Astragaloside Antagonizes The Damage Effects Of Cadmium On Cardiomyocyte In Rat

Objective:To investigate the effect of cadmium（Cd） on the cellviability, intercalated disc ultrastructure, expression of Connexin43（Cx43）and levels of Cx43mRNA in rat cardiomyocytes, and the protectionmechanism of astragalosideⅣ （AsⅣ） on it.Method:①The primary culture cardiomyocytes were obtained from1³days old SD neonatal rat ventricular tissue, and were identified byinvert microscope, electron microscope observation, H-E staining andimmunofluorescence. Then, the primary cultrue cardiomyocytes treatedwith Cd or Cd+AsⅣ were used for MTT andelectron microscopeobservation.②21SD rats were randomly divided into3group: controlgroup, Cd group(rats were treated with Cd1mg·d^-1·kg^-1body weight byintraperitoneal injection), Cd+AsⅣ group(the dose of cadmium was1mg·d^-1·kg^-1body weight, the dose of AsⅣ were respectively5mg·d^-1·kg^-1body weight and10mg·d^-1·kg^-1body weight). The rats after treatment1week or2weeks were anesthetized for thoracotomy, the ventricular tissuewere respectively adopted for light, electron microscope observation,immunohistochemistry and RT-qPCR. Results：①The primary culture cardiomyocytes were irregularfusiform or polygon by light microscope observation. The electronmicroscope observation showed that oblong cardiomyocytes, obviousnucleus, abundant mitochondria, Golgi bodies and endoplasmic reticulum.At high magnification, staggered myofilament and Z line material werefound in cardiomyocytes.24h MTT assay showed that The cell viabilitywas significantly reduced in Cd group compared with control group，and itwas significantly higher in Cd+AsⅣ group than Cd group. Undertransmission electron microscope, swelled mitochondria and dilatedendoplasmic reticulum were found in Cd group, while those were improvedin Cd+AsⅣ group compared with Cd group.②In Cd group,cardiomyocyte and intercalated disc ultrastructure were both damaged, andthe expression of Cx43was significantly reduced; the mRNA level ofCx43was also lower than control group by RT-qPCR detection; howeverthose in Cd+AsⅣ group were improved when compared with Cd group.Conclusion: Cadmium can affect the cell viability and morphology ofprimary culture cardiomyocytes, and injury intercalated disc ultrastructure,inhibit expression and transcription of Cx43in vivo; As Ⅳantagonizes thedamage effects of cadmium on cardiomyocyte in rats.