Effects of photoperiod variations and alpha-lipoic acid treatment on melatonin,cortisol, and oxidative stress levels in the blood of rats

Abstract

This study aimed to investigate the effects of frequently changing photoperiods and alpha-lipoic acid treatment on melatonin, cortisol, oxidative markers, and some blood parameters. Eighty-four rats were randomly and equally divided into 7 groups: a control group, 3 prolonged light groups, and 3 prolonged dark groups. The study was completed in 2 stages, with 1-and 4-week periods, respectively. Blood samples were obtained at the end of the first and fourth weeks, and at the end of the dark period for the first and second stages. Serum aspartate aminotransferase and creatinine levels were significantly elevated in the prolonged dark olive oil group in the second stage. These values were similar to those of the control group in the prolonged dark water and alpha-lipoic acid groups. There was no statistically significant difference in total oxidant status between the prolonged dark olive oil group and the control group; however, the numerical total oxidant status value was increased. Higher urea and blood urea nitrogen levels were noted in the prolonged dark groups as compared with those in the prolonged light groups in the second stage. Melatonin and cortisol levels did not significantly change. The applied photoperiod changes in this study did not constitute a direct metabolic stressor for rats.

Oxidative Stress in Rats is Modulated by Seasonal Consumption of Sweet Cherries from Different Geographical Origins: Local vs. Non-Local

“…On the other hand, AST activity at the hepatic level was modulated by photoperiod exposure, reaching the lowest activity when rats were exposed to the long photoperiod (two-way ANOVA Figure 2b). This finding is in agreement with the data reported by Hardeland et al [30], who demonstrated that mouse liver AST activity is at its maximum during the dark photoperiod; our data also concur with the results reported by Çevik and Aslan [31], who observed that prolonged dark periods enhance the oxidation of nutritional fatty acids and that this oxidation triggers an increase in the AST levels. In contrast, the activity of ALT was not modulated by exposure to the photoperiods.…”

“…This finding agrees with the data obtained by Mariné-Casadó et al [4], who previously detected a lack of differences in the ALT values between rats exposed to three photoperiods; similar results confirmed that increasing light photoperiod had no significant effects [32]. It is important to define the status of these biomarkers because ALT and AST are intracellular enzymes released from damaged hepatocytes into the blood following hepatocellular injury [31].…”

Evaluation of effects of melatonin and caffeic acid phenethyl ester on acute potassium dichromate toxicity and genotoxicity in rats

“…Serum melatonin levels were measured with ELISA method[ 20 ] (Cusabio Biotech, Wuhen, China) according to the manufacturer's instructions.…”

Biochemistry and Antioxidant Effects of Melatonin

“…While melatonin shows a stimulating effect on the gonads in animals, such as sheep, goats, and deer, it shows suppressive properties in animals, such as horses, hamsters, and camels [13]. Melatonin acts as a timer by providing to follow-up the changes in the light/dark ratio of the animal seasonally [14].…”