Effects of hydroxyapatite nanoparticles on proliferation and apoptosis of human hepatoma BEL-7402 cells

AIM: To study the effect of hydroxyapatite (HAP) nanoparticles on human hepatoma cell line BEL-7402 in vitro. METHODS: The human hepatoma cell line BEL-7402 was cultured and treated with HAP nanoparticles at various concentrations. Growth suppression was detected with MTT colorimetric assay, cell apoptotic alterations were evaluated by cytochemical staining (Hoechst 33258), transmission electron microscopy (TEM), and flow cytometry (FCM). RESULTS: HAP nanoparticles inhibited the growth of hepatoma cells in a dose-dependent manner, with IC(50) values of 29.30 mg/L. Treated with 50-200 mg/L HAP nanoparticles for 48 h, BEL-7402 cells apoptosis with nuclear chromatin condensation and fragmentation as well as cell shrinkage and the formation of apoptotic bodies were observed under cytochemical staining and transmission electron microscopy. FCM analysis showed hypodiploid peaks on histogram, the apoptotic rates at the concentrations of 50, 75, 100, 150 and 200 mg/L of HAP nanoparticles were 20.35+/-2.23 %, 25.35+/-1.92 %, 29.34+/-4.61 %, 44.92+/-3.78 % and 53.64+/-3.49 %, respectively, which were all significantly higher than that of control group 2.23+/-0.14 %. There was a significant correlation between HAP nanoparticle concentration and apoptotic rate (r=0.994, P<0.01). CONCLUSION: HAP nanoparticles not only inhibit proliferation but also induce apoptosis of human hepatoma cell line BEL-7402 in vitro.