Tauroursodeoxycholic acid protects rat spinal cord neurons after mechanical injury through regulating neuronal autophagy.

BACKGROUND:To study the protective effect of tauroursodeoxycholic acid (TUDCA) on the spinal cord nerve cells (SCN) of SD rats and to explore the protective mechanism of TUDCA against mechanical injury of the SCN. MATERIAL AND METHODS:The SCN of SD rats were cultured in vitro, and a mechanical injury models of 1 mm, 3 mm, and 5 mm SCN were established. The cell survival rate was determined using the MTT assay to determine the optimal degree and time of injury. Different concentrations (0.5, to 20 mmol/L) of TUDCA were used to detect SCN cell survival rate after mechanical injury. MTT assay was used to determine the optimal TUDCA intervention dose. SCN autophagy in different experimental groups were observed by electron microscopy after the best degree of mechanical injury, time of injury, and TUDCA concentration. Beclin-1 and LC3 II/I expressions were detected by western blotting and immunohistochemistry. RESULTS:Survival rate of SCN was close to 50% when the injury interval was 3 mm and the injury time was 24 h, significantly different from those of each group (P < 0.05). At 3 mm injury interval and 24 h injury time, SCN survival rate was approximately 80% when TUDCA concentration was 4 mmol/L, which was significantly different from those of each group (P < 0.05). Cell morphology of the normal control group was complete, with few autophagy lysosomes. Compared with the normal control group, the number of autophagic lysosomes in the mechanical injury group increased, and cell damage was more severe. Compared with the mechanical injury group, the number of autophagy lysosomes in the mechanical injury + TUDCA intervention group increased significantly, and cell damage was less severe. Further, compared with the normal control group, beclin-1 and lc3ii / I expressions in the mechanical injury group were significantly higher (P < 0.05); compared with the mechanical injury group, beclin-1 and lc3ii / I expressions in the mechanical injury + TUDCA intervention group were significantly higher (P < 0.05). CONCLUSION:TUDCA can protect SCN from mechanical injury in vitro, which may be related to the enhancement of the expression of autophagy-related protein beclin-1 and LC3 II/I.