Resistance training restores metabolic alterations induced by monosodium glutamate in a sex‐dependent manner in male and female rats

Abstract

Despite resistance exercises being associated with health outcomes, numerous issues are still unresolved and further research is required before the exercise can faithfully be prescribed as medicine. The goal of this study was to investigate whether there are sex differences in resistance training effects on metabolic alterations induced by monosodium glutamate (MSG), a model of obesity, in male and female rats. Male and female Wistar rats received MSG (4 g/kg body weight/day, s.c.) from postnatal day 1 to 10. After 10 days from MSG administration, the rats were separated into two groups: MSG-sedentary and MSG-exercised. At postnatal day 60, the animals started a resistance training protocol in an 80 degrees inclined vertical ladder apparatus and performed it for 7 weeks. Control rats received saline solution and were divided in saline-sedentary and saline-exercised. Resistance training restored all plasma biochemical parameters (glucose, cholesterol, triglycerides, aspartate aminotransferase, and alanine aminotransferase) increased in male and female rats treated with MSG. The MSG administration induced hyperglycemia associated with a decrease in the skeletal muscle glucose transporter 4 (GLUT4) levels and accompanied by deregulation in proteins, G-6Pase, and tyrosine aminotransferase, involved in hepatic glucose metabolism of male and female rats. MSG induced dyslipidemia and lipotoxicity in the liver and skeletal muscle of male rats. Regarding female rats, lipotoxicity was found only in the skeletal muscle.The resistance training had beneficial effects against metabolic alterations induced by MSG in male and female rats, through regulation of proteins (GLUT2, protein kinase B, and GLUT4) involved in glucose and lipid pathways in the liver and skeletal muscle. K E Y W O R D S glucose metabolism, lipotoxicity, monosodium glutamate (MSG), resistance exercise, sex J Cell Biochem. 2019;120:13426-13440. wileyonlinelibrary.com/journal/jcb 13426 |

Regulation of Skeletal Muscle Glucose Transport and Glucose Metabolism by Exercise Training

“…In resistance training research studies, the most common form of exercise utilized with human subjects is a weight-bearing program involving the upper body, lower body and abdomen [8,9,10]. In contrast, in resistance training studies involving rodents the most common form of exercise is weighted ladder climbing [11,12,13,14]. While aerobic exercise training activities are naturally common in both humans and animals due to survival instincts (i.e., chasing down prey or running away from a predator), resistance exercise training activities (i.e., carrying an external load) are not.…”

“…In addition, studies in rodents have demonstrated similar beneficial effects of resistance training on systemic glucose control. These studies found the following effects: (1) 7 weeks of progressive weighted ladder climbing (80° incline, 10 climbs/session, 5 sessions/week starting with an external load equal to 10% body weight and increasing up to 70% body weight) decreased fasted blood glucose levels ~30% in monosodium glutamate diet-induced diabetic rats [13]; (2) 8 weeks of progressive weighted ladder climbing (85° incline, 10 climbs/session, 3 sessions/week starting with an external load equal to 50% body weight and increasing up to 80% max load) reduced fasted blood glucose levels ~55% and improved glucose tolerance 50% in diabetic Zucker fatty rats compared to sedentary controls [11]; and (3) 10 weeks of isometric wire hang training (3 min/bout, 3 bouts/session, 5 sessions/week) decreased blood glucose levels ~30% 2 hrs. following an intraperitoneal glucose challenge in high fat diet-induced hyperglycemic C57BL/6N mice compared to sedentary controls [58].…”

“…While 6 weeks of intense progressive resistance training increased GLUT4 protein levels ~40% in the vastus lateralis of men with type 2 diabetes [151], the same training regimen failed to significantly alter muscle GLUT4 protein content in the healthy controls [151]. In addition, in mouse rectus femoris muscle, 10 weeks of isometric resistance exercise training increased GLUT4 protein levels ~70% [58]; yet, no change in GLUT4 protein levels was observed in rat gastrocnemius following 7 weeks of progressive weighted vertical ladder climbing [13]. The findings suggesting no role for GLUT4 in resistance training-induced muscle glucose transport are supported by recent work in muscle-specific GLUT4 knockout mice that demonstrated no impairment in plantaris muscle glucose transport following 5 days of functional overload, a model of resistance exercise training [73].…”

Neuroprotector Effect Of Strength Training In An Neuroinflammation Animal Model

“…According to [46], the neuroprotective effects of three models of nonpharmaceutical intervention, environmental enrichment, muscular strength exercise and social enrichment were investigated in an animal model of Alzheimer's disease. The authors demonstrated that eight weeks of muscular strength exercise were able to revert the social and discriminative memory deficit after the intra-hippocampal infusion of the beta amyloid Aβ in Wistar mice.…”

The protective effect of Nigella sativa seeds against monosodium glutamate-induced hepatic dysfunction in rats

“…Although food safety regulatory organizations considered MSG consumption is not related to health hazard problems, several studies have confirmed its deleterious effects in relation to differences in dosage, route of administration, and duration of exposure ( Chakraborty, 2019 ; Smriga, 2016). Nevertheless, MSG-induced hepatic impairment is evident by the detrimental changes in tissue damage biomarkers, carbohydrate and lipid metabolic pathways, antioxidant profile, and histopathological features ( Eid et al, 2019 ; Elbassuoni et al, 2018 ; Quines et al, 2019 ).…”