Preparation and evaluation of controlled released implant containing mesoporous selenium nanoparticles loaded with curcumin in rats with spinal cord injury.

In this study, a controlled released delivery drug system designed and synthesized by loading curcumin and selenium nanoparticles (SeNaPs) on chitosan hydrogel, and while evaluating the physicochemical properties of the prepared drug delivery system, the tissue changes caused by the local implant of that system in rats with experimental spinal cord injury (SCI) were investigated. For this purpose, 100 adult female rats were randomly divided into five equal groups which are: Control group without any treatment for SCI, chitosan group that received chitosan hydrogel, curcumin group that received curcumin-loaded hydrogel, SeNaP group that received chitosan loaded with SeNaPs and SeNPCur group that received chitosan loaded with SeNaPs and curcumin. On the 3^rd and 7^th days of the study, severe infiltration of leukocytes, especially lymphocytes, as well as axon swelling and hemorrhagic necrosis at the lesion sites were observed in all groups, especially the control group. On the 7^th day, the severity of these injuries decreased in the SeNPCur group and the highest number of astrocytes was observed in this group. In addition, on the 14^th and 21^st days of the study, the lowest severity of nerve tissue damage and the lowest presence of inflammatory cells along with the highest number of astrocytes were seen in the SeNPCur group. The glial fibrillary acidic protein study also confirmed the presence of more and significant astrocytes in the SeNPCur, curcumin and SeNP groups at different times of the study, respectively. The histopathological results showed the neuroprotective effects of chitosan hydrogel loaded with selenium and curcumin.