ω-Conotoxina MVIIC e células tronco mesenquimais, isoladas ou associadas no tratamento de ratos submetidos ao trauma medular agudo

Abstract

The objective of this study was to evaluate the effect of ω-conotoxin MVIIC and mesenchymal stem cells (MSCs) isolated and its association in rats submitted to acute spinal cord trauma. Thirty-six Rattus norvegicus, Wistar strain, were used in the study. Six thirty-day-old animals, with an average weight of 120 g, were used for the collection and extraction of bone marrow-derived MSCs, cultivated until the third passage. The remaining animals, three-month-old males with an average weight of 350 g, were randomly distributed in five experimental groups with six animals: negative control (CN), positive control (CP), ω-conotoxin MVIIC (MVIIC), bone marrow mesenchymal stem cells (CTM-MO) and the association (MVIIC + CTM-MO). The CN group underwent T12 vertebra laminectomy without spinal cord trauma, and the other groups were submitted to laminectomy followed by contusive spinal cord trauma. The CP group received 10 μl of PBS and the MVIIC group 10 μl of PBS containing 20 pmol of ω-conotoxin, both intrathecally one hour after spinal cord trauma. The CTM-MO group received intravenously 0,2 ml of PBS, containing 1x106 of CTM, in the lateral tail vein 24 hours after the trauma, and the MVIIC + CTM-MO group received intrathecally 10 μl containing 20 pmol of ω-conotoxin MVIIC, one hour after trauma, and 1x106 of CTM intravenously 24 hours after acute spinal cord trauma. The animals were observed for seven days. The locomotor function of these animals, the generation of reactive oxygen species, lipid peroxidation, and gene expression of apoptosis factors were evaluated. In the treatment with MVIIC + CTM-MO, recovery of the motor function of the animals was observed after acute spinal cord trauma and reduction of Bax gene expression (p<0,05). There was no reduction of oxidative stress and pro-apoptotic factors caspases-3, 8 and 9 in the studied groups (p>0,05). It can be concluded that the association of ω-conotoxin MVIIC with mesenchymal stem cells conferred neuroprotection in acute medullar trauma. The MVIIC acted synergistically, improving its action and reducing apoptosis and, consequently, with recovery of motor function.