نوع مقاله : مقاله پژوهشی
نویسندگان
1 دانشجوی دکتری فیزیولوژی ورزش، دانشکده فرهنگ و ارتباطات، واحد کرج، دانشگاه آزاد اسلامی، کرج، ایران.
2 استادیار گروه فیزیولوژی ورزش، دانشکده فرهنگ و ارتباطات، واحد کرج، دانشگاه آزاد اسلامی، کرج، ایران.
3 دانشیار گروه فیزیولوژی ورزش، دانشکده فرهنگ و ارتباطات، واحد کرج، دانشگاه آزاد اسلامی، کرج، ایران.
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
Extended Abstract
Background and Aim: Obesity, resulting from a chronic imbalance between energy intake and energy expenditure, is widely increasing and is considered a major risk factor for numerous pathological conditions. Excessive energy intake—particularly from high fat diets—leads to abnormal accumulation of triglycerides (TG) within hepatocytes, promoting hepatic steatosis and the development of non-alcoholic fatty liver disease (NAFLD). Obesity often leads to chronic low-grade inflammation, increased insulin resistance, and metabolic disorders in adipose tissue and liver. The CD28 protein acts as a co-stimulatory receptor essential for the full activation of T lymphocytes and plays an important role in the induction of low-grade inflammation in obesity. Exercise is considered a major regulator of liver metabolism by stimulating beta-oxidation and reducing lipogenesis. Studies have shown that choline and betaine supplementation can reduce hepatic steatosis by reducing hepatic and blood TG levels and stimulating lipolysis. Given the established benefits of aerobic exercise in improving hepatic lipid metabolism and inflammatory status, along with emerging evidence supporting the fat-reducing and anti-inflammatory effects of betaine, a combined intervention may exert synergistic benefits. These effects may be mediated, at least in part, through modulation of inflammation-related pathways, particularly CD28 signaling. However, the interactive effects of aerobic exercise and betaine supplementation on these parameters in obesity remain largely unexplored, and existing findings regarding their independent effects are inconsistent. Therefore, the present study aimed to investigate the combined effects of moderate-intensity interval training and nanoemulsified betaine supplementation on hepatic CD28 gene expression, serum urea and creatinine levels, and lipid profile in obese mice.
Materials and Methods: In this experimental study, 25 male Wistar rats (8 weeks old; body weight 270±20 g) were housed in special cages in an environment with an average temperature of 22±1.4 °C, humidity of 55±4%, and a light-dark cycle of 12:12 h. All animals had free access to water and special rat food. They were then randomly divided into 5 groups (5 rats in each group) including healthy, obese, obese+supplement, obese+exercise, and obese+supplement+exercise. Obesity was induced by feeding the designated groups a high-fat, high-cholesterol diet for 12 weeks. To confirm obesity induction, blood samples were collected from the tail vein at the end of the dietary intervention and prior to the commencement of exercise and supplementation protocols. Following obesity induction, rats in the exercise groups performed moderate-intensity interval aerobic training on a motorized treadmill for 8 weeks, 5 days per week, with progressive overload. During the first week, the protocol consisted of 10 intervals of 1-min running at 10 m/min, interspersed with 2-min active recovery at 5 m/min. Running speed during the work intervals was gradually increased, reaching 16 m/min by weeks 4–8. Nanoemulsified betaine was prepared using high-amplitude ultrasonication to enhance serum stability and bioavailability. The supplement was administered via oral gavage at a dose of 50 mg/kg body weight prior to each exercise session. Rats in the obese+supplement+exercise group received both interventions. At the end of the intervention period, hepatic tissue samples were collected for analysis of CD28 gene expression using quantitative real-time PCR (qRT-PCR). Serum lipid profile, including total cholesterol (TC), TG, low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C), was measured using standard enzymatic assays. Serum urea and creatinine levels were also assessed as indicators of renal function. Data were analyzed using independent t, two-way ANOVA, and Bonferroni post hoc tests at a significance level of p≤0.05.
Results: Independent t-test analysis demonstrated that obesity significantly increased hepatic CD28 gene expression, TG, TC, LDL-C, and creatinine (p=0.0001) serum, as well as urea levels (p=0.02), while significantly decreasing HDL-C levels (p=0.0001). Two-way ANOVA results (Table 1), followed by Bonferroni post hoc tests, revealed that 8 weeks of moderate-intensity interval training significantly reduced CD28 gene expression in obese rats (p=0.0001). This training intervention also resulted in significant reductions in TG, TC, LDL-C, and creatinine (p=0.0001), as well as urea (p=0.002) levels, accompanied by a significant increase in HDL-C (p=0.01). Similarly, supplementation with nanoemulsified betaine led to a significant decrease in CD28 gene expression (p=0.0001), TG, TC, LDL-C, and creatinine levels (p=0.0001), along with a significant increase in HDL-C (p=0.01). However, nanoemulsified betaine supplementation did not significantly affect serum urea levels in obese rats. Furthermore, two-way ANOVA and Bonferroni post hoc analyses indicated a significant interaction effect between moderate-intensity interval training and nanoemulsified betaine supplementation on CD28 expression (p=0.04), LDL-C (p=0.0001), TC (p=0.0001), and creatinine (p=0.005) levels. No significant interaction effect was observed for serum urea levels.
Conclusion: The findings of the present study demonstrate that interval aerobic training and nanoemulsified betaine supplementation, each alone, reduced TG, TC, LDL-C levels and increased HDL-C. Aerobic training (especially moderate intensity) increases muscle TG utilization and leads to improved fat oxidation. In addition, nanoemulsified betaine supplementation effectively reduced hepatic and circulating TG levels, likely through the stimulation of lipolysis and hepatic β-oxidation, which may attenuate fat accumulation in the liver of obese subjects. The results further indicate that both interval aerobic training and nanoemulsified betaine supplementation, individually and synergistically, significantly reduced CD28 gene expression, a key marker associated with obesity-related inflammation. The underlying mechanisms through which the combined intervention exerts its beneficial effects on fat mass and inflammatory status may involve improved regulation of lipid metabolism, reduced insulin resistance, and enhanced mitochondrial function. Notably, the combined application of moderate-intensity interval training and nanoemulsified betaine supplementation was particularly effective in modulating CD28 gene expression, highlighting its potential role in attenuating inflammatory signaling pathways associated with obesity. Furthermore, the significant improvements in lipid profiles and the reduction in serum creatinine levels support the modulatory effects of this combined intervention on obesity-induced metabolic disturbances and renal dysfunction. Overall, the observed interactive effects between exercise training and nanoemulsified betaine supplementation suggest that this combined approach may serve as a safe, practical, and non-pharmacological strategy for the prevention and management of metabolic complications associated with obesity through the modulation of metabolic pathways and inflammation-related cellular signaling.
Ethical Considerations: Ethical approval was obtained from the Ethics Committee of Islamic Azad University, Karaj Branch (Code: IR.IAU.K.REC.1403.65).
Funding: This research received no external funding. All study-related costs were covered by the researcher.
Conflict of Interest: The authors declare no conflicts of interest
کلیدواژهها [English]
)