The effect of pumpkin seeds hydroalcoholic extract and endurance training on mitochondrial biogenesis markers and DNA damage in Ovarian tissue in rats toxicated by hydrogen peroxide

Free radicals or reactive oxygen species (ROS) are highly active chemical compounds that can cause oxidative damage to tissues by attacking macromolecules such as lipids, carbohydrates and nucleic acids. There are several defense mechanisms in the body against free radicals. Under physiological conditions, there is a balance between the production of free radicals and antioxidant defense systems. Increasing the production of free radicals due to exposure to environmental oxidants and increasing their production in the body and reducing the antioxidant capacity causes oxidative stress. This imbalance in Pro-oxidants-antioxidant balance (PAB) causes damage to cell DNA and intracellular organs, especially mitochondria. Studies have shown the positive effects of regular exercise on improving the ratio of prooxidants to antioxidants and factors involved in mitochondrial biogenesis and DNA degradation. Some studies have suggested increasing the use of antioxidants or antioxidant supplements during or after exercise to reduce the peroxidation of lipids and proteins, thereby reducing the destructive effects of oxidative active species on cells and tissues. Pumpkin seeds are rich sources of proteins, phytosterols, polyunsaturated fatty acids including linoleic, linolenic, vitamins (A, B, E and folic acid) and antioxidants such as carotenoids, lutein, tocopherol. Are chlorophyll and elements such as zinc and selenium, which are necessary for the normal functioning of the reproductive organs. Due to the fact that pumpkin contains these compounds, it is likely to affect the function of the pituitary gland axis and the concentration of sex hormones. Phenolic compounds in pumpkin seed extract inhibit lipid peroxidation, these compounds also inhibit free radicals.The protective role of pumpkin seed extract on ovarian DNA damage parameters has not been elucidated yet. It is necessary to evaluate the ratio of prooxidants to antioxidants and the balance between them. Therefore, the present study aims to investigate the effect of pumpkin seeds hydroalcoholic extract and endurance training on mitochondrial biogenesis markers and DNA damage in the Ovarian tissue in rats toxicated by hydrogen peroxide.

In this semi-experimental study, 42 female Wistar rats randomly were divided into 7 groups. All groups received 100 mg/kg body weight of hydrogen peroxide (H2O2) for 14 days intraperitoneal. Rats in supplemented groups received hydrophilic the rats received supplemental hydroalcoholic extract of pumpkin seeds at doses of 1 and 2 mg/kg body weight per day by gavage method. Aerobic training was performed on a treadmill at a speed of 23 m/min, 30 min/day, 5 days/week for eight weeks. Twenty-four hours after the last training session, rat Ovarian tissue was collected. Data were analyzed using by two-way ANOVA and Bonferroni post hoc test at p<0.05.

The results showed that Aerobic training, pumpkin seed and combined intervention of pumpkin seeds with aerobic training resulted in a significant increase of methyl guanine levels and oxidant-prooxidant (PAB) equilibrium, as well as a significant decrease in adenosine triphosphate (ATP) and malondialdehyde (MDA) in the Ovarian tissue (p<0.05).

The results of the present study showed that aerobic training, pumpkin seeds and intervention of pumpkin seeds and aerobic training improves the levels of PAB, MDA, ATP and 6-methylguanine in the ovarian tissue of rats poisoned with hydrogen peroxide. The mechanism that reduces lipid peroxidation in the exercise group is glycemic control and reduction of fat profile parameters after exercise, which provides important effects on reducing oxidative stress parameters and provides more support for evidence of the possible protective effect of exercise against oxidative stress. the results of studies show the positive effects of exercise on oxidative stress, which can also be useful for reducing the concentration of lipid peroxidation in conditions of increased oxidative stress and imbalance between ROS production.Another important possible mechanism of exercise-induced cellular protection may be the ability to block the formation of free radicals. Oxygen-reactive species are produced in the mitochondrial electron transfer chain as a natural product, but can lead to cell death when their levels exceed cell antioxidant capacity. The first mechanism that affects the indicators of oxidative stress following exercise is exercise status (type, intensity and duration of exercise). Long-term exercise training counteracts this effect by increasing antioxidant enzymes and thus reducing the production of free radicals. Therefore, it seems that aerobic training in the present study can be a good solution to treat metabolic disorders and reduce DNA damage in ovarian tissue following hydrogen peroxide toxicity. The mechanism of the effect of pumpkin seed extract on the oxidative parameters of reproductive organs has not been precisely determined. Pumpkin seeds, if used as a medicinal and herbal supplement, are a good source of zinc and unsaturated fatty acids and phytosterols, which are effective in preventing chronic diseases of the reproductive organs, especially the ovaries. Pumpkin seeds contain phytoestrogens. One of the side properties of phytoestrogens is antioxidant activity. Therefore, in the present study, the phytoestrogens in pumpkin seed extract may have reduced lipid peroxidation and reduced DNA damage in ovarian tissue. In addition, pumpkin seeds contain amounts of the element zinc. The zinc in pumpkin seeds acts as an antioxidant against free radical attack and prevents oxidation and free radical formation. In the present study, 1 g and 2 g of pumpkin seed extract could help improve the oxidative conditions of ovarian tissue. Pumpkin seed extract seems to be able to reduce the DNA damage to ovarian tissue due to its antioxidant effects. In the present study, there were limitations in the present study, including the study of animal specimens. Other limitations of this study include lack of measurement of other oxidant-prooxidant factors. According to the results, it seems that intervention of pumpkin seeds and aerobic training can help increase the balance of oxidant-prooxidant to improve mitochondrial biogenesis and reduce ovarian tissue DNA damage.