Therapeutic effectiveness of conditioned medium derived from adipose tissue mesenchymal stem cells and dehydroepiandrosterone in a rat model of spinal cord injury.

Background and objective: Spinal cord injury (SCI) is a severe neurological disorder that leads to significant complications, including loss of bladder/bowel control and increased infection risk. The current standard treatment involves methylprednisolone administration and surgical decompression, but finding an effective therapy with minimal side effects remains a major challenge. This study aimed to investigate the effects of an optimized conditioned medium derived from rat adipose-derived mesenchymal stem cells (AD-MSCs) and dihydroepiandrosterone (DHEA) on behavioral indices, oxidative stress, stereological parameters, and histopathological outcomes in rats with compressive spinal cord injury (SCI). Material and methods: In this study, 60 adult female rats were randomly divided into five groups: Sham group (laminectomy + intraperitoneal injection of 1 % dimethyl sulfoxide [DMSO], 200 µL for seven consecutive days), SCI-induced group (SCI induction + intraperitoneal injection of 1 % DMSO, 200 µL for seven consecutive days), Treatment group 1 (SCI induction + intraperitoneal injection of DHEA [30 mg/kg] dissolved in 1 % DMSO for seven consecutive days), Treatment group 2 (SCI induction + intraperitoneal injection of conditioned medium [200 µL] for seven consecutive days), Treatment group 3 (SCI induction + intraperitoneal injection of DHEA [30 mg/kg] dissolved in 1 % DMSO followed by conditioned medium [200 µL] for seven consecutive days). Behavioral assessments were performed using the Basso, Beattie, and Bresnahan (BBB) locomotor rating scale and the rotarod test. Additionally, the levels of antioxidant enzymes-catalase, glutathione (GSH), superoxide dismutase (SOD), and the lipid peroxidation marker malondialdehyde (MDA)-were measured using respective assay kits. For stereological evaluation (to estimate neuronal and non-neuronal cell counts, gray and white matter volumes, spinal cord volume, and lesion area) and histopathological assessment (to evaluate inflammation, necrosis, and hemorrhage indices), tissue samples were stained with Cresyl Violet. Results: The findings revealed that in the SCI-induced group, motor function, neuronal cell number in spinal gray matter, non-neuronal cell number in the spinal cord, white and gray matter volumes, total spinal cord volume, and levels of catalase, GSH, and SOD were significantly reduced compared to the sham group. Conversely, the spinal lesion volume and MDA levels were elevated. Treatment with DHEA, AD-MSC-conditioned medium, or their combination reversed these effects. Notably, the combined treatment group exhibited more pronounced therapeutic improvements compared to monotherapy groups. Conclusion: The administration of DHEA and AD-MSC-conditioned medium, particularly in combination, appears to enhance motor function, elevate antioxidant enzyme activity, reduce lipid peroxidation, improve spinal cord structural parameters (volume and cell counts), and ameliorate pathological markers in an animal model of compressive SCI.