in a more effective way than sulfasalazine alone, which indicates their synergistic interaction. The beneficial effect of CE may also be due to its bacteriostatic and antiadhesive activities.

The impact of sitagliptin, inhibitor of dipeptidyl peptidase-4 (DPP-4), on the ADMA-DDAH-NO pathway in ischemic and reperfused rat livers.

BACKGROUND: A correlation between the level of asymmetric dimethylarginine (ADMA) - the inhibitor of the nitric oxide (NO) synthesis - and the liver function and survival after a liver transplantation has been reported. OBJECTIVES: The aim of this study was to evaluate the effect of sitagliptin -the inhibitor of dipeptidyl peptidase-4 (DPP-4) - on the NO-ADMA-dimethylarginine dimethylaminohydrolase (DDAH) pathway in rat livers subjected to ischemia/reperfusion (IR). MATERIAL AND METHODS: The rats received sitagliptin (5 mg/kg, per os - p.o.) (groups: S - livers not subjected to IR procedure, and SIR - livers subjected to IR procedure) or a saline solution (groups: C - livers not subjected to IR procedure, and CIR - livers subjected to IR procedure) for 14 days; following this, livers in the SIR and CIR groups were subjected to ischemia (60 min) and reperfusion (24 h). Aminotransferases were measured before the surgery; additionally, the arginine (ARG), ADMA and symmetric dimethylarginine (SDMA) levels were estimated just before ischemia and during reperfusion (at 0.5, 4 and 24 h). After IR, citrulline, the DDAH activity, mRNA for type 1 DDAH (DDAH1), and arginine methyltransferase type 1 (PRMT1) were determined. RESULTS: The increase in the initial level of ARG/ADMA0 (A/A) ratio in group S compared to group C verged on statistical significance. At 0.5 and 4 h of reperfusion, the highest concentration of ADMA was found in group CIR. At those time points, the ARG level and the A/A ratio were decreased in groups CIR and SIR as compared to groups C and S, respectively. The alanine transaminase (ALT) activity was lower in the sitagliptin-treated group than in the non-treated one. The DDAH and citrulline levels were reduced in group CIR as compared to group C, but were greater in group SIR as compared to group S. The PRMT1 mRNA expression was higher in groups CIR and SIR, compared to groups C and S, respectively. CONCLUSIONS: The increased A/A ratio suggests a protective effect of sitagliptin on livers not subjected to IR. Changes in the DDAH activity and the PRMT1 mRNA expression also imply the protective activity of sitagliptin during IR.

Age-related differences in function and structure of rat livers subjected to ischemia/reperfusion.

INTRODUCTION: Liver function is affected during ischemia/reperfusion (IR). The current state of knowledge about liver aging processes during IR is incomplete. We evaluated the effects of aging on liver structure and function under IR conditions. MATERIAL AND METHODS: Animals were divided into control (C-2) and ischemia/reperfusion (IR-2) groups of young rats (2-4 months old) and C-12 and IR-12 groups of old rats (12-14 months old). The livers from IR-2 and IR-12 groups were subjected to partial ischemia (60 min), followed by global reperfusion (4 h). Blood samples were obtained during reperfusion (0, 30 and 240 min) to estimate the activity of aminotransferases (ALT, AST). After IR, tumor necrosis factor-α (TNF-α), interleukin-1b (IL-1b), malondialdehyde (MDA), and superoxide dismutase (SOD) were determined in liver homogenates. RESULTS: At all points of reperfusion, an increase in aminotransferase activity levels in the ischemic groups was observed; mainly between IR-12 and C-12 rats. The concentration of TNF-α was significantly higher in young animals (in non-ischemic groups: p = 0.09, in ischemic groups: p = 0.05). Under IR conditions, the concentration of IL-1b dropped (p = 0.05). The concentration of MDA was significantly higher in mature animals (in non-ischemic groups: p = 0.09, in ischemic groups: p = 0.05). In ischemic groups an increase in necrosis rate was observed regardless of age. Rats in the IR-12 group showed the most pronounced changes in hepatic architecture, including increased micro- and macrosteatosis and parenchymal cell destruction. CONCLUSIONS: The function and structure of mature livers slightly deteriorate with age and these differences are more noticeable under IR conditions.

The impact of mangiferin from Belamcanda chinensis on experimental colitis in rats.

BACKGROUND: Inflammatory bowel disease (IBD) [including Crohn's disease (CD) and ulcerative colitis (UC)] constitutes an important clinical problem. The pathogenesis of IBD remains unclear. It is believed that immune dysfunction, inflammatory mediators and oxidative damage play crucial roles in development of IBD. The condition is clinically associated with symptoms ranging from mild to severe during relapses, depending on the affected segment of the gastrointestinal tract. Bloody diarrhea with mucus, abdominal pain, weight loss and anemia are initial symptoms of both CD and UC. Differences between diseases become more evident in time, along with the development of intestinal and extraintestinal complications. Mangiferin (1,3,6,7-tetrahydroxyxanthone-C-2-ß-D-glucoside), a natural polyphenol in plants, exerts antioxidant and anti-inflammatory effects making it an interesting option for the treatment of inflammatory pathologies associated with oxidative stress in humans, such as IBD. PURPOSE: The aim of the current study was to elucidate the impact of mangiferin on colon tissues in 2,4,6-trinitrobenzensulfonic acid (TNBS)-induced colitis in rats. METHODS: Mangiferin was obtained from Belamcanda chinensis rhizomes by a multistage process. Groups of rats were pre-treated with 10, 30 or 100 mg/kg of mangiferin, or with distilled water administered intragastrically for 16 days. An ethanol solution of TNBS or saline was given rectally on the day 15 of the experiment. The experiment was terminated on the day 17. The colon was removed, cleaned, weighed and examined macro- and microscopically. Determination of tumor necrosis factor α (TNF-α), interleukin 17 (IL-17), malondialdehyde (MDA) levels and superoxide dismutase (SOD) activity were performed spectrophotometrically in homogenates of colon tissues. RESULTS: Rats in the TNBS group developed symptoms of colitis, including: body weight loss, colon mass index increase and damage of intestinal tissues with concomitant increase in TNF-α, IL-17, MDA levels and decreased SOD activity. In non-TNBS-treated rats mangiferin did not cause any changes of studied parameters. Pre-treatment with mangiferin exerted a protective effect, reducing the intensity of damage caused by TNBS. Mangiferin at the doses of 30 and 100 mg/kg reduced the macro- and microscopic damage score and the MDA level in colon tissues. Only at the dose of 100 mg/kg, mangiferin decreased TNF-α and IL-17 concentrations, and SOD activity in colon tissues. CONCLUSION: Mangiferin attenuates inflammatory changes of colon tissues in experimental, TNBS-induced colitis in rats. Protective effect exerted by mangiferin depends primarily on its anti-inflammatory activity and secondarily on its antioxidant properties.

Oral administration of kaempferol inhibits bone loss in rat model of ovariectomy-induced osteopenia.

BACKGROUND: Postmenopausal osteoporosis and osteoporotic fractures constitute an increasing problem in developing countries. Kaempferol, isolated from seeds of Cuscuta chinensis, is an active flavonoid inhibiting in vitro osteoclast activity. The aim of the presented research was an assessment of kaempferol effect on estrogen-deficiency-induced bone structure disturbances in rats. METHODS: The study was performed on 24 Wistar female rats divided into 3 groups: SHAM - rats undergoing a "sham" surgery, OVX-C - control group of animals that underwent ovariectomy, OVX-K - rats undergoing ovariectomy and receiving kaempferol for 8 weeks (from day 56 to day 112). RESULTS: In the OVX-K group, contrary to the OVX-C one, there was no significant decrease in femoral bone mineral density (BMD). A significant increase in Young's modulus was observed in the OVX-K group compared to the OVX-C (15.33±2.51GPa vs. 11.14±1.93GPa, p<0.05). A decreased bone turnover was detected in the OVX-K group. Tissue volume ratio (BV/TV) and trabecular bone perimeter were increased in the OVX-K group compared to the OVX-C one (0.241±0.037 vs. 0.170±0.022, p<0.05 and 15.52±2.78mm vs. 9.67±3.07mm, p<0.05, respectively). CONCLUSION: Kaempferol has a beneficial influence on estrogen-deficiency-induced disturbances of bone structure in rats.

Iridoid-loganic acid versus anthocyanins from the Cornus mas fruits (cornelian cherry): Common and different effects on diet-induced atherosclerosis, PPARs expression and inflammation.

BACKGROUND AND AIMS: Cardiovascular benefits of fruits are attributed mainly to their (poly)phenolic constituents, especially anthocyanins. The main aim of our study is to compare effects of iridoids and anthocyanins from one fruit on diet-induced atherosclerosis. The cornelian cherry is a native or cultivated plant that grows in many European countries, used in cuisine and folk medicine. In our previous study, we showed its constituents and proved that oral administration of lyophilized fruits to hypercholesterolemic rabbits had preventive effects on atherosclerosis through the activation of PPARα expression. In this study, we have compared the effects of the main constituents of the cornelian cherry:iridoid loganic acid and anthocyanins. METHODS: Our experiment followed the model used in our previous study, in which rabbits were fed 1% cholesterol. RESULTS: We showed that both loganic acid (20 mg/kg b.w.) and a mixture of anthocyanins (10 mg/kg b.w.) administered orally for 60 days had a positive impact on dyslipidemia caused by cholesterol-rich diet, although the effects of anthocyanins were more pronounced. Anthocyanins decreased total and LDL-cholesterol and triglycerides and increased HDL-cholesterol. Loganic acid showed similar effects, but only the triglycerides and HDL-cholesterol changes achieved statistical significance. Anthocyanins, and to a lesser extent loganic acid, significantly decreased intima thickness and intima/media ratio in the thoracic aorta. Both substances decrease ox-LDL in the plasma. Anthocyanins significantly increased expression of PPARγ and α in the liver. Loganic acid also increased their expression, but to a lesser extent. Conversely, loganic acid showed pronounced anti-inflammatory effects, decreasing TNF-α and IL-6 activity. CONCLUSIONS: Our results imply that both substances have a positive effect on factors contributing to the development of diet-induced atherosclerosis. Our results also indicate the potential health benefits of fruits containing anthocyanins and iridoids, and support the idea of creating composed phytopharmaceuticals containing both groups of substances.

Impact of morin-5'-sulfonic acid sodium salt on cyclophosphamide-induced gastrointestinal toxicity in rats.

BACKGROUND: The aim of this study was to evaluate the effect of morin-5'-sulfonic acid sodium salt (NaMSA) on cyclophosphamide-induced gastrointestinal changes in rats. METHODS: Rats received intragastrically 0.9% saline (group C), cyclophosphamide (15 mg/kg) (group CX), NaMSA (100 mg/kg) (group M) or cyclophosphamide (15 mg/kg) with NaMSA (100 mg/kg) (group M-CX), respectively, for 10 days. RESULTS: No histological lesions were observed in the liver and the large intestine in the control group and group receiving NaMSA. In the cyclophosphamide-treated group, a generalized blurred trabecular structure, hepatocyte apoptosis, focal and diffuse necrosis were noticed in the liver and atypia of epithelial cells or adenoma were noticed in the large intestine. In the group receiving both cyclophosphamide and NaMSA, hepatocyte apoptosis in the liver was observed less frequently. Histological examination of the small intestine revealed: low-grade dysplasia adenoma in the C, M, CX and M-CX group (in 44%, 0%, 100%, and 55.6% of specimens, respectively) with adenocarcinoma in 55.6% of specimens in the cyclophosphamide-receiving group only. Adenoma with high-grade dysplasia was observed in the control and NaMSA-receiving group with a similar frequency (22%). In addition to the histological evaluation, blood cell count parameters, as well as total protein concentration, blood glucose level, amylase, ALT, AST and GGTP activities were evaluated. Cyclophosphamide impaired weight gain, decreased blood cell count parameters and total protein concentration, and increased the GGTP activity. Those changes were not reversed by NaMSA. CONCLUSIONS: Summing up, NaMSA may protect against some cyclophosphamide-induced histological abnormalities in the gastrointestinal tract, including intestinal neoplasia in rats.

The impact of morin, a natural flavonoid, on cyclophosphamide-induced changes in the oxidative stress parameters in rat livers.

BACKGROUND: Cyclophosphamide (CPX) has many adverse effects, partly due to oxidative stress induction in various tissues. Morin is one of the natural flavonoids with strong antioxidant properties. OBJECTIVES: The aim of the current research was to estimate the influence of morin on changes in antioxidant parameters in rat livers after cyclophosphamide administration. MATERIAL AND METHODS: The study was performed on Wistar rats. The rats in Group C received 0.9% saline; those in Group CX received cyclophosphamide (CPX); and those in Group M-CX received CPX with morin. Cyclophosphamide and morin were given by gastric gavage for 10 consecutive days at doses of 15 mg/kg and 100 mg/kg, respectively. Malondialdehyde (MDA) and glutathione (GSH) concentrations, superoxide dismutase (SOD) activity and catalase (CAT) activity were determined in liver tissue homogenates. RESULTS: CPX caused a significant decrease in SOD activity and GSH levels, but only the latter was fully restored by morin. There were no significant differences in CAT activity in the various groups. CPX also insignificantly decreased MDA levels, which was aggravated by co-administration of morin. CONCLUSIONS: The results obtained indicate that morin may exert some protective action on CPX-induced changes in the antioxidant state in rat livers.

Age-related changes in ADMA-DDAH-NO pathway in rat liver subjected to partial ischemia followed by global reperfusion.

BACKGROUND: Liver function is affected during ischemia/reperfusion (IR). We evaluated the effect of the aging process on selected parameters determining the NO level in rat liver subjected to IR. METHODS: The animals were divided into the C-2 and the IR-2 group of young rats (2-4 months old) and the C-12 and the IR-12 group of older rats (12-14 months old). Livers belonging to the IR-2 and the IR-12 group were subjected to partial ischemia (60 min) and reperfusion (4 h). Blood samples were obtained after surgeries to estimate the activity of aminotransferases, as well as just before ischemia and during reperfusion (15, 120, and 240 min) to estimate concentration of arginine (Arg) and its derivatives: asymmetric and symmetric dimethylarginine (ADMA, SDMA). After IR, dimethylarginine dimethylaminohydrolase (DDAH) activity and protein concentration of inducible nitric oxide synthase (iNOS) were measured in liver homogenates. RESULTS: In the IR-2 group ADMA level increased the most between 15 and 120 min of reperfusion and was the highest of all the groups (0.72±0.2 µmol/l). In the IR-12 group ADMA level decreased significantly and was lower compared to all the other groups at 15 min (0.42±0.2 µmol/l) and to IR-2 at 120 (0.52±0.1 µmol/l) and 240 min (0.38±0.1 µmol/l) of reperfusion. Only the IR-2 group SDMA level increased significantly between 15 (0.75±0.9 µmol/l) and 240 min (1.0±1.2 µmol/l) of reperfusion. At the beginning of the surgery the Arg level was significantly higher in young rats (C-2: 102.1±35.7 µmol/l; IR-2: 114.63±28.9 µmol/l) than in older ones (C-12: 41.88±44.7 µmol/l; IR-12: 28.64±30.6 µmol/l). In the C-2 group the Arg level (77.41±37.5 µmol/l) and Arg/ADMA (A/A) ratio (138.03±62.8 µmol/l) were significantly higher compared to the ischemic groups at 15 min and to all the other groups at 120 (Arg: 47.17±31.7 µmol/l; A/A: 88.28±66.2 µmol/l) and 240 min (Arg: 43.87±21.9 µmol/l; A/A: 118.02±106.3 µmol/l). In the IR-2 group Arg level (11.4±12.0 µmol/l) and A/A ratio (16.11±16.2 µmol/l) decreased significantly at 15 min and during the next phase of reperfusion the levels of those parameters were low, comparably to those in IR-12. As a result of IR, a decrease in DDAH activity and an increase in iNOS protein concentration were observed only in the young rats. CONCLUSIONS: We found that in the non-ischemic groups the Arg level may be affected by the aging process. Under IR conditions, important changes in DDAH-ADMA-NO pathway were observed only in young livers.

Influence of ezetimibe on ADMA-DDAH-NO pathway in rat liver subjected to partial ischemia followed by global reperfusion.

BACKGROUND: We evaluated effect of ezetimibe on selected parameters determining NO level in rat liver subjected to ischemia reperfusion (IR). METHODS: Rats received ezetimibe (5 mg/kg) (groups E0 and EIR) or saline solution (groups C0 and CIR) intragastrically for 21 days. Then, the livers of CIR and EIR underwent ischemia (60 min) and reperfusion (4 h). Blood samples were obtained before surgery to estimate activities of aminotransferases, and just before ischemia and during reperfusion to estimate asymmetric and symmetric dimethylarginine (ADMA, SDMA) and arginine (Arg) levels. After IR, dimethylarginine dimethylaminohydrolase (DDAH) activity and endothelial nitric oxide synthase (eNOS) protein concentration were measured in liver homogenates. DDAH and protein arginine methyltransferase (PRMT) mRNA were quantified by real-time PCR in liver tissue samples. RESULTS: In CIR, the ADMA level was significantly higher compared to all other groups in 30 min and to E0 group in 120 min of reperfusion. In EIR, ADMA was low, compared to non-ischemic groups. At 30 and 120 min of reperfusion, in non-ischemic groups the level of Arg and Arg/ADMA ratio were significantly higher than in ischemic groups and E0 was the group with the highest levels of those parameters of all. In CIR, eNOS protein concentration was significantly lower than in ezetimibe-treated groups. Activity of DDAH was significantly higher in E0 than in non-treated groups. In ischemic groups, DDAH mRNA expression was significantly higher than in non-ischemic ones and PRMT mRNA expression was significantly higher in C0 than in all other groups. CONCLUSIONS: Influence of ezetimibe on ADMA/DDAH/NO pathway demonstrated in this work may suggest protective properties of this drug on rat livers injured by IR and, to a lower extent, on livers non-subjected to IR.

Influence of water-soluble flavonoids, quercetin-5'-sulfonic acid sodium salt and morin-5'-sulfonic acid sodium salt, on antioxidant parameters in the subacute cadmium intoxication mouse model.

Water-soluble quercetin-5'-sulfonic acid sodium salt (NaQSA) and morin-5'-sulfonic acid sodium salt (NaMSA) could exert an antagonistic effect on cadmium intoxication. The aim of the study was to examine the influence of these substances on superoxide dismutase (SOD) and glutathione (GSH) levels in the mouse liver in the subacute cadmium intoxication model. NaQSA and NaMSA significantly counteracted cadmium-induced decreases in SOD and GSH levels. No significant differences in SOD and GSH levels between groups exposed to cadmium receiving NaQSA or/and NaMSA were observed.