Variations in erythrocyte antioxidant levels and lipid peroxidation status and in serum lipid profile parameters in relation to blood haemoglobin A1c values in individuals with type 2 diabetes mellitus.

AIMS: The present study aimed to evaluate the antioxidant and lipid peroxidation status in erythrocytes and serum lipid profile parameters, in relation to haemoglobin A1c (HbA1c) concentrations, in patients with type 2 diabetes mellitus and in normal healthy individuals. METHODS: Sixty test individuals with diabetes and 15 control individuals were categorized as: Group I, control (non-diabetes); Group II, individuals with diabetes with HbA1c levels ≤7.0% (53 mmol/mol); Group III, individuals with diabetes with HbA1c levels between 7.1 and 8.0% (54 and 64 mmol/mol); Group IV, individuals with diabetes with HbA1c levels between 8.1 and 9.0% (65 and 75 mmol/mol); Group V, individuals with diabetes with HbA1c levels >9.0% (75 mmol/mol). Blood samples were collected to measure: blood glucose and HbA1c levels; haemolysate levels of enzymatic antioxidants and non-enzymatic antioxidants and malondialdehyde (MDA); and serum total cholesterol, triglyceride and high-density lipoprotein (HDL)-cholesterol levels. Correlations between blood HbA1c values and all parameters were sought. RESULTS: Significantly lower mean activities/levels of antioxidant parameters and significantly higher mean levels of MDA were noted in haemolysate samples from patients with diabetes than in those from control individuals. Significantly higher mean serum concentrations of total cholesterol and triglycerides and significantly lower mean concentrations of HDL-cholesterol were noted in patients with diabetes than in control individuals. Further, moderate to strong correlations were observed between values of antioxidants, MDA and lipid profile parameters and blood concentrations of HbA1c. CONCLUSION: These results suggest that HbA1c values may be potentially useful not only to indicate long-term glycemic control to indicate onset of complications at a clinically detectable level and molecular level.

Antihypercholesterolemic and Antioxidative Potential of an Extract of the Plant, Piper betle, and Its Active Constituent, Eugenol, in Triton WR-1339-Induced Hypercholesterolemia in Experimental Rats.

Hypercholesterolemia is a dominant risk factor for atherosclerosis and cardiovascular diseases. In the present study, the putative antihypercholesterolemic and antioxidative properties of an ethanolic extract of Piper betle and of its active constituent, eugenol, were evaluated in experimental hypercholesterolemia induced by a single intraperitoneal injection of Triton WR-1339 (300 mg/kg b.wt) in Wistar rats. Saline-treated hypercholesterolemic rats revealed significantly higher mean blood/serum levels of glucose, total cholesterol, triglycerides, low density and very low density lipoprotein cholesterol, and of serum hepatic marker enzymes; in addition, significantly lower mean serum levels of high density lipoprotein cholesterol and significantly lower mean activities of enzymatic antioxidants and nonenzymatic antioxidants were noted in hepatic tissue samples from saline-treated hypercholesterolemic rats, compared to controls. However, in hypercholesterolemic rats receiving the Piper betle extract (500 mg/kg b.wt) or eugenol (5 mg/kg b.wt) for seven days orally, all these parameters were significantly better than those in saline-treated hypercholesterolemic rats. The hypercholesterolemia-ameliorating effect was better defined in eugenol-treated than in Piper betle extract-treated rats, being as effective as that of the standard lipid-lowering drug, lovastatin (10 mg/kg b.wt). These results suggest that eugenol, an active constituent of the Piper betle extract, possesses antihypercholesterolemic and other activities in experimental hypercholesterolemic Wistar rats.

Putative free radical-scavenging activity of an extract of Cineraria maritima in preventing selenite-induced cataractogenesis in Wistar rat pups.

PURPOSE: To investigate the possible free radical-scavenging activity of an extract of Cineraria maritima on selenite-induced cataractous lenses in Wistar rat pups. METHODS: In the present study, Wistar rat pups were divided into three experimental groups. On P10, Group I (control) rat pups received an intraperitoneal injection of 0.89% saline. Rats in groups II (selenite-challenged, untreated) and III (selenite-challenged, C. maritima treated) received a subcutaneous injection of sodium selenite (19 µmol/kg bodyweight); Group III rat pups also received an intraperitoneal injection of the extract of C. maritima (350 mg/kg bodyweight) once daily P9-14. Both eyes of each pup were examined from P16 until P30. Cytochemical localization of nitroblue tetrazolium salts and generation of superoxide, hydroxyl, and nitric oxide levels were measured. The expression of the inducible nitric oxide synthase gene was evaluated with reverse transcription-PCR. Immunoblot analysis was also performed to confirm the differential expression of the inducible nitric oxide synthase protein. RESULTS: Subcutaneous injection of sodium selenite led to severe oxidative damage in the lenticular tissues, shown by increased formation of formazan crystals, elevated generation of superoxide, hydroxyl, and nitric oxide radicals, and elevated inducible nitric oxide synthase gene and protein expression that possibly contributed to the opacification of the lens and thus cataract formation. When rat pups were treated with intraperitoneal administration of the extract of C. maritima, the generation of free radicals as well as the messenger ribonucleic acid and protein expression of inducible nitric oxide synthase were maintained at near normal levels. CONCLUSIONS: The data generated by this study suggest that an ethanolic extract of C. maritima possibly prevents cataractogenesis in a rat model by minimizing free radical generation.

Oxidative stress in experimental rodent corneas infected with aflatoxigenic and nonaflatoxigenic Aspergillus flavus.

PURPOSE: To seek a possible association between aflatoxigenicity and oxidative stress in keratitis caused by Aspergillus flavus in an experimental rodent model. METHODS: Wistar rats were divided into 3 groups of 6 each. Group 1 served as mock-inoculated controls. Experimental fungal keratitis was induced in group 2 and group 3 rats using aflatoxigenic and nonaflatoxigenic A. flavus conidial suspensions, respectively, and clinical features were scored for 5 days after inoculation. At this time, animals were killed, and test corneas were excised and examined histologically. Expression of IL-1ß and TNF-α genes was sought in excised corneas. Levels of malondialdehyde (MDA) and reduced glutathione (GSH) and activities of key antioxidant enzymes were measured in excised corneas and fungal mycelial homogenates. Antioxidant enzyme isoforms were sought in mycelial homogenates by native polyacrylamide gel electrophoresis. RESULTS: Mean levels of MDA and GSH and mean activities of catalase, superoxide dismutase, and glutathione peroxidase were significantly (P < 0.05) higher in a mycelial homogenate of aflatoxigenic A. flavus than in the nonaflatoxigenic mycelial homogenate. Increased numbers of well-stained isoforms were detected in aflatoxigenic mycelial homogenates. Significantly (P < 0.05) higher expression profiles of IL-1ß and TNF-α genes, MDA and GSH levels, and antioxidant enzyme activities were noted in group 2 rat corneas than in group 3 rat corneas. Clinical and histological scores suggested a more severe keratitis in group 2 rat corneas than in group 1 and group 3 rat corneas. CONCLUSIONS: Aflatoxigenicity is associated with more intense oxidative stress in experimental A. flavus keratitis.

Antihypercholesterolemic and antioxidative effects of an extract of the oyster mushroom, Pleurotus ostreatus, and its major constituent, chrysin, in Triton WR-1339-induced hypercholesterolemic rats.

Hypercholesterolemia and oxidative stress are known to accelerate coronary artery disease and progression of atherosclerotic lesions. In the present study, an attempt was made to evaluate the putative antihypercholesterolemic and antioxidative effects of an ethanolic extract of the oyster mushroom (Pleurotus ostreatus) and chrysin, one of its major components, in hypercholesterolemic rats. Hypercholesterolemia was induced in rats by a single intraperitoneal injection of Triton WR-1339 (300 mg/kg body weight (b.wt.)), which resulted in persistently elevated blood/serum levels of glucose, lipid profile parameters (total cholesterol, triglycerides, low-density lipoprotein-, and very low-density lipoprotein-cholesterol), and of hepatic marker enzymes (alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, and lactate dehydrogenase). In addition, lowered mean activities of hepatic antioxidant enzymes (catalase, superoxide dismutase, and glutathione peroxidase) and lowered mean levels of nonenzymatic antioxidants (reduced glutathione, vitamin C, and vitamin E) were observed. Oral administration of the mushroom extract (500 mg/kg b.wt.) and chrysin (200 mg/kg b.wt.) to hypercholesterolemic rats for 7 days resulted in a significant decrease in mean blood/serum levels of glucose, lipid profile parameters, and hepatic marker enzymes and a concomitant increase in enzymatic and nonenzymatic antioxidant parameters. The hypercholesterolemia-ameliorating effect was more pronounced in chrysin-treated rats than in extract-treated rats, being almost as effective as that of the standard lipid-lowering drug, lovastatin (10 mg/kg b.wt.). These results suggest that chrysin, a major component of the oyster mushroom extract, may protect against the hypercholesterolemia and elevated serum hepatic marker enzyme levels induced in rats injected with Triton WR-1339.

Deciphering the potential efficacy of acetyl-L-carnitine (ALCAR) in maintaining connexin-mediated lenticular homeostasis.

PURPOSE: To determine the putative role of acetyl-L-carnitine (ALCAR) in maintaining normal intercellular communication in the lens through connexin. METHODS: In the present study, Wistar rat pups were divided into 3 groups of eight each. On postpartum day ten, Group I rat pups received an intraperitoneal injection (50 µl) of 0.89% saline. Rats in Groups II and III received a subcutaneous injection (50 µl) of sodium selenite (19 µmol/kg bodyweight); Group III rat pups also received an intraperitoneal injection of ALCAR (200 mg/kg bodyweight) once daily on postpartum days 9-14. Both eyes of each pup were examined from day 16 up to postpartum day 30. Alterations in the mean activity of the channel pumps, calcium-ATPase and sodium/potassium-ATPase, were determined. The expression of genes encoding key lenticular gap junctions (connexin 46 and connexin 50) and a channel pump (plasma membrane Ca(2+)-ATPase [PMCA1]) was evaluated by reverse transcription-PCR. Immunoblot analysis was also performed to confirm the differential expression of key lenticular connexin proteins. In addition, bioinformatics analysis was performed to determine the interacting residues of the connexin proteins with ALCAR. RESULTS: Significantly lower mean activities of Ca(2+)-ATPase and Na(+)/K(+) -ATPase were observed in the lenses of Group II rats than those in Group I rat lenses. However, the observed mean activities of Ca(2+)-ATPase and Na(+)/K(+)-ATPase in Group III rat lenses were significantly higher than those in Group II rat lenses. The mean mRNA transcript levels of the connexin 46 and connexin 50 genes were significantly lower, while the mean levels of PMCA1 gene transcripts were significantly higher, in Group II rat lenses than in Group I rat lenses. Immunoblot analysis also confirmed the altered expression of connexin proteins in lysates of whole lenses of Group II rats. However, the expression of connexin 46 and connexin 50 proteins in lenses from group III rats was essentially similar to that noted in lenses from normal (Group I) rats. Hydrogen bond-interaction between ALCAR and amino acid residues at the functional domain regions of connexin 46 and connexin 50 proteins was also demonstrated through bioinformatics tools. CONCLUSIONS: The results suggest that ALCAR plays a key role in maintaining lenticular homeostasis by promoting gap junctional intercellular communication.

Acetyl-L-carnitine prevents carbon tetrachloride-induced oxidative stress in various tissues of Wistar rats.

Acetyl-L-carnitine (ALCAR) has been shown to prevent experimental selenite cataractogenesis, a manifestation of oxidative stress, but little is known about its potential in other settings of oxidative stress. The present study was based on the hypothesis that ALCAR prevents carbon tetrachloride (CCl(4))-induced oxidative stress in vital tissues. Male albino Wistar rats were divided into three groups, each of six rats. Group I (control) rats received only vehicle (1 ml/kg b.w.) for 4 days; Group II (CCl(4)-exposed, untreated) rats received CCl(4) (2 ml/kg b.w.) on the second and third days and vehicle on the first and fourth days; Group III (CCl(4)-exposed, ALCAR-treated) rats received ALCAR (200 mg/kg b.w.) for 4 days and CCl(4) on the second and third days. All administrations were made intraperitoneally. After the experimental period, significantly (P < 0.05) elevated mean serum levels of aspartate transaminase, alanine transaminase, alkaline phosphatase, and lactate dehydrogenase were observed in Group II rats when compared to Group I and Group III rats. The mean levels of vitamin C, vitamin E, and reduced glutathione and the mean activities of superoxide dismutase, catalase, and glutathione peroxidase were significantly (P < 0.05) lower in samples of hemolysate and of liver, kidney, and brain tissues of Group II rats than those in Group I and Group III rats. The mean level of lipid peroxidation was significantly (P < 0.05) higher in Group II rats than that in Group I and Group III rats. Moreover, the CCl(4)-induced upregulation of inducible nitric oxide synthase expression was prevented by ALCAR in the liver and brain tissues. These results suggest that ALCAR is able to prevent the CCl(4)-induced oxidative stress.

Prevention of selenite-induced cataractogenesis by an ethanolic extract of Cineraria maritima: an experimental evaluation of the traditional eye medication.

In the present study, the antioxidant potential of an ethanolic extract of Cineraria maritima and its efficacy in preventing selenite-induced cataractogenesis were assessed in vitro and in vivo. In the in vitro phase of the study, lenses dissected out from the eyes of Wistar rats were incubated for 24 h at 37 °C in Dulbecco's modified Eagle medium (DMEM) alone (group I), in DMEM containing 100 µM of selenite only (group II), or in DMEM containing 100 µM of selenite and 300 µg/ml C. maritima extract added at the same time (group III). Gross morphological examination of the lenses revealed dense opacification in group II, minimal opacification in group III, and no opacification in group I lenses. The mean activities of the antioxidant enzymes catalase, glutathione peroxidase, and superoxide dismutase were significantly lower in group II than in group I or group III lenses, while malondialdehyde concentration was significantly higher in group II lenses than in group I and group III lenses. In the in vivo phase of the study, dense opacification of lenses was noted in all rat pups (100%) that had received a single subcutaneous injection of sodium selenite alone (19 µM/kg body weight) on postpartum day 10, whereas cataract formation occurred in only 33.3% of rat pups that had received selenite as well as an intraperitoneal injection of the extract of C. maritima (350 mg/kg body weight) for five consecutive days. These observations suggest that the ethanolic extract of C. maritima may prevent experimental selenite-induced cataractogenesis.