Exercise can reduce fibrosis in the myocardia of mice modeling type 2 diabetes
10.3760/cma.j.cn421666-20240106-00014
- VernacularTitle:运动对2型糖尿病小鼠心肌中促纤维化基因的影响
- Author:
Ting WANG
1
;
Yujiang LI
;
Yawen YE
;
Xiaoli QIAN
;
Li WANG
;
Haili CHEN
;
Shengcun LI
Author Information
1. 温州医科大学附属第二医康复医学中心，浙江省针灸康复重点实验室，温州 325027
- Publication Type:Journal Article
- Keywords:
Exercise;
Diabetes;
Cardiomyopathy;
miR-344g-5p genes;
Fibrosis
- From:
Chinese Journal of Physical Medicine and Rehabilitation
2025;47(6):481-486
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To observe the effect of exercise-regulated miR-344g-5p on the fibrosis-related SMAD genes and transforming growth factor beta (TGF-β) in the myocardia of mice modeling diabetes.Methods:Twenty-four male C57BL/6 mice (6-8 weeks old) were randomly divided into a control group ( n=12) and a type 2 diabetes group ( n=12). Each group was further divided into two subgroups based on exercise status to form a sedentary control group, an exercise control, a sedentary type 2 diabetes group and an exercise type 2 diabetes group with six mice in each subgroup. The control groups were fed a normal diet, while the type 2 diabetes groups were on a high-fat diet for 12 weeks. Type 2 diabetes was then induced by intraperitoneal injection of streptozotocin. Two weeks later, the exercise groups began 40 minutes of daily swimming training, five days a week for eight consecutive weeks. Right after that, their cardiac function was measured using a small animal ultrasound system and the derived ejection fraction (EF) and the maximal early (E) and late (A) transmitral velocities ratio (E/A ratio) in diastole. They were then sacrificed and myocardial tissue was resected and stained with Sirius red. The expression of miR-344g-5p in the myocardium was detected using quantitative polymerase chain reactions. The expression of phosphorylated SMAD3 (p-SMAD3) and TGF-β were assessed using western blotting. The Target Scan database was exploited to analyze whether there were predicted targets of miR-344g-5p and pro-fibrotic genes such as SMAD3, TGFBR2, COL1A2 and COL12A1, and to determine any correlations in the gene regulation. Results:After 22 weeks, the EF and E/A ratio in the sedentary type 2 diabetes group were (57.5±4.1)% and (1.4±0.3), respectively, both significantly lower than in the other groups. Myocardial collagen fibers in the sedentary type 2 diabetes group were significantly more abundant than in the sedentary control and exercise type 2 diabetes groups. And miR-344g-5p expression in the myocardia of the exercise type 2 diabetes group was significantly greater than that in the sedentary type 2 diabetes group. The expression of p-SMAD3 and TGF-β in the myocardia of the sedentary type 2 diabetes group was significantly higher than in the sedentary control and exercise type 2 diabetes groups. Target Scan analysis revealed that miR-344g-5p had potential binding sites with several fibrosis-related genes such as SMAD3, TGFBR2, COL1A2, and COL12A1. Based on the reduction in TGF-β and p-SMAD protein expression in the exercise type 2 diabetes group, it was hypothesized that miR-344g-5p may inhibit the post-transcriptional processes of those genes.Conclusions:Exercise promotes the recovery of diabetic cardiomyopathy by upregulating myocardial miR-344g-5p expression, which subsequently targets and suppresses p-SMAD3 and TGF-β protein expression, thereby reducing diabetic myocardial fibrosis.
