The Mechanism Of JAK-STAT Signal Transduction Pathway In Acute Carbon Monoxide Poisoning Delayed Encephalopathy

Objective: Discuss the mechanism of JAK-STAT signal transduction pathway in acute carbon monoxide poisoning delayed encephalopathy.Method: 80 healthy adult male SD rats were randomly divided into two groups, which were the control group(not exposed) and the CO group, each group was divided into 3d, 7d, 14 d, 21 d, 28 d five subgroups, then used static inhalation method to prepare acute carbon monoxide poisoning delayed encephalopathy model; water maze test was used to detect related indicators, which were the average escape latency in each group, the number of crossing the original platform, the time of first arrival to the original platform, the ratio of the total time and the activity time in the original platform quadrant, to evaluate the spatial learning and memory ability of the rats; HE method was used to observe the hippocampus histopathological changes of the rats in each group; immunohistochemical staining was used to observe the situation of the hippocampus P-JAK2, P-STAT3 immunopositive cells; western blot method was used to detect the expression level of P-JAK2, P-STAT3 in the rats’ brain; Tunel method was used to detect the apoptosis of neuronal cells in the rats’ hippocampal tissue.Results:(1) water maze test: 3d and 7d in the control group and after exposed, the comparisons of the average escape latency in each group, the number of crossing the original platform, the time of first arrival to the original platform, the ratio of the total time and the activity time in the original platform quadrant, all had no significant difference(P>0.05); after exposed, compared the time points in 14 d, 21 d and 28 d with the control group, the average escape latency in the CO group was significantly longer, the number of crossing the original platform was significantly reduced, the time of first arrival to the original platform was extended, the ratio of the total time and the activity time in the original platform quadrant was obviously decreased, which all had statistically significant(P<0.05), and showed that the spatial learning and memory ability of the rats were impaired. The trajectory of the rats in the control group tended to be linear motion, and the trajectory of the rats in the exposed group at the time point of 14 d presented to be irregular and similar to circular motion.(2) The results of HE staining: results of HE staining: in the control group, the hippocampus histopathology at each time point was normal; it could be seen in the CO group that the neuronal cells were significantly swelling, the cell layers were sparse, and neuronal cell necrosis could be seen; few nucleus were ruptured and had stained phenomenon; as the exposed time extended, neuronal cell necrosis and apoptosis gradually increased, the number of neuronal cells gradually decreased, the cells were arranged disorderly.(3) The results of immunohistochemistry: in the rats’ brain tissue of the control group, there was no expression of P-JAK2, P-STAT3 protein, in the brain tissue of the CO group, after exposed at 3d, P-JAK2, P-STAT3 positive cells could be seen, and at 7d the expression level reached to the peak; as the exposed time extended, the expression level of P-JAK2, P-STAT3 protein gradually decreased, but there still expression at 28 d after exposed.(4) The results of western blot: in the control group, P-JAK2, P-STAT3 almost had no expression in the rats’ brain tissue; after exposed, the expression level of P-JAK2, P-STAT3 in the CO group significantly increased, and at 7d it reached to the peak, thereafter it gradually decreased as the exposed time extended, but there still expression in the brain tissue at 28 d after exposed.(5) The detection results of Tunel cell apoptosis: in the rats’ hippocampus tissue of the control group, Tunel positive cells could be occasionally seen; after exposed at 3d, the cell apoptosis index in the rats’ hippocampus tissue significantly increased, compared with the control group, it was statistically significant(P<0.05), and at 7d the cell apoptosis reached to the peak, as the exposed time extended, the cell apoptosis index gradually decreased. Conclusion:(1) Using static inhalation method to prepare the DEACMP rat model, is similar to the actual clinical poisoning process, its brain pathology and behavioral changes are consistent with the clinical, at the same time, the method is simple and has high safety factor, it can be the preferred method to prepare DEACMP rat model.(2) Morris water maze test can detect the spatial learning and memory ability of the rats after acute CO poisoning, and can be the standard that if the DEACMP model is successfully prepared.(3) After CO poisoning, JAK-STAT signal transduction pathway can be activated.(4) JAK-STAT signal transduction pathway may be associated with the neuronal cell apoptosis after acute CO poisoning.(5) The excessive activation of JAK-STAT signal transduction pathway is involved in the occurrence and development of DEACMP, and provides new therapeutic targets to the prevention and treatment of DEACMP.