AIM: To investigate the effects of melatonin and octreotide in the prevention of peridural fibrosis in an experimental rat model.

MATERIAL and METHODS: A total of 36 rats were divided into three groups: Group I was laminectomized and not given any treatment. Group II received an intraperitoneal 30 μg/kg/day dose of octreotide for six weeks after the laminectomy. Group III rats were injected with melatonin 7.5 mg/kg/day for six weeks after the laminectomy. At the end of six weeks, plasma transforming growth factor beta-1 levels and peridural fibrous tissue hydroxyproline concentrations were determined and histopathological examinations was performed.

RESULTS: Serum TGF-ß1 levels of the octreotide and melatonin groups were found to be lower than the control group. The lower levels of TGF-ß1 was statistically significant in both of the groups. Hydroxyproline levels of the octreotide and melatonin groups were found to be lower than that of the control group. The decrease was statistically significant only in the melatonin group. Peridural fibrosis scores of the octreotide and melatonin groups were lower than the control group. This histopathological improvement was statistically significant only in the melatonin group.

CONCLUSION: Melatonin and octreotide prevented TGF-ß1 increase in peridural fibrosis, but only melatonin significantly improved hyroxyproline levels and fibrosis scores as demonstrated.