[Effect of nimodipine on mechanisms of HL-60 cell apoptosis induced by cytarabine].

The aim was to study the mechanisms of HL-60 cell apoptosis induced by nimodipine (NMDP) and cytarabine (Ara-C). The DNA fragment was detected by agarose gel electrophoresis. The expressions of bcl-2 and bax gene proteins related with apoptosis were investigated by immunohistochemistry. The results showed that HL-60 cell apoptosis rate had been increasing in the experimental groups compared with the control group since culturing 8 hours. The expression of Bcl-2 protein was lower and the expression of Bax protein was higher in the experimental groups than that in the control group, while ratio of bcl-2/bax was lower in the experimental groups than that in the control group. It is concluded that NMDP and Ara-C induce apoptosis of HL-60 cells, and the mechanism of apoptosis induced by them may down-regulate the expression of bcl-2 gene and up-regulate the expression of bax gene. The mechanism of HL-60 cell apoptosis induced by Ara-C and NMDP is probably associated with the down-regulation of Bcl-2 protein expression.

[Study on mechanism of apoptosis of HL-60 cells induced by cytarabine].

To study the mechanism of apoptosis of HL-60 cells induced by cytarabine (Ara-C), morphological changes of the HL-60 cells stained with Giemsa were observed by microscopy; the DNA fragments were detected by agarose gel electrophoresis; the expressions of Bcl-2 and bax gene-related apoptosis were investigated by immunohistochemistry. The results showed that HL-60 cells in experimental groups had changed in morphology since they were cultured for 8 hours. HL-60 cells stained with Giemsa showed that their nuclear membranes were splitted. The purplish red chromatins were concentrated into pieces and apoptosis bodies were formed. The apoptosis rate increased in the experimental groups compared with the control group. The expression of Bcl-2 protein was lower and the expression of Bax protein was higher and the ratio of Bcl-2/Bax proteins in the experimental groups was lower than those in the control group. It is concluded that Ara-c can effectively induce apoptosis of HL-60 cells and simultaneously decrease the level of expression of Bcl-2 protein and elevate the level of expression of Bax protein. Decrease of expression ratio of Bcl-2/Bax proteins may be one of the main mechanisms in HL-60 apoptosis induced by Ara-C.