Enhanced exercise-induced muscle damage and muscle protein degradation in streptozotocin-induced type 2 diabetic rats.
Aims/Introduction:  The effects of 5-day voluntary exercise on muscle damage and muscle protein degradation were investigated in a streptozotocin-induced rat model of moderately glycemic, uncontrolled, type 2 diabetes.


METHODS
In the preliminary experiment, an oral glucose tolerance (1.0 g/kg) test was carried out to confirm the development of diabetes 3 days after streptozotocin treatment (30 mg/kg). In the genuine experiment, rats were divided into four groups: (i) non-diabetic rats without exercise (controls); (ii) non-diabetic rats with exercise; (iii) diabetic rats without exercise; and (iv) diabetic rats with exercise. After 5 days of voluntary wheel running exercise, blood and 24-h urine were collected, and levels of serum creatine kinase, a marker of muscle damage, and 24-h urinary excretion of muscle degradation products were determined.


RESULTS
Type 2 diabetic rats with insulin deficiency that exercised had higher serum creatine kinase and greater urinary excretions of creatinine, urea nitrogen and 3-methylhistidine compared with both type 2 diabetic rats with insulin deficiency and non-diabetic rats that did not exercise. However, there were no differences in serum creatine kinase and urinary excretions of creatinine, urea nitrogen and 3-methylhistidine between non-diabetic rats that did and did not exercise.


CONCLUSIONS
These findings suggest that muscle damage is induced and muscle protein degradation are enhanced by chronic moderate exercise in moderately glycemic uncontrolled type 2 diabetic rats with insulin deficiency at an intensity level of exercise that does not affect muscle damage and muscle protein degradation in non-diabetic rats. (J Diabetes Invest, doi: 10.1111/j.2040-1124.2011.00130.x, 2011).
Department of General Medicine, Juntendo University School of Medicine.
Hirohide
H
Yokokawa
Department of Nutrition, Faculty of Home Economics, Kyoritsu Women's University, Tokyo.
Ikiko
I
Kinoshita
Department of Nutrition, Faculty of Home Economics, Kyoritsu Women's University, Tokyo.
Takeo
T
Hashiguchi
Department of Nursing and Department of Nutrition, Faculty of Health Care, Kiryu University, Midori.
Masako
M
Kako
Department of Nursing and Department of Nutrition, Faculty of Health Care, Kiryu University, Midori.
Kahoru
K
Sasaki
Department of Nutrition, Faculty of Health Science, Chukyo Women's University, Nagoya.
Akira
A
Tamura
Department of Food Science, Faculty of Dairy Science, Rakuno Gakuen University, Ebetsu, Japan.
Yuri
Y
Kintaka
Department of Nursing and Department of Nutrition, Faculty of Health Care, Kiryu University, Midori.
Yoko
Y
Suzuki
Department of Nursing and Department of Nutrition, Faculty of Health Care, Kiryu University, Midori.
Noriko
N
Ishizuka
Department of Nursing and Department of Nutrition, Faculty of Health Care, Kiryu University, Midori.
Katsumi
K
Arai
Department of Nursing and Department of Nutrition, Faculty of Health Care, Kiryu University, Midori.
Yoshiko
Y
Kasahara
Department of Nursing and Department of Nutrition, Faculty of Health Care, Kiryu University, Midori.
Mikiko
M
Kishi
Department of Nursing and Department of Nutrition, Faculty of Health Care, Kiryu University, Midori.
Yoko
Y
Kobayashi
Department of Nursing and Department of Nutrition, Faculty of Health Care, Kiryu University, Midori.
Tosei
T
Takahashi
Department of Nursing and Department of Nutrition, Faculty of Health Care, Kiryu University, Midori.
Hiroyuki
H
Shimizu
Department of Nursing and Department of Nutrition, Faculty of Health Care, Kiryu University, Midori.
Shuji
S
Inoue
Exercise; Muscle damage; Type 2 diabetes mellitus