RESUMO
OBJECTIVE: To study the effects of astragaloside on the expression of insulin-like growth factor-1 (IGF-1) and associated proteins in mice with viral myocarditis. METHODS: Sixty-five 4-week-old BALB/C mice were randomly divided into 5 groups: normal control, astragaloside control, untreated myocarditis, low-dose and high-dose astragaloside-treated myocarditis. The BALB/C mice in the later three groups were intraperitoneally injected with CVB3. The low-dose and high-dose astragaloside-treated myocarditis groups were given astragaloside of 0.07 and 0.6 mg/kgâ¢d, respectively by intragastric administration. Fifteen days later, the samples of blood and muscular tissues were obtained. The expression of IGF-1 in plasma was measured using ELISA. The levels of IGF-1 and associated proteins in muscular tissues were measured by immunohistochemistry. The expression of IGF-1 mRNA in muscular tissues was examined by RT-polymerase chain reaction (RT-PCR). RESULTS: The expression of IGF-1 and associated proteins increased significantly in mice infected with CVB3. High-dose astragaloside treatment reduced the expression of IGF-1 and associated proteins, but low-dose astragaloside did not. CONCLUSIONS: High-dose astragaloside may reduce the expression of IGF-1 and associated proteins in mice with acute viral myocarditis, possibly thus providing protective effects on muscular tissues.