ABSTRACT
OBJECTIVE: To explore the effects of UVB and Nano-CaCO_3 co-treatment in inhibiting cell proliferation and inducing cell apoptosis in human HaCaT keratinocytes,and to explore its possible mechanisms. METHODS: HaCaT cells( logarithmic growth phase) were divided into control group,UVB group,Nano-CaCO_3 group and co-treatment group. UVB group and co-treatment group were irradiated with UVB irradiation with cumulative exposure dose of 2. 97 × 10~(-2)J / cm~2.Control group and Nano-CaCO_3 group were irradiated with UVB irradiation with cumulative exposure dose of zero on equal terms. After that,control group and UVB group were treated with 10. 00% phosphate buffer solution in high-sugar Dulbecco's modified Eagle's medium( DMEM) and incubated,Nano-CaCO_3 group and co-treatment group were treated with high-sugar DMEM with Nano-CaCO_3 at 250 mg / L mass concentration and incubated. Subsequently,HaCaT cells were harvested at incubation time of 0,6,12,18 and 24 hours. Then methyl thiazolyl tetrazolium assay was performed to estimate cellular proliferative activity,flow cytometry was used to detect cell apoptosis,Western blot was used to detect the expression of P53 and Caspases-3 protein. RESULTS: Contrast to control group at the parallel incubation time points of 6-24 hours,the cell viability of HaCaT cells was significant decreased in the other three groups( P < 0. 05) except for UVB group at incubation time of 6 hours( P > 0. 05). The cell viability of co-treatment group was lower than UVB group at all the incubation time( P < 0. 05),and lower than Nano-CaCO_3 group at incubation time of 18 and 24 hours( P < 0. 05).The apoptosis rate of HaCaT cells in UVB group was higher than control group( P < 0. 05),and which in co-treatment group was higher than the other three groups( P < 0. 05). Contrast to control group,the protein expressions of P53 and Caspases-3 in HaCaT cells were upregulated in UVB group and Nano-CaCO_3 group. In co-treatment group,the protein expressions of P53 and Caspases-3 were upregulated contrast to the other three groups. CONCLUSION: Contrast to single damage of UVB or Nano-CaCO_3,co-treatment of UVB with Nano-CaCO_3 increased damage to HaCaT cells,likely by inhibiting proliferative activity,inducing apoptosis,and enhancing protein expressions of P53 and Caspases-3.