Efeitos do transplante autólogo de células monocelulares da medula óssea após lesão incompleta da medula espinhal de ratos adultos

Abstract

Spinal cord injury (SCI) causes permanent loss of neurological function below the level of injury, generating social and psychological physical consequences in patients. The pathophysiology of SCI involves complex processes, such as hemorrhage, excitotoxicity and inflammation, mainly generated by microglial cells. Despite advanced knowledge of pathological mechanisms, effective and approved therapeutic strategies for the treatment of lesions and their consequences are still lacking without serious adverse effects. Cell therapy may represent a good therapeutic strategy because it demonstrates good results in the modulation of the inflammatory environment of the lesion and by probable mechanisms of differentiation. In the present study, we investigated the action of bone marrow mononuclear cells (BMMC) in incomplete lesions (hemisection to the right of the spinal cord, T8-T9 segment) after 42 days of injury (chronic lesion). The cells were from the injured animal itself (autologous transplantation) and the transplantation was intramedullary, i.e. the cells were inserted near the site of the lesion. In the present study, the functional effects of transplantation were investigated through the BBB scale (Basso, Beatie and Bresnahan), which allows the motor function of the hind legs of the animals to be graded. The anti-inflammatory effects of BMMC were also investigated. Histological and immunohistochemical techniques using Cresila Violet staining and anti-ED-1 (microglial marker / activated macrophages) and anti-GFAP (fibrillar astrocyte marker) antibodies were used. Qualitative and quantitative analyzes were performed. For quantitative analysis, the number of field activated astrocytes and macrophages / microglia were counted using binocular microscope with counting gradient (0.0625mm2) in a 40x objective. The counting averages and the standard deviations obtained were plotted in Cartesian coordinates. The counting was as follows: on the right side of the spinal cord (lesion side) and three fields per medullary region (ventral funiculus - FV, dorsal funiculus - FD, lateral funiculus - FL, dorsal horn - CD, ventral horn - CV and intermediate gray matter-SCI), totaling 18 counting fields per section. Treatment with BMMC was not effective in improving the motor function of the injured animals when we compared the treated and untreated animals (means and standard deviations of the groups: false operated, n = 4, 21 ± 0, control, n = 4, 13,57 ± 3.88, treated, n = 5, 15.07 ± 3.46). In the qualitative analysis by means of the staining of Cresila Violet, treated animals presented better tissue preservation when compared to the untreated animals. In the quantitative analysis of microglial activation, we observed that treatment with BMMC reduced the activation of these inflammatory cells (control: 19.52 ± 7.79, treated: 10.04 ± 2.37), but did not significantly reduce the activation of the astrocytes (Mean of the groups: control 17.74 ± 2.757, treated 14.46 ± 5.283). The results suggest that further studies are needed to come up with an effective strategy for patients with SCI. A possible combined treatment with other strategies may turn out to be promising for patients' functionality.