Sevtap Aydın

Protective effects of curcumin against oxidative stress parameters and DNA damage in the livers and kidneys of rats with biliary obstruction

Curcumin, a most active antioxidant compound, has been suggested to have potential beneficial effects against most metabolic and psychological disorders, including cholestasis. In the present study, the effects of curcumin against oxidative stress and DNA damage induced by bile duct ligation (BDL) in Wistar albino rats for 14 days were investigated. The rats were divided into three following groups: Sham group, the BDL group and the BDL+curcumin group. A daily dose of 50mg/kg curcumin was given to the BDL+curcumin group intragastrically for 14 days. The biomarkers of hepatocellular damage were decreased in the BDL+curcumin group compared to the BDL group, indicating that curcumin recovered the liver functions. DNA damage as assessed by the alkaline comet assay was also found to be low in the BDL+curcumin group. Curcumin significantly reduced malondialdehyde and nitric oxide levels, and enchanced reduced glutathione levels and catalase, superoxide dismutase, and glutathione S-transferase enzymes activities in the livers and kidneys of BDL group. Curcumin treatment in BDL group was found to decrease tumor necrosis factor-alpha levels in the livers of rats. These results suggest that curcumin might have protective effects on the cholestasis-induced injuries in the liver and kidney tissues of rats.

Determination of seasonal variations in serum ochratoxin A levels in healthy population living in some regions of Turkey by enzyme-linked immunosorbent assay.

This study has been undertaken to investigate the regional and seasonal variability in ochratoxin A (OTA) exposure of healthy population living in Black Sea and Mediterranean regions of Turkey by measuring serum OTA concentrations. The mean serum concentrations of OTA were determined to be 0.137 ng/mL (0.0306-0.887 ng/mL) and 0.312 ng/mL (0.028-1.496 ng/mL) in all samples for winter and summer, respectively by enzyme-linked immunosorbent assay (ELISA). The differences between mean values of OTA in all serum samples collected in summer and winter were statistically significant. The highest OTA concentration was determined in the children living in Black Sea Region in summer. The mean daily intake levels of OTA in all samples were estimated as 0.182 ng/kg b.w./day and 0.408 ng/kg b.w./day in winter and summer, respectively. The results showed that the mean serum concentrations of OTA in healthy population in both regions were found not to be exceeded 1 ng/mL in agreement with the distribution reported in most European countries and that the daily intake levels of OTA were calculated below the tolerable daily intake levels given by regulatory authorities. However, overall results suggest that Turkish population living in these regions is continuously exposed to OTA and that the exposure levels are also elevated in summer period compared to winter.

Antioxidant and antigenotoxic effects of lycopene in obstructive jaundice.

BACKGROUND Obstructive jaundice, a frequently observed condition caused by obstruction of the common bile duct or its flow and seen in many clinical situations, may end up with serious complications like sepsis, immune depression, coagulopathy, wound breakdown, gastrointestinal hemorrhage, and hepatic and renal failures. Intrahepatic accumulation of reactive oxygen species is thought to be an important cause for the possible mechanisms of the pathogenesis of cholestatic tissue injury from jaundice. Carotenoids have been well described that are able to scavenge reactive oxygen species. Lycopene, a carotenoid present in tomatoes, tomato products, and several fruits and vegetables, have been suggested to have antioxidant activity, so may play a role in certain diseases related to the oxidative stress. The aim of the present study was to determine the effects of lycopene on oxidative stress and DNA damage induced by experimental biliary obstruction in Wistar albino rats. MATERIALS AND METHODS Daily doses of 100 mg/kg lycopene were given to the bile duct-ligation (BDL) rats orally for 14 days. DNA damage was evaluated by an alkaline comet assay. The levels of aspartate transferase, amino alanine transferase, gamma glutamyl transferase, alkaline phosphatase, and direct bilirubin were analyzed in plasma for the determination of liver functions. The levels of malondialdehyde, reduced glutathione, nitric oxide, catalase, superoxide dismutase, and glutathione S transferase were determined in the liver and kidney tissues. Pro-inflammatory cytokine tumor necrosis factor-alpha level was determined in the liver tissues. Histologic examinations of the liver and kidney tissues were also performed. RESULTS According to this study, lycopene significantly recovered the parameters of liver functions in plasma, reduced malondialdehyde and nitric oxide levels, enhanced reduced glutathione levels, as well as enhancing all antioxidant enzyme activity in all tissues obtained from the BDL group. Moreover, the parameters of DNA damage in the liver and kidney tissue cells, whole blood cells, and lymphocytes were significantly lower in the lycopene-treated BDL group, compared with the BDL group. CONCLUSIONS Lycopene significantly reduced the DNA damage, and markedly recovered the liver and kidney tissue injuries seen in rats with obstructive jaundice.

Assessment of DNA integrity (COMET assay) in sperm cells of boron-exposed workers

An extension of a male reproductive study conducted in a boric acid/borate production zone at Bandırma, Turkey, is presented. The relation between DNA-strand breaks (COMET assay, neutral and alkaline version) in sperm cells and previously described sperm quality parameters was investigated in boron-exposed males. A correlation between blood boron levels and mean DNA-strand breaks in sperm was weak, and DNA-strand breaks in sperm were statistically not different between control and exposed groups. Therefore, increasing boron exposures had no additional contribution in addition to already pre-existing DNA-strand breaks in the sperm cells. Weak but statistically significant correlations between DNA-strand breaks and motility/morphology parameters of sperm samples were observed in the neutral version of the COMET assay, while correlations between the same variables were statistically not significant in the alkaline version. A likely reason for these negative results, even in highly exposed humans, is that experimental exposures that had led to reproductive toxicity in animals were significantly higher than any boron exposures, which may be reached under realistic human conditions.

Modulating Effects of Pycnogenol® on Oxidative Stress and DNA Damage Induced by Sepsis in Rats

The aim of this study was to evaluate the protective effects of Pycnogenol® (Pyc), a complex plant extract from the bark of French maritime pine, on oxidative stress parameters (superoxide dismutase (SOD), and glutathione peroxidase (GPx) activities and total glutathione (GSH) and malondialdehyde (MDA) levels), an inflammatory cytokine (tumor necrosis factor alpha (TNF‐α) level) and also DNA damage in Wistar albino rats. Rats were treated with 100 mg/kg intraperitonally Pyc following the induction of sepsis by cecal ligation and puncture. The decreases in MDA levels and increases in GSH levels, and SOD and GPx activities were observed in the livers and kidneys of Pyc‐treated septic rats. Plasma TNF‐α level was found to be decreased in the Pyc‐treated septic rats. In the lymphocytes, kidney, and liver tissue cells of the sepsis‐induced rats, Pyc treatment significantly decreased the DNA damage and oxidative base damage using standard alkaline assay and formamidopyrimidine DNA glycosylase‐modified comet assay, respectively. In conclusion, Pyc treatment might have a role in the prevention of sepsis‐induced oxidative damage not only by decreasing DNA damage but also increasing the antioxidant status and DNA repair capacity in rats. Copyright

The protective role of ferulic acid on sepsis-induced oxidative damage in Wistar albino rats

Oxidative stress has an important role in the development of sepsis-induced multiorgan failure. Ferulic acid (FA), a well-established natural antioxidant, has several pharmacological activities including anti-inflammatory, anticancer and hepatoprotective. This study aimed to investigate the effects of FA on sepsis-induced oxidative damage in Wistar albino rats. Sepsis-induced DNA damage in the lymphocytes, liver and kidney cells of rats were evaluated by comet assay with and without formamidopyrimidine DNA glycosylase (Fpg). The oxidative stress parameters such as superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities and total glutathione (GSH) and malondialdehyde (MDA) levels were also measured. It is found that DNA damage in sepsis+FA-treated group was significantly lower than the sepsis group. FA treatment also decreased the MDA levels and increased the GSH levels and SOD and GSH-Px activities in the sepsis-induced rats. It seems that FA might have ameliorative effects against sepsis-induced oxidative damage.

Effects of Low-Dose Doxycycline and Bisphosphonate Clodronate on Alveolar Bone Loss and Gingival Levels of Matrix Metalloproteinase-9 and Interleukin-1β in Rats With Diabetes: A Histomorphometric and Immunohistochemical Study

BACKGROUND Bisphosphonates (BPs) and low-dose doxycycline (LDD) have been shown to inhibit bone resorption and to improve the levels of proinflammatory mediators and destructive enzymes in gingival tissues, respectively. The purpose of this study is to evaluate the effect of mono and combined BP clodronate and LDD therapies in reducing gingival levels of matrix metalloproteinase-9 (MMP-9), interleukin-1β (IL-1β), and alveolar bone loss in rats with diabetes. METHODS Fifty adult Wistar rats were divided into five study groups as follows: 1) group 1 = diabetes control; 2) group 2 = diabetes + periodontitis; 3) group 3 = diabetes + periodontitis + LDD; 4) group 4 = diabetes + periodontitis + clodronate; and 5) group 5 = diabetes + periodontitis + LDD + clodronate. LDD and clodronate were given as a single agent or as combination therapy during the 7 days of the post-experimental periodontitis period. On day 7, the rats were sacrificed, the mobility of the tooth was recorded, and block biopsies were removed. The gingival tissues were analyzed histologically and immunohistochemically for expression of MMP-9 and IL-1β. Alveolar bone loss was evaluated morphometrically under a light microscope. Data analysis was performed statistically by Kruskal-Wallis and post hoc Tukey and Spearman correlation tests. RESULTS Alveolar bone loss was significantly greater in groups 2 through 5 than group 1 (P <0.05) but was not significantly different among groups 2 through 5 (P >0.05). Animals with periodontitis (group 2) expressed significantly higher levels of MMP-9 and IL-1β compared with those without periodontitis (group 1) (P <0.05). MMP-9 expression was significantly lower in group 3 than groups 1, 2, and 5 (P <0.05). IL-1β expression was significantly lower in the groups 1, 3, 4, and 5 than 2 (P <0.01) but was not significantly different among groups 1, 3, 4, and 5. Positive correlations were found between alveolar bone loss and density of inflammation (ρ = 0.319, P = 0.021) and between MMP-9 and IL-1β (ρ = 0.418, P = 0.002), respectively. CONCLUSION Our findings suggest that ligature-induced periodontitis in animals with diabetes results in significantly higher levels of MMP-9 and IL-1β expression in gingiva. The use of mono and combined clodronate and LDD administrations may significantly reduce levels of MMP-9 and IL-1β expression. However, drug administration did not affect alveolar bone levels during the study period.

Effects of the probiotic agent Saccharomyces Boulardii on the DNA damage in acute necrotizing pancreatitis induced rats

Pancreatitis is a mild and self-limiting disease. Although severe forms such as acute necrotizing pancreatitis (ANP) are rare it is associated with significant mortality rate reported to be 30—70%. Probiotics are viable microbial dietary supplements when introduced in sufficient quantities can have beneficial effects. The physiological effects of probiotics include suppression of bacterial infections, production of some digestive enzymes and vitamins and reconstruction of normal intestinal microflora. In the present study, the aim was to investigate the role of probiotics on the DNA damage in the peripheral lymphocytes, in the exfoliated epithelial cells and lymphocytes of the peritoneal fluids and in the pancreatic acinar cells of ANP induced rats. DNA damage was determined by COMET assay. ANP was induced by intravenous infusion of cerulein and superimposed infusion glycodeoxycholic acid into biliopancreatic duct. Saccharomyces Boulardii was used as the probiotic agent. DNA damage in pancreatic acinar cells and exfoliated epithelial cells and the lymphocytes of the peritoneal fluids; was significantly higher in pancreatitis group compared to the controls and probiotic treated groups (P <0.001). No significant difference was observed in the DNA damage between the groups in the peripheral lymphocytes. In conclusion; our results support that probiotic agent Saccharomyces Boulardii can diminish bacterial infections and offer health benefits in the therapy of pancreatitis. Human & Experimental Technololgy (2007) 26, 653—661

Use of in vitro assays to assess the potential cytotoxic, genotoxic and antigenotoxic effects of vanillic and cinnamic acid

Abstract Vanillic acid (VA) found in vanilla and cinnamic acid (CA) the precursor of flavonoids and found in cinnamon oil, are natural plant phenolic acids which are secondary aromatic plant products suggested to possess many physiological and pharmacological functions. In vitro and in vivo experiments have shown that phenolic acids exhibit powerful effects on biological responses by scavenging free radicals and eliciting antioxidant capacity. In the present study, we investigated the antioxidant capacity of VA and CA by the trolox equivalent antioxidant capacity (TEAC) assay, cytotoxicity by neutral red uptake (NRU) assay in Chinese Hamster Ovary (CHO) cells and also the genotoxic and antigenotoxic effects of these phenolic acids using the cytokinesis-blocked micronucleus (CBMN) and the alkaline comet assays in human peripheral blood lymphocytes. At all tested concentrations, VA (0.17–67.2 μg/ml) showed antioxidant activity but CA (0.15–59.2 μg/ml) did not show antioxidant activity against 2,2-azino-bis (3-ethylbenz-thiazoline-6-sulphonic acid) (ABTS). VA (0.84, 4.2, 8.4, 16.8, 84 and 168 μg/ml) and CA (0.74, 3.7, 7.4, 14.8, 74, 148 μg/ml) did not have cytotoxic and genotoxic effects alone at the studied concentrations as compared with the controls. Both VA and CA seem to decrease DNA damage induced by H2O2 in human lymphocytes.

Assessment of the cytotoxic, genotoxic, and antigenotoxic potential of Pycnogenol® in in vitro mammalian cells

Pycnogenol® (PYC), a standardized plant extract obtained from the bark of the French maritime pine Pinus pinaster, has been suggested to exert strong antioxidant activity and used as a phytochemical remedy for various diseases. In this study, we investigated the antioxidant capacity of PYC by the trolox equivalent antioxidant capacity (TEAC) assay and the cytotoxicity by neutral red uptake (NRU) test in Chinese Hamster Ovary (CHO) cells. The genotoxic and antigenotoxic effects of PYC were evaluated by the cytokinesis-blocked micronucleus (CBMN) and alkaline comet assays in human peripheral blood lymphocytes. At the concentrations of 2-200 μg/ml, PYC was found to have antioxidant activity. The viability of CHO cells during 24h exposure were not affected at the concentrations of 5-150 μg/ml of PYC. IC50 value of PYC was found to be 285 μg/ml. At the concentrations above 100 μg/ml, PYC alone induced DNA damage and increased MN frequency, although PYC at all concentrations in a dose dependent manner revealed a reduction in the frequency of MN and the extent of DNA damage induced by H2O2. These results suggest PYC might reduce H2O2 induced chromosome breakage and loss and DNA damage in cultured human lymphocytes.