The Effect of Chlorhexidine on the Fluorescence of Dugesia tigrina in a Planarian Toxicity Fluorescent Assay

Eye irritation tests are conducted to determine the toxicity of chemicals in eye products that may be potentially harmful to humans, animals, and the environment. However, many ocular irritation tests are seen as inaccurate, unethical, and expensive. These issues suggest that there needs to be more research conducted on ocular irritation tests. The purpose of this study was to determine how chlorhexidine, an eye drop preservative, affects the fluorescence of Dugesia tigrina in a planarian toxicity fluorescent assay. This research will help determine if the planarian toxicity fluorescent assay is valid for evaluating eye irritants. It was hypothesized that higher concentrations of chlorhexidine would result in higher fluorescence in Dugesia tigrina than lower concentrations of chlorhexidine. The D. tigrina were put in 0%, 0.004% and 0.02% concentrations of chlorhexidine for one minute. Then, they were placed in sodium fluorescein for one minute and placed under UV light. Pictures were taken and the fluorescence was evaluated in ImageJ. A one-way ANOVA (F(5.36E-6, 0.0001) = 90.1261, p﹤0.0001) was conducted and one or more significant differences were found between the groups. A post-hoc Tukey Kramer test was used to determine where the differences were. Each concentration group was found to be significantly different from the others. The results supported the hypothesis that higher concentrations of chlorhexidine would result in higher fluorescence. These results indicate that the planarian toxicity fluorescent assay can be used to detect different concentrations of eye drop preservatives