Effect of crocin on antioxidant gene expression, fibrinolytic parameters, redox status and blood biochemistry in nicotinamide-streptozotocin-induced diabetic rats

Background

Diabetes is regarded as an epidemiological threat for the twenty-first century. Phytochemicals with known pharmaceutical properties have gained interest in the field of alleviating secondary complications of diseases. Such a substance is crocin, a basic constituent of saffron (Crocus sativus). The present study aimed at examining the beneficial effects of per os crocin administration on the antioxidant status, blood biochemical profile, hepatic gene expression and plasminogen activator inhibitor-1 activity (PAI-1) in the liver, kidney and plasma (an important marker of pre-diabetic status and major factor of thrombosis in diabetes) of healthy rats, as well as of rats with nicotinamide-streptozotocin-induced diabetes.

Results

Diabetes disrupted the oxidation-antioxidation balance, while crocin improved the antioxidant state in the liver by significantly affecting SOD1 gene expression and/or by restoring SOD and total antioxidant capacity (TAC) levels. In the kidney, crocin improved hydrogen peroxide decomposing activity and TAC. In blood, hepatic transaminases ALT and AST decreased significantly, while there was a trend of decrease regarding blood urea nitrogen (BUN) levels. The expression of PAI-1 gene was affected in the liver by the dose of 50 mg kg⁻¹.

Conclusions

Crocin treatment contributed in restoring some parameters after diabetes induction, primarily by affecting significantly hepatic transaminases ALT and AST, SOD1 and PAI-1 gene expression and nephric H₂O₂ decomposing activity. In conclusion, crocin did contribute to the alleviation of some complications of diabetes.

The effects of a water polo game on the blood redox status of male water polo players

AIM

The purpose of this study was to examine the effects of a real water polo game on the oxidative stress and antioxidants markers of male water polo players. The importance of this study is that it is the first to examine the oxidative stress and antioxidants markers after a water polo game, considering the specific and high demands of the latter.

METHODS

Twelve players (25.8±3.7 years) were assessed from two teams. The oxidative stress and antioxidants markers which were measured were TBARS, Protein Carbonyls, GSH and GSSG, Total Antioxidant Capacity (TAC) and Catalase.

RESULTS

An increase was found after the game for TBARS, for catalase, for GSH, and GSSG. Protein Carbonyls, TAC and the GSH/GSSG ratio did not change significantly.

CONCLUSION

The water polo game was found to be a strong stimulus for oxidative stress, while alterations seem to appear for the antioxidant capability, as indicated by increase of catalase and GSH. The increase of the latter is controversial to the usual effect post exercise. A possible explanation for this effect could be the activation of GSH synthesis in order to meet the increased needs for antioxidant protection. Also, it should be considered that blood samples were taken 10-20 min. after the game, so it is possible that in well-trained subjects, this time period is enough for the conversion of GSSG back to GSH. Yet, it can be stated that, despite the enhanced antioxidant defense of the players, oxidative stress could not be prevented.

Effect of a special carbohydrate-protein cake on oxidative stress markers after exhaustive cycling in humans

Exercise has been associated with oxidative stress that is correlated with muscle fatigue and reduced exercise performance. The aim of this study was to examine the effects of a special cake (consisting of carbohydrate to whey protein 3.5:1) vs an isocaloric carbohydrate cake on biomarkers of oxidative stress in 9 males after exhaustive cycling. A randomized single-blind cross-over study was completed. They performed one trial involving a 2-h exercise on a cycle ergometer at 60-65% VO(2)max followed by a 4-h recovery and then a second trial involved an 1-h exercise at 60-65% VO(2)max which was increased at 95% VO(2)max (time trial). The subjects received 4 experimental or placebo cakes after the first trial (the first immediately after and then one every hour). Blood samples were collected at eight time intervals: pre-exercise, 30 min, 1.5 h and 4 h post-exercise, post time Trial, 1 h, 24 h and 48 h post time Trial. Thiobarbituric Acid Reactive Substances (TBARS), protein carbonyls, total antioxidant capacity (TAC), catalase and glutathione (GSH) were determined spectrophotometrically. The mean time to exhaustion did not differ upon cake consumption. Consumption of the special cake reduced TBARS significantly, but had no effect on other oxidative stress markers.