Preliminary study of mechanism and neuroprotective effects of hydrogen-rich saline intraperitoneal injection in rats with acute cauda equina symdrome

English Keywords:Cauda equina syndrome  Hydrogen  Oxidative stress  Apoptosis  Rat

English Abstract:

  【Abstract】 Objectives: To study the mechanism and neuroprotective effects of hydrogen-rich saline intraperitoneal injection in rats with acute cauda equina syndrome. Methods: 168 SD rats weighing 200-250g were randomly allocated into three groups: sham-operation group, control group and experimental group. The L5 spinous process and ligamentum flavum between L5 and L6 vertebra was removed in sham-operation group, the rat models of acute cauda equina syndrome were made in control group and experimental group. Hydrogen-rich saline was injected intraperiteonally in a 5ml/kg dose after operation immediately and then once every 8 hours in experimental group; normal saline was injected in sham-operation group and control group. 3h, 6h, 12h, 24h, 48h and 72h after operation, 8 rats from each group were respectively examined by the hot plate test, then their samples of L4-L6 cauda equine, T13-L1 spinal cord and dorsal root ganglia of L5 and L6 were harvested to analyze tissue concentrations of MDA. At 48h, the samples experienced HE, NF, Capases 3 and Tunel staining. By the above methods, animal ethology, oxidative stress, histomorphology and cell apoptosis were evaluated statistically. Results: The paw-withdrawal latency in 3h groups was unavailable due to different recovery time from anesthesia. From 6h to 72h, the paw-withdrawal latency in experimental group was lower than control group, and both control group and experimental group had higher latency than sham-operation group(P＜0.05). The MDA level of cauda equine, spinal cord and dorsal root ganglia in control group and experimental group increased significantly at the time from 3h to 48h(P＜0.05) and showed no significant difference between the 48h and 72h(P＞0.05). The MDA level increased at 3h in control group and at 24h in experimental group(P＜0.05). The experimental group form 3h to 72h had lower MDA level, than control group, while control group or experimental group had higher MDA level than sham-operation groups(P＜0.01). The positive rate of NF staining was 100% in sham-operation group, (59.08±6.25)% in the experimental group, （21.35±2.38）% in the control group, pairwise comparisons among the three groups showed significant differences(P＜0.01). The positive index of Caspases 3 staining of spinal cord and dorsal root ganglia in control group or experimental group was higher than that in sham-operation group(P＜0.01), while experimental group was lower than control group(P＜0.05). Tunel apoptotic index of spinal cord and dorsal root ganglia in control group or experimental group was higher than that in sham-operation group, while experimental group was lower than control group(P＜0.01). Conclusions: In acute cauda equina syndrome, Hydrogen-rich saline may improve ethology performance and reduce neurons apoptosis and degeneration of nerve fibers through restrained and deferred oxidative stress.