The effect of edaravone on cognition function and expression of Nogo-A in rats with serious intermittent hypoxia / 中国中西医结合急救杂志

ABSTRACT

Objective To observe the effect of edaravone (ED) on cognition function and expression of Nogo-A in prefrontal cortex neuron of rats with serious intermittent hypoxia.Methods Ninety-six adult male Wistar rats were randomly divided into normal control group, chronic intermittent hypoxia (CIH) model group and ED group, 32 rats in each group. The rat model of CIH was reproduced in a low oxygen box at 0800-1500 every day alternatively, different flow rates of nitrogen and compressed air were given, 120 seconds being one cycle, maintaining the oxygen concentration at 5%-21% in the low oxygen chamber; the normalcontrol group was continuously under the circumstance fulfilled with compressed air. The rat in ED group was given intravenous injection of 3 mg/kg ED in a tail vein at 0700 daily. After modeling for 7, 14, 21, 28 days, the learning and memory functions of rats were assessed with the Morris water maze test, and the reactive oxygen species (ROS) content in the rat prefrontal lobe tissue was detected; the level of Nogo-A protein expression in the rat prefrontal cortex was examined by immunohistochemical method .Results ① Rat learning results: in CIH model group, with the time prolongation escaping latency period was gradually longer, since 14 days after the modeling, the difference was statistically significant compared with that in normal control group, while the learning time in ED group was obviously shorter than that in the CIH model group (seconds 14 days was 26.97±3.35 vs. 34.95±3.36, 21 days was 32.78±4.59 vs. 46.72±4.11, 28 days was 41.39±3.84 vs. 57.35±3.72, allP < 0.05). ② Rat memory results: the rats in CIH model group, with the time prolongation crossing the target quadrant time was gradually shorter, since 14 days after the modeling, the difference was statistically significant compared with that of the normal control group, while the memory time in the ED group was obviously longer than that of the model group (seconds 14 days was 42.72±3.35 vs. 39.88±3.56, 21 days was 40.48±4.62 vs. 28.72±3.93, 28 days was 31.13±3.46 vs. 22.79±3.24, allP < 0.05). ③ ROS content with the time prolongation, ROS content was gradually increased in CIH model group, but the ROS content in ED group was significantly lower than that in CIH model group at various time points (MU/L 7 days was 13.27±0.23 vs. 17.68±0.51, 14 days was 15.51±0.28 vs. 20.41±0.65, 21 days was 20.29±0.44 vs. 23.86±0.35, 28 days was 24.46±0.53 vs. 30.43±0.85, allP < 0.05). ④ Protein expression of Nogo-A with the time prolongation, the protein expression of Nogo-A was gradually increased in CIH model group, they reached the peak on the 14th day, the expression of Nogo-A [absorbance (A) value] in ED group were significantly lower than that in CIH model group at each time point (×103 7 days was 4.80±0.70 vs. 5.99±0.62, 14 days was 5.89±0.90 vs. 7.42±0.66, 21 days was 4.92±0.64 vs. 5.90±0.37, 28 days was 3.59±0.59 vs. 4.27±0.40, allP < 0.05).Conclusions The mechanism of ED has a valid therapeutic effect on the cognitive dysfunction induced by serious intermittent hypoxia in rats, ED can remove oxygen free radicals and inhibit the protein expression of Nogo-A in the prefrontal cortex, so ED can alleviate the damage of cognitive function in rats with CIH.