Iranian Veterinary Surgery Association (IVSA) Iranian Journal of Veterinary Surgery 2008-3033 20 2 2025 10 01 Functional Recovery in Spinal Cord-Injured Rats Treated with Melatonin-Chitosan Hydrogel: A Behavioral Study 151 158 224772 10.30500/ivsa.2025.521768.1445 EN Fariborz Afroozi Department of Veterinary Clinical Sciences, SR.C., Islamic Azad University, Tehran, Iran. Ahmad Asghari Department of Veterinary Clinical Sciences, SR.C., Islamic Azad University, Tehran, Iran. Gholamreza Abedi Department of Veterinary Clinical Sciences, SR.C., Islamic Azad University, Tehran, Iran. Pejman Mortazavi Department of Pathobiology, SR.C., Islamic Azad University, Tehran, Iran. Hesam Uddin Hoseinzadeh Department of Clinical Sciences, Karaj Branch, Islamic Azad University, Karaj, Iran. Journal Article 2025 05 06 Spinal cord injury (SCI) leads to the loss of neural and glial cells, along with significant neuroinflammation. Hydrogel formulation, designed for sustained melatonin release, has shown promising therapeutic potentials. In this study, SCI was induced in rats via T9 vertebral contusion, and the CH/Mel hydrogel was characterized using SEM and FTIR. SEM imaging confirmed the hydrogel porous structure. Twenty male Wistar rats were divided into five groups (n = 4 per group): SHAM group with no surgery. SCI group: SCI-induced rats were treated locally with 100 µl CH hydrogel as a control group. SCI/50 group: SCI-induced rats were treated locally with 100 µl CH hydrogel containing 50 mg/kg melatonin. SCI/100 group: SCI-induced rats were treated locally with 100 µl CH hydrogel containing 100 mg/kg melatonin. SCI/200 group: SCI-induced rats were treated locally with 100 µl CH hydrogel containing 200 mg/kg melatonin. <em>In vitro</em> tests revealed that 25 mg/ml CH/Mel hydrogel significantly boosted U87 cell viability after 24 hours. Behavioral assessments demonstrated that CH/Mel hydrogel treatment markedly improved functional recovery in SCI rats, supporting its therapeutic efficacy. The use of CH/Mel hydrogel was shown to effectively enhance the recovery of rats with SCI indicated by improving behavioral assessments. https://www.ivsajournals.com/article_224772_b1fec3905cc79996b9f45423f5adfb37.pdf