Histological Evaluation of Wound Healing Process after Photodynamic Therapy of Rat Oral Mucosal Ulcer

Statement of the Problem: When the body defense is compromised, wounds can act as a route for entrance and colonization of microorganisms in the body. Photodynamic therapy with methylene blue is known as a promising antimicrobial modality. Purpose: The present study aimed to investigate the effects of this procedure on wound healing processes. Materials and Method: In this experimental study, 48 male Wistar rats were recruited. Experimental wounds were surgically made on their buccal mucosa. Based on the treatment modality, they were divided into 3 groups (n=16) of control (CG), laser (LG), photosensitizer+ laser (PLG) by methylene blue (MB). The treatment procedure in the two latter groups was done in days 1-4 and 6-9. After sacrificing on 2, 4, 7 and 14-day follow-ups, the microscopic grade of healing of the wounds was assigned on each interval according to histological grading criteria. Results: A qualitative result was obtained that showed a healing progression in PLG at day 2 of follow-up. At day 4 of follow-up, no difference was seen in healing stage among the groups. However on day 7 of follow-up, samples of the LG showed a lower degree of healing compared with the other two groups. Likewise, on day 14 of follow- up, both PLG and LG showed lower degree of healing than CG. Conclusion: This study qualitatively showed that MB- mediated photodynamic therapy would have an inhibitory effect on healing process after 14 days of the wound creation.