Mechanokinetics of Muscle Fatigue Development in Soleus Muscles of Obese Rats
Document Type
Conference Proceeding
Publication Date
5-2024
Publication Title
Gastroenterology
Abstract
Introduction: Obesity is a risk factor for limitations in muscle performance. Recent modeling studies suggest myocyte damage caused by obesity results in disturbance in overall muscle force. The exact mechanism by which intramuscular fat affects the contractile performance of muscle remains unclear. In this study we used obese rats to model muscle fatigue to better understand the impact of obesity on the contractile mechanics of muscle. Methods: Experiments were carried out on 40 male albino Wistar rats. Animals were divided into two equal groups. Rats of ‘Control’ group were fed a standard chow diet, and rats of ‘Obesity’ group were fed a high-fat diet for 10 weeks. Biometric parameters were calculated for each rat at the end of the 10-week period. Rats were placed under anesthesia, the soleus muscle was dissected from the surrounding tissues, and the ventral roots at L4-L5 of the spinal cord were cut. Stimulation at the L4-L5 segments was carried out by electrical impulses of 2 ms duration, 50 s-1 frequency, with duration of stimuli 6 s generated by a pulse generator through platinum electrodes, with two external loads. Each animal underwent 20 series of stimulation signals by non-relaxation, followed by a relaxation period of 30 minutes. Levels of creatinine, creatine phosphokinase (CPK), and lactate dehydrogenase (LDH) were determined from the serum of rats. Fragments of soleus muscles were analyzed histologically after the experiment. Results: The biometric profiles of both groups of rats were recorded after 10 weeks, and the obese rats had a significant increase in all recorded values (Table 1). On histology, lipid dystrophy and fibrosis were evident in obese rats. There was a significant increase in the time needed to return to initial level of contraction after stimulation in the obesity group when compared to the control group. The time needed to return to the initial state for each rat at both external loads, as well as maximal contraction forces as a percentage of the control group data was recorded (Figure 1). There was no difference in strength response in the control animals. Prolonged periods of complete tetanus were also found in obese rats when compared to control. Blood creatinine concentration, CPK, and LDH were all significantly elevated in obese rats after development of skeletal muscle fatigue in animals when compared to controls. Conclusion: Obesity is associated with limitations in the musculoskeletal system. Our study showed this at a histological and functional level. The lower contraction force may be explained by higher levels of inflammation, since fat deposits can increase inflammatory cytokines. This is confirmed by increased levels of creatinine, CPK and LDH. The study showed inclusion of intramuscular fat caused changes in muscular tissues with disturbances in the biochemical parameters and had effects on muscle activity.
Volume
166
Issue
5 Suppl
First Page
S587
Last Page
S588
Recommended Citation
Kozyk M, Nozdrenko D, Kalmukova O, Raksha N, Halenova T, Savchuk O, et al. [Struchevska K, Kessler S]. Mechanokinetics of muscle fatigue development in soleus muscles of obese rats. Gastroenterology. 2024 May;166(5 Suppl):S587-S588. doi: 10.1016/S0016-5085(24)01820-1
DOI
10.1016/S0016-5085(24)01820-1
Comments
DDW Digestive Disease Week, May 18-21, 2024, Washington, DC