Objective: To study the inhibitory effect of protoporphyrin disodium (NAPP) on human hepatoma carcinoma cell strain of SMMC-7721 cells in vitro . Method: The maximum atoxic concentration (TC0) of NAPP was determined by drug toxicity test on normal human hepatocyte strain of QSG-7701 cells. TC0 was used as the initial concentration

five different concentrations of NAPP were diluted by 10 times gradient dilution

and applied to treat the human hepatoma carcinoma cell strain of SMMC-7721 cells cultured in vitro . MTT assay was used for evaluating the proliferation inhibitory effect of NAPP. Morphological observation for SMMC-7721 cells was undertaken via the inverted optical microscope and inverted fluorescence microscope after Hoechst33258 staining. Apoptotic cells were counted and apoptosis index (AI) was calculated. Flow cytometry was applied to measure the apoptosis and necrosis rates of SMMC-7721 cells through Annexin V-FITC/PI double staining with apoptosis detection kit. Result: The proliferation of SMMC-7721 cells was inhibited dramatically after the treatment of different concentrations of NAPP

and the A values were decreased significantly (P<0.05 orP<0.01). The inhibition rate was depended on the concentration of NAPP and the treatment time to some extent. These were visible in the optical microscope that cell number reduced obviously

cell density was thinning markedly

the appearance of SMMC-7721 cells was changed evidently

significantly

many conjunctions between cells disappeared

and cells became round and corrugativus or cellular shape turned slender like Fusiform shape. The SMMC-7721 cell nucleus showed the typical changes of apoptosis morphology in fluorescence microscope

and AI increased remarkably (P<0.05 orP<0.01). Flow cytometry showed that apoptosis and necrosis rates of SMMC-7721 cells were raised to different level. Conclusion: NAPP can inhibit the proliferation of human hepatoma carcinoma cell strain of SMMC-7721 cells and promote its apoptosis and necrosis.