[Effects of emodin on oxidative stress and inflammatory response in rats with acute spinal cord injury]

Abstract

This paper was aimed to investigate the effects of emodin on oxidative stress and inflammatory response in rats with acute spinal cord injury（SCI）, and to explore the protective mechanism of emodin on neurons after SCI. Rat SCI models were established using a modified Allen's method. One hundred and ninety five Sprague-Dawley rats were randomly divded into sham (group A), model (group B), emodin group of 20 mg·kg⁻¹(group C), emodin group of 40 mg·kg⁻¹(group D), emodin group of 80 mg·kg⁻¹(group E). Functional recovery was evaluated using the Basso-Beattie-Bresnahan (BBB) scale and inclined plate test on the 3rd, 7th, 14th and 28th day. On the 7th day after SCI, neuron nylon body was observed with toluidine blue staining. The changes of myelinated nerve fibers were observed by transmission electron microscope. Nrf2, HO-1, NQO1, GFAP, NF-κB protein were detected by Western blot. The content of TNF-α, IL-1β, IL-6 were detected by ELISA. Immunofluorescence staining was performed to observe the expression of the GFAP, NG2 and ED-1. The BBB and inclined plate scores of group C, D and E were higher than group B on the 7th, 14th, 28th day,the difference was statistically significant (P<0.05). On the 7th day, Nylon Body of group B and C started to fuse,the fusion of group D and E were significantly alleviated than group B and C. Transmission electron microscope showed that the changes of demyelination were obvious in group B and C, group D and E were significantly improved than group B and C. Western blot showed that Nrf2, HO-1, GFAP, NF-κB protein expression,group C, D, E compared with group B, NQO1 protein expression, group D, E compared with group B, the difference was statistically significant (P<0.05). ELISA showed that the content of TNF-α, IL-6,group C, D, E compared with group B,the content of IL-1β,group D, E compared with group B, the difference was statistically significant (P<0.05)；Immunofluorescence showed that the expressions of GFAP and NG2 in group C, D and E were higher than that in group B, and the group D and E were more obvious. The expression of ED-1 in group C, D, E were decreased significantly compared with group B. Emodin has protective effect on neurons after SCI. The mechanism may connect with activting Nrf2-ARE pathway, reducing the expression of NF-κB, ED-1, TNF-α, IL-1β, IL-6, and promoting the expression of GFAP and NG2.

Keywords: emodin; glial fibrillary acid protein; inflammation; neuronglialantigen-2; oxidative stress; spinal cord injury.