1. The influence of aging on the effectiveness of heat stress in preventing disuse muscle atrophy
- Author
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Y. Kondo, Jiro Nakano, Jyunya Sakamoto, Yuichiro Honda, Minoru Okita, Tomoki Origuchi, and Hideki Kataoka
- Subjects
Male ,0301 basic medicine ,Aging ,medicine.medical_specialty ,Muscle Fibers, Skeletal ,03 medical and health sciences ,0302 clinical medicine ,Physiology (medical) ,Internal medicine ,medicine ,Animals ,HSP70 Heat-Shock Proteins ,Rats, Wistar ,Aging effect ,Muscle, Skeletal ,business.industry ,Hyperthermia, Induced ,Muscular Disorders, Atrophic ,Rats ,Heat stress ,Hsp70 ,Treatment Outcome ,030104 developmental biology ,Endocrinology ,Disuse muscle atrophy ,business ,Heat-Shock Response ,030217 neurology & neurosurgery - Abstract
This study examined the aging effect on disuse muscle atrophy prevention using heat stress. Wistar rats aged 7 and 60 weeks were divided into three groups as follows: control, immobilized (Im), and immobilized and heat stressed (ImH). Heat stress was given by immersing the hindlimbs in hot water (42 °C) for 60 min, once in every 3 days and the gastrocnemius (GAS) and soleus (SOL) muscles were extracted after 14 days. Muscle-fiber types were classified using ATPase staining. Heat shock protein 70 (HSP70) was assessed through Western blotting. In GAS muscle of both groups and SOL muscle of 7-week-old rats, the fiber diameter of each muscle type in the ImH group significantly increased compared with that in the Im group. However, this could not be observed in the SOL muscle of the 60-week-old rats. The increased percentage of type-I fibers and variability of types I and II muscle-fiber diameter were evident in the SOL muscle of the 60-week rats. HSP70 was significantly elevated in the ImH group compared with in the Im group in both muscle types of both age groups. Thus, effectiveness of heat stress in the prevention of disuse muscle atrophy appears unsatisfactory in aging muscle fibers.
- Published
- 2017