ABSTRACT
<p><b>OBJECTIVE</b>To observe matrine-induced erythroid differentiation of K562 cells in relation to activation of the apoptotic pathway in vitro.</p><p><b>METHODS</b>K562 cells were cultured in the presence or absence of matrine at different concentrations for 4 days, and the morphological and ultramicrostructural changes of the cells were observed using inverted microscopy and transmission electron microscopy, respectively. The expression of apoptosis-related protein p27kip1 was detected by immunocytochemistry.</p><p><b>RESULTS</b>Compared to untreated K562 cells, the cells treated with matrine at 0.10 g/L exhibited apoptostic characteristics in the cellular morphology and ultramicrostructure, with the expression of p27kip1 protein upregulated in a concentration- and time-dependent manner.</p><p><b>CONCLUSION</b>Matrine-induced erythroid differentiation of K562 cells is associated with cell apoptosis, and upregulation of p27kip1 protein expression may play a crucial role in the process of apoptosis.</p>