Aspectos morfológicos do músculo esquelético durante o processo de reparo após inoculação de células C2C12 e irradiação com laser de baixa potência

Abstract

Satellite cells (SC) are present in adult muscle tissue and are activated after a injury. The low-level laser therapy (LLLT) has shown step in positively during muscle repair process by modulating different phases, but little is known about its effects when combined with cell inoculation. Therefore, the objective of the study was to analyze the effect of LLLT after inoculation of muscle satellite cells of C2C12 on the repair process of skeletal muscle of rat after cryoinjury. Wistar rats were randomly divided into 4 groups: (1) control, (2) injury, (3) Injury + C2C12 (4) Injury + C2C12 + LLLT. The cryoinjury was carried out by two applications with a cold bat in liquid nitrogen directly into the tibialis anterior muscle (TA). Inoculation of C2C12 muscle cells was performed immediately after cryoinjury utilizing 1x106 cells directly into the lesion site with a 30 needle with a depth of 2 mm sized through limiters. After two hours of inoculation LLLT (GaAlAs, 780 nm, 10 J / cm2, 40 mW, J 3.2, 10 seconds per point being 8 irradiation points) was applied daily, and the analysis periods was 1, 3 and 7 days. The morphological aspects were analyzed qualitatively and quantitatively by HE staining. Subsequently, the qualitative and quantitative analysis of collagen fibers by Picrosirius and marking of CD68 + by immunohistochemistry was performed. Data were expressed as mean and standard error of the mean (ANOVA / Tukey). The results showed that after one day, three and seven days there was an increase in collagen deposition of the group injury + C2C12 + LLLT compared to injury group and injury + C2C12 group. Moreover, after seven days there was an increase in the number of blood vessels in the lesion + C2C12 group compared to injury and injury + C2C12 + LLLT grous. In the same period, there was a decrease in the number of immature muscle fibers in injury + C2C12 + LLLT group when compared to the groups injury and injury + C2C12. There was no significant difference in the number of inflammatory cells, myonecrosis and marking of CD68 in all the groups in the three periods of analysis. Therefore, the findings show that inoculation of C2C12 satellite cells of mice modulated some aspects of the inflammatory process including increased mature vessels and had no effect on the inflammatory infiltrate, myonecrosis and immature muscle fibers. And when he made the association with LLLT, there was only an increase in collagen deposition in 7 days and there was no modulation of the other aspects evaluated.