Abstract: OBJECTIVE： To evaluate inhibitory effects of photodynamic therapy (PDT) on the cervical cancer cell lines，HeLa，with different Ki-67 expression levels. METHODS：HeLa cells with different Ki-67 expression levels were constructed by RNA interference technology： Blank control group， Negative control group (treated with negative control siRNA) and Ki-67 knockdown group (treated with Ki-67 siRNA). Western blot was used to detect Ki-67 protein expression to verify the knockdown effect. CCK8 assay and wound healing assay were used to assess cell proliferation rate and wound healing rate in each group. PDT treatment was performed on each group of cells (the cells in each group were incubated with 5-ALA photosensitizer at a concentration of 3 mmol/L for 6 hours under the conditions of laser wavelength 630 nm，energy 15 J/cm² ， and maximum output power 2 W). Morphological changes were observed post-PDT，and cell proliferation rate and wound healing rate were re-evaluated. RESULTS：Western blot analysis showed that the grayscale of the Ki-67 protein expression band in the Ki-67 knockdown group was weaker than that in the two control groups (P <0.05). CCK-8 assay results showed that the D(450) of the Ki-67 knockdown group was lower than that of the blank control group at each time point from day 1 to day 5 (P <0.05). The scratch test showed that the migration rate of the Ki-67 knockdown group was lower than that of the blank control group (P <0.05). After PDT treatment， the proliferation activity of the cells in the blank control group and the Ki-67 knockdown group was significantly decreased. On days 4 and 5，the proliferation inhibition rate of the cells in the Ki-67 knockdown group was higher than that in the blank control group (P <0.05). At 24 h after PDT treatment，the scratch test results showed that the migration rate of the cells in the blank control group and the Ki-67 knockdown group was decreased，and the decrease in the blank control group was more significant (P <0.05). After PDT treatment，morphological observations under a microscope showed that the cell morphology underwent changes similar to cell pyroptosis，including a decrease in cell volume，movement of the cell nucleus to the edge，and a large vesicle bulging out from the other side of the cell. CONCLUSION：PDT had an inhibitory effect on the proliferation and migration of cervical cancer HeLa cells，and its inhibitory effect on cells with high expression of Ki-67 was stronger. After PDT，cell morphology showed changes like those of pyroptosis.

Key words: photodynamic therapy, cervical cancer, Ki-67, HeLa cell