Comparison of three different dosages of low-level laser therapy on expression of cell proliferation and inflammatory markers following ovariohysterectomy in rats.

The objective of the current study was to evaluate Low-level laser therapy (LLLT) on the healing of incisional wounds following ovariohysterectomy in rats, by means of subjective histopathological and immunohistochemical analysis. A total of 72 female Wistar rats were categorized into four treatment groups (Group I; sacrification 4 hours following only one LLLT application, Group II; sacrification 7 days following only one LLLT application, Group III; sacrification 4 hours after two LLLT applications, and Group IV; sacrification 7 days after two LLLT applications). Each group was further divided into four different doses subgroups (Group Control [C, off mode LLLT application], L 1 [1 J/cm 2 ], L 3 [3 J/cm 2 ], and L 6 [6 J/cm 2 ]), with equal representation in each subgroup. Ovariohysterectomy was employed using two 2-cm-length midline abdominal incisions in the left and right sides of line alba. The Group C was assigned to the left side incision to each rat in the study. After irradiation, the tissue was subjected to histopathological analysis to determine the extent of mononuclear cell infiltration, edema, and epithelialization. Additionally, immunohistochemical analysis was performed to evaluate the expression of proliferating cell nuclear antigen (pCNA) and inducible nitric oxide synthase (iNOS). Group L 1 and L 3 significantly decreased mononuclear cell infiltration compared with Group C in all treatment groups ( p  < 0.05). Group L 3 significantly decreased edema compared with Group C in all groups except for treatment Group I ( p  < 0.05). Group L 2 and L 3 significantly increased epithelization in treatment Group IV ( p  < 0.05). Moreover, Group L 2 and L 3 significantly increased pCNA in all groups, while L 2 and L 3 significantly decreased iNOS expression in treatment Group II, III, and IV ( p  < 0.05). However, no statistical difference was found between subgroups of treatment Group I in iNOS expiration ( p  > 0.05). The results of the current examination demonstrated that LLLT can modulate mononuclear cell infiltration and edema, and improve epithelization, as well as increase pCNA expression, whereas decrease iNOS expression during the wound healing process, therefore enhancing wound healing following ovariohysterectomy in rats.