Caloric restriction, physical exercise, and CB1 receptor blockade as an efficient combined strategy for bodyweight control and cardiometabolic status improvement in male rats

www.nature.com/scientificreports OPEN Caloric restriction, physical exercise, and CB1 receptor blockade as an efficient combined strategy for bodyweight control and cardiometabolic status improvement in male rats Luisa M. Lopez Trinidad1,3, Rosario Martinez1,3, Garyfallia Kapravelou1, Milagros Galisteo2, Pilar Aranda1, Jesus M. Porres1* & Maria Lopez‑Jurado1 Obesity is critically associated with the development of insulin resistance and related cardiovascular and kidney diseases. Several strategies for weight loss have been developed but most of them exhibit a post-intervention rebound effect. Here, we aimed to design combined weight-loss strategies of caloric restriction, physical exercise, and administration of a CB1 receptor blocker to inhibit food intake that also accomplish the objectives of lost-weight maintenance and improvement of cardiovascular and renal function. Diet-induced obesity (DIO) was generated in Sprague Dawley rats for 12 weeks to test the effects of single or combined strategies (i.e. caloric restriction, mixed training protocol, and/or administration of appetite suppressant) on caloric intake, body weight, cardiovascular and renal functionality resulting from a weight-loss intervention period of 3 weeks followed by 6 weeks of weight maintenance. Consumption of a high-fat diet (HFD) caused a significant increase in body weight (5th week of the experimental period) and led to the development of insulin resistance, cardiovascular, and renal alterations. The different interventions tested, resulted in a significant body weight loss and improved glucose metabolism, aerobic capacity, electrocardiographic parameters, vascular expression of adhesion molecules and inflammatory mediators, and renal functionality, reaching values similar to the control normocaloric group or even improving them. Successful maintenance of lost weight was achieved along a 6-week maintenance period in addition to adequate health status. In conclusion, the weight-loss and maintenance intervention strategies tested were efficient at reversing the obesity-related alterations in body weight, glucose metabolism, aerobic capacity, cardiovascular and renal functionality. The beneficial action was very consistent for caloric restriction and physical exercise, whereas administration of a CB1 receptor blocker complemented the effects of the prior interventions in some parameters like body weight or aerobic capacity, and showed specific actions in renal status, increasing glomerular filtration rate and diuresis. Overall, the novelty of our study relies on the easy implementation of combined strategies for effective weight management that resulted in significant health benefits. Overweight and obesity are defined as abnormal or excessive fat accumulation that increases the risk to develop multiple pathologies. They lead to adverse metabolic effects on blood pressure, cholesterol, triglycerides, and insulin resistance. This compilation of factors is known as metabolic syndrome (MetS)1, which is directly related to cardiovascular disease and the alteration in other vital functions, such as the renal function2. Overweight, 1 Department of Physiology, Institute of Nutrition and Food Technology (INyTA), Centre for Biomedical Research, Centre for Research in Sport and Health (IMUDS), Universidad de Granada, Avda. del Conocimiento S/N. Armilla (18100), Granada, Spain. 2Department of Pharmacology, School of Pharmacy, Biohealth Research Institute, Centre for Biomedical Research, Universidad de Granada, Granada, Spain. 3These authors contributed equally: Luisa M. Lopez Trinidad and Rosario Martinez. *email: Scientific Reports | (2021) 11:4286 | https://doi.org/10.1038/s41598-021-83709-9 1 Vol.:(0123456789) www.nature.com/scientificreports/ ▸ Figure 1.  Effects of DIO and weight control interventions on caloric intake, body weight, body weight/ femur length ratio, and hypothalamic gene expression of transcripts involved in the central regulation of food intake and energy balance. Six control experiments were carried out during 21 weeks using a standard rat chow diet (SD12, SD15, and SD21) or a high-fat diet to induce obesity (HFD12, HFD15, and HFD21). For intervention trials, rats were divided into 8 groups that were fed the hypercaloric diet to induce obesity for 12 weeks, followed by three weeks of intervention with a high protein diet for weight loss (WL15) combined or not with the training protocol (e or s, respectively) and the pharmacological treatment with CB1 receptor blocker AM251 (AM). The intervention period was followed by an additional 6-week weight-maintenance period of dietary treatment with a standard rat chow diet (WM21) combined or not with the training protocol (e or s, respectively) and the pharmacological treatment (AM) to maintain the weight lost during the previous intervention period of three weeks. (A) Experimental design, (B) average daily caloric intake (kcal/day) along the different experimental stages (DIO, weight-loss intervention, and weight-maintenance), (C) average body weight at the end of the different experimental stages, (D) bodyweight/ femur length ratio (g/cm2) at the end of the different experimental stages, (E) hypothalamic gene expression at the end of the weight-loss intervention and weight-maintenance stages. Results are means of eight rats ± SEM depicted by vertical bars. ***P < 0.001 in t-test (12 weeks); A,B,C means with different letters are significantly different (ANOVA treatment, P < 0.05; 15 and 21 weeks). cfos c-Fos, npy neuropeptide Y, lepr leptin receptor, hcrt orexin A, cnr1 cannabinoid receptor. obesity and its related diseases are largely p reventable3. In this regard, a comprehensive understanding of MetS may be important for the adequate planning of prevention strategies. Since its components are all reversible, early diagnosis and lifestyle intervention strategies of MetS offer an effective treatment approach, primarily targeting weight management. The control and maintenance of the body weight at a stable level are achieved when there is a balance between food intake and energy expenditure. A complex physiological control system is involved in the maintenance of the energy balance and includes afferent signals from the periphery regarding the state of energy stores, as well as efferent signals affecting energy intake and expenditure4. This regulatory system includes multiple interactions between the gastrointestinal tract, adipose tissue and central nervous system, and is influenced by behavioral, sensorial, autonomic, nutritional and endocrine m echanisms5. The first step in the treatment of obesity is focused on losing the extra-weight and ameliorate the related metabolic alterations. Another important issue for subjects who complete a weight loss program is to avoid the post-intervention rebound effect. The bodyweight regain usually takes place right after the end of weight loss intervention as weight loss programs are jus (...truncated)