Comparison of the Effects of Perineural and Intraperitoneal Ozone Therapy on Nerve Healing in an Experimental Sciatic Nerve Injury Model

<i>Background and Objectives:</i> The aim was to evaluate nerve healing using immunohistochemical, histological, and functional techniques and to compare the effects of two different therapeutic ozone application methods by perineural and intraperitoneal ozone treatment in rats with a crush injury model of sciatic nerve. <i>Materials and Methods:</i> Forty male Sprague Dawley rats were divided into four subgroups of ten rats each: (1) Control group: The left sciatic nerve incised and closed without crush injury, no treatment; (2) Paralyzed group: Crush injury to the left sciatic nerve, no treatment; (3) Perineural ozone group: Crush injury to the left sciatic nerve, treated with perineural ozone therapy; (4) Intraperitoneal ozone group: Crush injury to the left sciatic nerve, treated with intraperitoneal ozone therapy. The treatments were administered for a 14-day period. Hematoxylin and eosin (H&E) and toluidine blue staining were used for histological examination; TUNEL staining was used for immunohistochemical examination. Pinch test and rotarod performance assessment were utilized for functional evaluation. <i>Results:</i> The pinch test scores showed significant improvement in perineural and intraperitoneal ozone treatment groups after treatment (<i>p</i> < 0.001 and <i>p</i> = 0.003, respectively). The scores of myelin degeneration, vascular congestion, vascular wall thickness, inflammation, and toluidine blue and TUNEL staining were significantly lower in both ozone treatment groups compared to the paralyzed group (<i>p</i> < 0.001). Vascular wall thickness scores were significantly higher in the perineural ozone group compared to the control and intraperitoneal ozone groups (<i>p</i> = 0.004 and <i>p</i> = 0.013, respectively). The Schwann cell proliferation scores were significantly higher in the perineural ozone group compared to the control group and intraperitoneal ozone groups (<i>p</i> < 0.001). <i>Conclusions:</i> Both applications of ozone therapy accelerated the healing of nerve regeneration, reduced inflammation and apoptosis based on histopathological results, and enhanced nerve function in rats with sciatic nerve injury. Perineural ozone therapy has been demonstrated to be an efficacious alternative to systemic ozone treatments in the management of sciatic nerve injury. Further studies are needed to determine optimal ozone dosage and administration protocols for the treatment of nerve injury.