Background:
Exercise training could be essential in preventing
pathological cardiac remodeling in diabetes. Therefore, the effects of
moderate-intensity continuous training (MICT) and high-intensity interval
training (HIIT) singly or plus metformin on diabetes-induced cardiomyopathy were
investigated in this study.
Methods:
Forty-nine Wistar rats (male) were
recruited. Seven groups of animals were treated for six weeks as control,
diabetes, MICT (15 m/min, 40 min/day), HIIT (20 m/min, 40 min/day), metformin
(300 mg/kg), HIIT+metformin (Met-HIIT), and MICT+metformin (Met-MICT). The
metformin was orally administered with an intragastrical needle, and the
exercised rats were trained (5 days/week) with a motorized treadmill. Metabolic
parameters, echocardiographic indices, histopathology evaluation, and assessment
of gene expression connected with cardiac fibrosis, hypertrophy, mitochondrial
performance, and intracellular calcium homeostasis were investigated.
Results:
Our results demonstrated that all the interventions prevented
weight loss and enhanced heart weight/body weight ratio and fasting plasma
glucose in diabetic rats. Both types of exercise and their metformin combinations
improved diabetic animals’ echocardiography indices by enhancing heart rate,
fractional shortening (FS), ejection fraction (EF) and reducing end-systolic and
end-diastolic diameter of left ventricular (LVESD and LVEDD). Gene expression of
atrial natriuretic peptide
(
ANP
),
brain natriuretic
peptide
(
BNP
),
transforming growth factor
(
TGF
)
-
, and
collagen
increased in the
diabetes group. In contrast, the gene expression of
peroxisome
proliferator-activated receptor gamma coactivator 1 alpha
(
PGC-1
),
AMP-activated protein kinase
(
AMPK
),
ryanodine receptors
(
RyR
), and
ATPase pump of the sarcoplasmic reticulum
(
SERCA
) was
reduced in diabetic animals. Exercise training alone or in combination with
metformin reversed these changes. Moreover, diabetes-induced cardiac fibrosis was
ameliorated in treated groups. All indicators of diabetic cardiomyopathy were
improved more in the Met-HIIT group than in other groups.
Conclusions:
Exercise training, notably with metformin combination, alleviated
diabetes-induced cardiac complications. The beneficial effects of exercise could
be related to improving pathological cardiac remodeling and enhancing cardiac
function.