اثر شدت های مختلف تمرین در شرایط هیپوکسی و نرم اکسی بر محتوای چربی کبد، سلول های خونی و عملکرد استقامتی رت های نر دارای رژیم غذایی پرچرب

اهداف: در این مطالعه اثر شدت‌های مختلف تمرین در شرایط هیپوکسی و نرم‌اکسی بر محتوای چربی کبد و عملکرد استقامتی رت‌ها مورد بررسی قرار گرفت. مواد و روش‌ها: 48 رت نر نژاد ویستار با سن تقریبی پنج هفته‌ به‌صورت تصادفی در گروه‌های رژیم غذایی نرمال (nd)، رژیم غذای پرچرب (hfd)، رژیم غذای پرچرب و تمرین تداومی با شدت متوسط (hfd-mict)، رژیم غذای پرچرب و تمرین تداومی با شدت متوسط در شرایط هیپوکسی (hfd-hmict)، رژیم غذای پرچرب و تمرین تناوبی با شدت بالا (hfd-hiit)، رژیم غذای پرچرب و تمرین تناوبی با شدت بالا در شرایط هیپوکسی (hfd-hhiit) قرار گرفتند. پس از تعیین حداکثر سرعت هوازی در شرایط نرم‌اکسی (ارتفاع معادل 50 متر) و هیپوکسی (ارتفاع معادل 3000 متر) تمرینات به مدت 12 هفته و 3 جلسه در هفته اجرا شدند. نتایج: وزن، محتوای چربی کبد و تعداد لکوسیت‌ها در گروه hfd نسبت به‌تمامی گروه‌ها بالاتر و عملکرد استقامتی پایین‌تر بود (0.05>p). کمترین میزان افزایش وزن و محتوای چربی و بالاترین عملکرد استقامتی در گروه‌های hiit بود (0.05>p). عملکرد استقامتی در گروه‌های mict نسبت به گروه-های hiit کمتر بود. افزایش عملکرد هوازی در گروه‌های هیپوکسی مستقل از تغییرات rbc و hgb بود. mict در هیپوکسی در مقایسه با نرم‌اکسی مزایای بیشتری را در کاهش محتوای چربی کبد به همراه نداشت. نتیجه‌گیری: افزایش عملکرد استقامتی در گروه hfd-hhiit مستقل از تغییرات فاکتورهای خونی مرتبط با ظرفیت انتقال اکسیژن بود. احتمالاً مداخله این تحقیق به دلیل قرار گرفتن کوتاه‌مدت در معرض هیپوکسی تحریک کافی برای تغییرات خونی را القا نمی‌کند.

the effect of different exercise intensities in hypoxia and normoxia conditions on liver fat content, blood cells, and endurance performance of male rats under high-fat diet

extended abstract background and purpose non-alcoholic fatty liver disease (nafld) is a common clinical manifestation of metabolic syndrome, affecting both children and adults. it is estimated that up to 90% of obese individuals maydevelop nafld. this disease is strongly associated with various metabolic dysfunctions, including insulin resistance, oxidative stress, endoplasmic reticulum stress, and mitochondrial dysfunction. these factors contribute to the progression of nafld, making it an important concern in metabolichealth.despite a growing understanding of the underlying mechanisms of nafld, there is currently no approved pharmaceutical treatment available. given that cardiovascular issues are the leading cause of mortality in individuals with nafld, the adoption of regular aerobic exercise emerges as apromising strategy. aerobic exercise has been shown to reduce liver fat content and improve various cardiovascular risk factors, offering a non-invasive approach to managing both liver health and heart disease risk in these patients. vascular health and the enhancement of sports performance are important considerations for affected individuals. as aerobic fitness improves, the gains in endurance performance from training tend to diminish gradually. consequently, alternative methods, such as training or residing at high altitude in combination with sea-level training, have gained popularity as strategies to further boost endurance performance. however, research on hypoxia has yielded inconsistent findings regarding its impact on endurance performance. materials and methods the study involved 48 male wistar rats, each with an average weight of 165 grams and approximately five weeks of age. after acclimatizing to the environment and becoming familiar with the treadmill, the rats were randomly divided into six groups, with six rats per group. the groups were designated as follows: nd (normal diet), hfd (high-fat diet), hfd-mict (high-fat diet with moderate-intensity continuous training in normoxia), hfd-hmict (high-fat diet with moderate-intensity continuous training in hypoxia), hfd-hiit (high-fat diet with high-intensity interval training in normoxia), and hfd-hhiit (high-fat diet with high-intensity interval training in hypoxia). the exercise training intervention for the training groups lasted 12 weeks, with three sessions per week. during this period, the nd and hfd groups refrained from any physical activity. to simulate altitude training, the researchers used a hypoxia device that maintained the oxygen pressure at approximately 140 millibars, corresponding to an altitude of 3000 meters. tissue sampling and serum sample collection were conducted 48 hours after the completion of the nutritional and exercise training interventions. oil red o staining (ab 150678; lipid stain kit) was performed to assess the fat content in the liver. the number and area of fat droplets were evaluated using both optical and fluorescent microscopy with a germany-axiom bm-600 led epi fluorescent microscope and mshot microscope camera, analyzed with j image software. data analysis was conducted using spss version 26, with one-way analysis of variance (anova) and tukey's post hoc test applied at a significance level of p < 0.05 to assess statistical significance.findings the results revealed a consistent increase in the weight of rats across all groups. notably, the high-fat diet led to significant weight gain in the hfd, hfd+mict, and hfd+hmict groups compared to the nd group. however, the weight of rats in the hfd+mict and hfd+hmict groups was significantly lower than that of the hfd group (p < 0.01). no significant difference in weight was observed between the nd and hfd-hiit or hfd-hhiit groups.furthermore, the fat content in the liver of rats increased across all groups in comparison to the nd group. interestingly, exercise training effectively mitigated the increase in liver fat content comparedto the hfd group (p<0.005). additionally, hiit and hhiit were more effective in maintaining lipid droplet content at baseline levels compared to mict and hmict. specifically, only in the hfd-hiit and hfd-hhiit groups did the fat content show no significant difference from the nd group. moreover, no significant difference in fat content was observed between the hfd-hiit and hfd-hhiit groups.