Volume 29, Issue 10 (12-2022)                   RJMS 2022, 29(10): 258-267 | Back to browse issues page

Research code: ندارد
Ethics code: IR.UMSHA.REC.1397.528
Clinical trials code: ندارد

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Kharazmi universityDepartment of Exercise Physiology, Faculty of Physical Education & Sports Science, Kharazmi University, Tehran, Iran , reihaneh.mkhani@gmail.com
Abstract:   (861 Views)
Background & Aims: The preconception and during pregnancy periods are now thought to be critical for the long-term effects on fetal development and postnatal growth and may predispose offspring to phenotypic changes and multi-diseases later in life. Moreover, physical activity and different kinds of stress during pregnancy are two important maternal behavioral lifestyles that can influence in health or disease of mothers and fetuses. While there are still many questions about the optimum intensity of maternal exercise, exercise during pregnancy has been considered as a positive environmental factor in the prevention of chronic diseases in the next generation. Several pieces of research have shown the positive effects of short-term and long-term exercise on the gene expression of offspring. High-intensity interval training is a form of cardiovascular exercise in which short periods of intense exercise with less-intense recovery periods. Animal model studies recently highlighted which pregnant mothers could tolerate this intensity during pregnancy. It has recently been determined that the Sirtuins family has a cardioprotective role in the heart. There is evidence that Sirt6 protects the heart from developing diseases through negative regulation of the insulin growth factor (IGF) signaling in the myocardial cells. Therefore, the present study aimed to investigate the role of high-intensity maternal exercise before and during pregnancy on the expression of cardiac genes Sirt6 and IGF2 as factors of cardiac health in adult female offspring.
Methods: Twenty-four female Wistar rats which never experienced a pregnancy, aged 8 weeks, were randomly divided into three maternal groups; mothers sedentary (control group, n = 8), mothers who exercised only before pregnancy (n = 8), and mothers who exercised before and during pregnancy (n = 8). High-intensity interval training consists of running on the treadmill with the speed of 18m/min at 10˚ inclination for 3 mins (85–95% ofVO2max), switching with active recovery, and the speed of 13m/min (65% of VO2max) at 0˚ inclination for 5 days/week which is in accordance with the overload principle; the duration and number of bouts were increased every week. High-intensity-interval training was performed in two parts, the first part included six weeks of HIIT prior to pregnancy and then 3 weeks of HIIT during pregnancy. Two females with one male were mated for two days. After pregnancy, the animals were kept individually per cage to notice the birth process, number, and birth weight of pups. Then the offspring were allocated to pup groups according to their mother groups at the end of the breastfeeding duration (3 weeks old). Ten-week-old rats were anesthetized with Xylazine (3 mg/kg) and Ketamine (30 mg/kg) and the left ventricle was separated after whole blood extraction. The Sirt6 gene expression and IGF-2 gene expression were measured by the RT-PCR method and the data were analyzed by the one-way ANOVA method.
Results: The present study showed that there was no statistically significant in the sex birth weight (P = 0.246) of pup groups as previously published. Also, maternal HIIT did not lead to significant differences in the number of pups (P = 0.16) between different maternal groups. Maternal HIIT before and during pregnancy has effects on the Sirt6 gene expression (P=0.0001) in the heart of female offspring and has no significant effect on IGF-2 gene expression (P=0.268). 
Conclusion: The consequences of maternal exercise in offspring have been investigated as a positive maternal behavior during pregnancy. We have indicated in our previous study that maternal exercise before and during pregnancy has positive effects on the cardioprotective genes of male offspring’s hearts. In the present study, we broaden the investigation to determine the cardioprotective effect of maternal exercise in female offspring. Our finding indicated that maternal high-intensity interval training leads to an increase of Sirt6 mRNA in the female similar to male offspring. Scientific evidence supports a relationship between birth weight and postnatal health outcomes and mentions birth weight as a vital factor in adult multi-disease. Consistent with the previous study, our study showed that maternal high-intensity interval training did not affect the birth weight of offspring. The benefits of high-intensity interval training on the heart are the reduction of glucose consumption as a source of energy so high-intensity interval training compared to traditional moderate-intensity continuous training is a suitable way to promote heart health. It is well established that maternal exercise during pregnancy improves insulin sensitivity in adult offspring. One of the protective factors of maternal exercise is the decreased cardiac glucose uptake in offspring, but its molecular mechanism is not well understood. It is well-known that one of the important pathways of the cardioprotective effect of exercise is an activation of the Sirtuins family. It has been demonstrated that one of the intergenerational effects of exercise in cardiomyocytes is increasing Sirt6 in the neonatal heart. Therefore, one of the possible mechanisms to increase the expression of the SIRT6 gene observed in the present study to improve the cardiovascular health of offspring by maternal HIIT before and during pregnancy is to reduce glucose consumption as fuel and reduce metabolic pressure on the heart of offspring. Likewise, we indicated that maternal high-intensity training could increase Sirt6 in the heart of adult female offspring. Thus, the above findings suggest maternal high-intensity exercise is a positive maternal behavior before and during pregnancy, which can affect the health of the heart in the next generation.

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Type of Study: Research | Subject: Exercise Physiology

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