Study On The Molecular Mechanism Of Methimazole's Immunosuppressive Effect

Objective 1. To investigate the effect of methimazole treatment om reactive oxygen species(ROS) level in thyrocytes and to estabished its structure-effect relationship. 2. To study the effect of methimazole treatment on FasL expression in thyrocytes and to establish its structure-effect relationship. 3. To identify the role of ROS in methimazole-induced FasL expression in thyrocytes and gain a preliminary insight into the methimazole's immunosupressive effect.Methods 1. A primary thyrocyte culture was established. The level of extracellular and intercellular ROS was determined by HVA fluorescent technology and flow cytometry, respectively. The effect of methimazole treatment on ROS level in thyrocytes was studied. 2. The Mouse FasL monoclonal antibody was adopted as primary antibody, and FasL expression in thyrocytes was determined by flow cytometry. The effect of methimazole and ROS on FasL expression in thyrocytes was observed. 3. A co-culture system of thyrocytes and T cell line Jurkat cells was used to evaluate the ability of methimazole-treated thyrocytes to kill target lymphocytes in a FasL-dependent manner.Results 1. Methimazole is capable of scavenging ROS in thyrocytes in a dose-dependent manner. Thiourea shows similiar effect to that of methimazole, but not for imaidzole. DEM can partly inhibit the effect of methimazole. 2. Methimazole upregulate the expression of FasL in thyrocytes in a dose, time-dependent manner, while ROS generating system X/XO can reverse the effect of methimazole. Thiourea shows similiar effect to that of mathimazole, but not for imaidizole. DEM can partly reverse the effectof methimazole. 3. Methimazole-treated thyrocytes can kill Jurkat cells in a FasL-dependent manner.Conclusion 1. Mehtimazole can scavenge ROS in thyrocytes, and its effect is associated with thiol radical in its molecular which can change the ratio of intercellular GSH/GSSG. 2. Methimazole can induce FasL expression in thyrocytes. Methimazole-induced FasL present the function as a effector to kill target T lymphocytes which express Fas. The properity of methimazole to scavenge ROS in thyrocytes may be upstream mechanism of its effect to induce FasL expression. And it may be the molecular mechanism of Methimazole's immunosuppressive effect that methimazole induces T lymphocytes apoptosis by FasL-Fas interaction.