Radix Astragali, a Chinese medicinal herb, consists of
polysaccharides and
flavonoids as its main active ingredients. It has been widely used for treatment of
cardiovascular diseases such as
heart failure,
angina pectoris,
myocardial infarction and
stroke in Asian countries. This study was designed to evaluate the effect of
Radix Astragali on myocardial dysfunction, cardiac remodeling and morphological alteration in an experimental model of autoimmune
myocarditis, a clinical condition often resulting in
dilated cardiomyopathy. Experimental autoimmune
myocarditis was established with a
subcutaneous injection of porcine
cardiac myosin into rear footpad in Lewis rats.
Radix Astragali treatment was delivered via an
intravenous injection (0.2 ml/100g
body weight, daily) for 3 weeks. Results from transthoracic echocardiography indicated that experimental autoimmune
myocarditis led to impaired myocardial contractile function which was reconciled by
Radix Astragali. The experimental autoimmune
myocarditis triggered profound
inflammation and
fibrosis in myocardium as assessed by
hematoxylin and
eosin (H and E) and Masson's trichrome staining. Interestingly,
Radix Astragali significantly attenuated autoimmune
myocarditis-induced myocardial
inflammation and
fibrosis. Similarly,
Radix Astragali treatment alleviated autoimmune
myocarditis-triggered overt lymphocyte proliferation. Furthermore,
Radix Astragali significantly attenuated elevated levels of the Th1
cytokines (IFN-gamma and IL-2), and increased the Th2
cytokines (IL-4 and IL-10) in autoimmune
myocarditis. Collectively, our data revealed that
Radix Astragali effectively protected against cardiac functional and morphological aberrations in experimental autoimmune
myocarditis.