[Study on cytotoxicity of microdoses peracetic acid in vitro].

Objective: To evaluate the cytotoxicity of microdoses peracetic acid (PAA) so as to provide the evidence for making residual limit of PAA sterilization.
Methods: Mouse fibroblasts (L929 cell line) cultured in vitro were observed to evaluate the influence of microdoses PAA including 1 x 10(-6), 2 x 10(-6), 3 x 10(-6), 4 x 10(-6), 5 x 10(-6), and 10 x 10(-6) (V/V). The proliferation of cells was determined by MTT assay at 2, 4, and 7 days of culture. The growth curve and the relative growth rate (RGR) were obtained. The cytotoxicity of PAA at different concentrations was evaluated according to RGR.
Results: At 2, 4, and 7 days after culture, fibroblasts of 1 x 10(-6) group grew with normal morphology analogous to control group, while the cell growth of other groups were poor. With the increase of PAA concentration, the absorbance (A) values decreased, which suggested that there was a significant negative correlation between cell proliferation and PAA concentration. And the correlation coefficient was -1.000 at 2 and 4 days, - 0.964 at 7 days. There was no significant difference in A value between 1 x 10(-6) group and the control group (P > 0.05), while there were significant differences in A value between the control group and other concentration groups (P < 0.05). The growth curve of 1 x 10(-6) group was similar to that of the control group, both had obvious phase of exponential growth. The growth curves of other groups had no obvious phase of exponential growth. The cytotoxicity of 1 x 10(-6) group was classified as level 1, 2 x 10(-6) group as level 2, 3 x 10(-6) group as level 3, 4 x 10(-6) group as level 3-4, 5 x 10(-6) group and 10 x 10(-6) group as level 4.
Conclusion: PAA of 1 x 10(-6) had no obvious cytotoxicity. The residual limit of PAA less than 1 x 10(-6) was recommended.