Effects of gangliosides on expressions of caspase-3 and NGF in rats with acute spinal cord injury

摘要

OBJECTIVE: To investigate the effects of ganglioside [monostalotetra-hexosylganglioside (GM1)] on the expressions of caspase-3 and nerve growth factor (NGF) in rats with acute spinal cord injury (SCI). MATERIALS AND METHODS: Male Sprague- Dawley (SD) rats were selected and randomly divided into Sham group, SCI group and GM1 administration group. The rats in Sham group, SCI group and GM1 group were subjected to behavioral examinations of Basso Beattie Bresnahan (BBB) and oblique-plate test at 1, 7 and 14 d after operation. The content of methylene dioxyamphetamine (MDA) and the activity of superoxide dismutase (SOD) of every rat in each group were measured by enzyme-linked immunosorbent assay (ELISA). Immunofluorescence staining assay was used to detect the expression levels of caspase-3 and NGF of rats in each group. The messenger ribonucleic acid (mRNA) and protein expressions of caspase-3 and NGF of rats in Sham group, SCI group and GM1 group were detected using reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blotting assay. RESULTS: The BBB scores and the results of oblique-plate test in Sham group, SCI group and GM1 group at 1, 7 and 14 d showed that the BBB scores and the results of oblique-plate test of rats in each group were significantly decreased at 1 d after SCI, and had different degrees of recovery at 7 and 14 d after injury. The results of ELISA detection revealed that SCI group had increased content of MDA and clearly decreased activity of SOD in comparison with Sham group; at the same time, MDA content in GM1 group was overtly lower than that in SCI group, while SOD activity was enhanced evidently in GM1 group compared with that in SCI group. According to immunofluorescence assay, significantly increased expression of caspase-3 and distinctly decreased expression of NGF were found in SCI group. However, this phenomenon was significantly reversed by GM1. RT-PCR and Western blotting assay severally proved that the mRNA and protein expressions of caspase-3 were raised in SCI group and decreased clearly after the administration of GM1; while the mRNA and protein expressions of NGF was significantly reduced in SCI group and overtly elevated after the administration of GM1. ANOVA showed that there were statistically significant differences in expressions of caspase-3 and NGF among Sham group, SCI group and GM1 group (p<0.05). CONCLUSIONS: GM1 has an evident effect on the expressions of caspase-3 and NGF in rats with acute SCI, and is able to down-regulate the expression of caspase-3 and up-regulate the expression of NGF, so as to achieve its therapeutic effect on SCI.