Data obtained from in vitro investigations of curcumin-mediated Photodynamic Therapy (PDT) are encouraging, but the lack of reliable in vivo evidence has not allowed this method to be confirmed as an effective therapy for oral candidiasis. Thus, this study describes the photoinactivation of Candida albicans in a murine model of oral candidiasis, using curcumin as a photosensitizer.
Method:
Forty five Swiss mice were immunosuppressed, provided tetracycline to their drinking water, and then orally inoculated with a suspension of C. albicans. Five days after oral inoculation, animals belonging to P+L+ groups (animals treated with PDT) received a topical administration of curcumin (20, 40 and 80µM) and illumination with LED light at 37.5J/cm2 (455nm). The use of curcumin or light alone were also investigated (P+L- and P-L+ groups, respectively). Positive control animals did not receive any treatment (P-L- group) and negative control animals were not inoculated with C. albicans. After swabbing to recover yeast from the tongue, the number of surviving yeast cells was determined (CFU/mL) and analyzed by ANOVA and Tukey's post-hoc tests (α=0.05). Animals were humanely killed, the tongues surgically removed and processed for histological evaluation of presence of yeast and inflammatory reaction.
Result:
All associations of curcumin with LED light were able to significantly reduce C. albicans viability after PDT, when compared with the log(CFU/mL) value of P-L- group. The use of 80µM associated with LED light was able promoted the highest log10 reduction in colony counts (over than 4 logs). The colony counts from P-L-, P+L- and P-L+ groups remained constant.
Conclusion:
Within the limitations of this study, it was concluded that curcumin-mediated PDT proved to be effective for in vivo inactivation of C. albicans without harming the host tissue of mice.