| Background and ObjectiveMyasthenia gravis(myasthenia gravis,MG)is an autoimmune disease mediated by acetylcholine receptor antibody and involving acetylcholine receptor in postsynaptic membrane of neuromuscular junction.About 80% of MG patients were accompanied by thymic abnormalities,of which 20-25% were complicated with thymic tumors.Foreign researchers have found that non-neuronal cholinergic system(nonneuronal cholinergic system,NNCS)exists in epithelial cells,lymphocytes,endothelial cells,mesothelial cells,thymocytes and so on.The system is mainly composed of acetylcholine transferase,acetylcholinesterase,nicotinic acetylcholine receptor(nAChR: ? 1-? 10,? 1-? 4,?),muscarinic acetylcholine receptor(mAChR:m1-m5),acetylcholine(ACh)and so on.Participate in the pathogenesis of tumor,dilated cardiomyopathy,primary biliary cirrhosis,scleroderma,anti-inflammatory and antiaging and other diseases.The results of our previous study showed that ? 1,? 2,? 9,? 2 nAChR were expressed in MG patients and normal thymus tissues,mainly in the cytoplasm and membrane of thymocytes,but also a small amount in the nucleus.The expression of ? 1 nAChR in thymus tissue of MG patients was significantly increased,while the expression of ? 2 and ? 2 nAChR was significantly decreased.However,the relationship between the expression of nAChR and the pathological classification of thymus tissue in MG patients is not clear.Therefore,a comprehensive understanding of the expression of nAChR in thymus of different pathological types of MG patients is of great significance for further exploring the pathogenesis of nAChR in MG patients.Materials and Methods1 MaterialsFrom August 2012 to August 2018,126 cases of MG thymus paraffin specimens were collected from The Second Affiliated Hospital of Zhengzhou University.Histological classification of thymus: 23 cases of MG with thymic hyperplasia,65 cases of MG with thymoma(6 cases of type A,16 cases of type AB,10 cases of type B1,17 cases of type B2,16 cases of type B3),38 cases of MG with thymic atrophy.There were 15 cases of normal thymus in the control group.2 Methods1.Immunohistochemical detection of ? 1,? 2,? 9,? 2 nAChR: the expression of ? 1,? 2,? 9,? 2 nAChR was detected by immunohistochemistry,and according to the comprehensive score of cytoplasmic immunohistochemical staining rate and staining degree,the expression of ?1,?2,? 9,?2 nAChR was detected by immunohistochemistry.3 Statistic AnalysisStatistical analysis was performed on the data using SPSS 25.0 software.The ?1,?2,?9,and ?2nAChR were compared with the experimental group and the control group,and the t-test was used to conform to the normal distribution,and the rank sum test was not consistent with the normal distribution.The test level is a=0.05.Results?1,? 2,? 9 and ? 2nAChR were expressed in the thymus of different pathological types of MG patients and the control group,mainly in the cytoplasm and membrane of thymocytes,and a small amount in the nucleus.Compared with normal thymus,?1nachr expression was significantly elevated in thymic hyperplasia group,the expression of ?2 nAChR was significantly decreased in type B2 thymoma,and the expression of ?2 nAChR was significantly decreased in type B3 thymoma(P < 0.05).There was no significant difference in ? 9 nAChR between MG thymus and normal thymus(P > 0.05).ConclusionsThe abnormal expression of ?1,?2 and ?2 nAChR may be involved in the pathogenesis of MG,and thymus is the central immune organ,and the expression of nAChR in thymus of different pathological types of MG patients is different.The abnormal expression of ? 1,? 2 and ? 2 nAChR may be involved in the pathogenesis of MG.This differential expression may be the change of NNCS during the development of thymic T cells,which further confirms that thymus plays a key role in the pathogenesis of MG.Therefore,this study also provides a new target for scientific research and clinical treatment of MG in the future. |
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