Abstract: Objective To establish and improve Balb/c 3T3 mouse fibroblast neutral red uptake phototoxicity test (3T3 NRU-PT) method for detecting potential phototoxicity in the safety assessment. Method According to the guidelines for the testing of chemicals 432 (OECD), Balb/c 3T3 cell was incubated in 96-well plate, SDS, 8-MOP and CPZ were detected as the test substances. Biospectra system (France) was used as the UV radiation source, and the wavelength was 365nm. The potential phototoxicity was evaluated in a prediction model in which either the photo irritation factor (PIF) or the mean photo effect (MPE) were determined by Photo32 (Version 2.0). Result (1) when the irradiated dosage attained 5 to 20J/cm2, the relative survival rate gradually reduced; (2) The results of 3T3-NRU PT showed the value of PIF and MPE were 0.89、22.81、17.60 and 0.001、0.706、0.502 for SDS, 8-MOP and CPZ, respectively, according to the test threshold, SDS has no phototoxicity, 8-MOP and CPZ has obvious phototoxicity. Conclusion The 3T3-NRU PT was successfully established in our laboratory, and we took some improvements in the UV source choice and irradiation time, it may be a good method for evaluating the potential phototoxicity in safety assessment in future.

Key words: fibroblasts