Objective  To study the adriamycin (ADR)-induced expression of ErbB4 in and apoptosis of cardiac muscle cells of rats with dilated cardiomyopathy and their intervention with neuregulin-1β.   Methods  Sixty male SD rats

weighing 200-250 g

were randomly divided into ADR 1 group (n=10)

ADR 2 group (n=20)

ADR+neuregulin-1β group (n=20)

and normal control (NC) group (n=10). Rats in ADR1 and ADR2 groups were injected with 2.0 mg/kg of ADR through the tail vein

once a week for 8 and 12 weeks

respectively. Rats in ADR+neuregulin-1β group were injected with 2.0mg/kg of ADR through the tail vein

once a week for 8 weeks

followed by neuregulin-1β [10 μg/(kg·d)]

once a day for 5 d. Rats in NC group received normal saline [2 ml/(kg·d)]

once a week for 8 weeks. Expression of ErbB4 was detected by Western blotting. Lesions of cardiac muscle were scored with HE staining. Apoptosis of cardiac muscle cells was detected with the TUNEL method.   Results  The apoptotic index of cardiac muscle cells was significantly lower in ADR+neuregulin-1β group than in ADR 1 group (P0.05). The expression level of ErbB4 was significantly higher in ADR 1 group than in NC group and obviously lower in ADR 2 group than in NC group

and significantly higher in ADR+neuregulin-1β group than in ADR2 group (P0.05).   Conclusion  Early ErbB4 expression increases in cardiac muscle cells of rats with dilated cardiomyopathy and decreases with the prolonged disease course. Neuregulin-1β can inhibit the apoptosis of and increase the ErbB expression in cardiac muscle cells.