Objective:

2

To investigate the effect of Tongmai Hypoglycemic Capsule (THC) on myocardium injury in diabetic cardiomyopathy (DCM) rats.

Methods:

2

A total of 24 Sprague Dawley rats were fed for 4 weeks with high-fat and high-sugar food and then injected with streptozotocin intraperitoneally for the establishment of the DCM model. In addition

6 rats with normal diets were used as the control group. After modeling

24 DCM rats were randomly divided into the model

L-THC

M-THC

and H-THC groups by computer generated random numbers

and 0

0.16

0.32

0.64 g/kg of THC were adopted respectively by gavage

with 6 rats in each group. After 12 weeks of THC administration

echocardiography

histopathological staining

biochemical analysis

and Western blot were used to detect the changes in myocardial structure

oxidative stress (OS)

biochemical indexes

protein expressions of myocardial fibrosis

and nuclear factor erythroid 2-related faactor 2 (Nrf2) element

respectively.

Results:

2

Treatment with THC significantly decreased cardiac markers such as creatine kinase

lactate dehydrogenase

and creatine kinase-MB

etc. (

P

<

0.01); enhanced cardiac function indicators including heart rate

ejection fraction

cardiac output

interventricular septal thickness at diastole

and others (

P

<

0.05 or

P

<

0.01); decreased levels of biochemical indicators such as fasting blood glucose

total cholesterol

triglycerides

low-density lipoprotein cholesterol

aspartate transaminase

(

P

<

0.05 or

P

<

0.01); and decreased the levels of myocardial fibrosis markers α-smooth muscle actin (α-SMA)

and collagen Ⅰ (Col-1) protein (

P

<

0.01)

improved myocardial morphology and the status of myocardial interstitial fibrosis. THC significantly reduced malondialdehyde levels in model rats (

P

<

0.01)

increased levels of catalase

superoxide dismutase

and glutathione (

P

<

0.01)

and significantly increased the expression of Nrf2

NAD(P)H:quinone oxidoreductase 1

heme oxygenase-1

and superoxide dismutase 2 proteins in the left ventricle of rats (

P

<

0.01).

Conclusion:

2

THC activates the Nrf2 signaling pathway and plays a protective role in reducing OS injury and cardiac fibrosis in DCM rats.