Assessment of the effect of diode laser therapy on incisional wound healing and expression of iNOS and eNOS on rat oral tissue

Background: The aim of this study was to compare the effects of diode laser irradiation on wound healing in oral rat mucosa and also to measure the amount of inducible nitric oxide synthase (iNOS) and endothelial NOS (eNOS) on oral wound healing. Healing was assessed by histology and the amounts of eNOS and iNOS were measured by real‑time polymerase chain reaction (PCR). Materials and Methods: Twenty‑four standardized incisions were carried out on the buccal mucosa of 12 male Wistar rats; each rat received two incisions on the opposite sides of the buccal mucosa by using a steel scalpel. On the right side (test side), a diode laser (660 nm) was employed on the incision for 10 seconds on days 1‑4 and 6‑9. The left side (control side) did not receive any laser. Histological and real‑time PCR analysis were done on tissue samples after 2, 7, 14, and 21 days. Results: Histological analysis showed that the tissue healing after seven days on the laser irradiated side was better than the control side, but there was no significant difference between the two sides on days 2, 14, and 21 after surgery. Paired t-test analysis showed that there was no significant difference in the amount of eNOS between the groups. The difference in the amounts of iNOS between the groups was significant; it was more in the laser‑irradiated side than the control side. Conclusion: Histological findings showed that diode laser needs several repeated irradiations for the acceleration of wound healing. The iNOS amount showed that increases are associated with better healing.