The dynamic changes of regulatory T cells in the pathogenesis of experimental autoimmune uveitis / 中华实验眼科杂志

Background Studies show that regulatory T cells (Treg) are a kind of T cell subsets to negatively regulate immune response,and play an important role in maintaining immune homeostasis and immune tolerance.Autoimmune uveitis is an autoimmune disease,the regulation of Treg cells in pathogenesis and progression of autoimmune uveitis is not fully unelucidated.Objective This study was to observe the dynamic changes of Treg in experimental autoimmune uveitis (EAU) rats and explore the role of Treg cells in the pathological process of EAUrats.Methods Eighty four 6-8 week-old SPF Lewis rats were randomly divided into model group and control group.The mixed emulsifier of interphotoreceptor retinoid-binding protein (IRBP)1177-1191,tuberculin (TB),complete Freund adjuvant (CFA) and PBS (300 μl) was subcutaneously injected in double rear foot pad,abdominal side and back,and only equal amount of TB,CFA and PBS emulsifier was used in the same way in the control group.Ocular inflammation symptoms was examined at 9,13,18,23,28,35 and 48 days after modeling and scored based on the severity of the inflammatory.Six rats of each group were sacrificed in above time points respectively for the histopathological examination of iris,ciliary body and retinas by haematoxylin-eosin staining.The lymphocytes were isolated and cultured from rat spleens,and the proportion of Foxp3-labelled cells,a specific marker of Treg cells,was assayed by flow cytometry.The relative expression level of Foxp3 mRNA in the lymphocytes detected by using realtime quantitative PCR (RT-PCR).The use and care of the rats complied with the ARVO Statement.Results Eye inflammatory response appeared at 8 days after immunization,showing vasodilation and hyperemia of rat iris in the model group,and the response peaked at 13 days,with exudation and hypopyon in the anterior chamber.The highest inflammatory scores were 3.75±0.42 at day 13,and the ocular inflammation reaction was gradually relieved after that and disappeared at 23 days after immunity.A significant difference in ocular inflammatory scores of model rats was found among different time points (F =81.709,P ＜ 0.001);while no inflammatory symptom was observed in the control group.Histopathology examination showed obvious infiltration of inflammatory cells in the iris,ciliary body and retinas in model rats,including neutrophils,lymphocytes and mononuclear cells.The proportion of Foxp3-labelled cells in spleen lymphocytes was (5.50 ± 0.64)％,(13.36 ± 0.98)％,(10.34 ± 0.79)％,(9.58 ± 1.02)％,(6.73 ±0.81)％ and (5.58 ± 0.47) ％ in the model group on day 13,18,23,28,35,48 respectively,with statistically significant differences in comparison with (2.80 ± 0.38) ％,(3.36 ± 0.53) ％,(3.65 ± 0.57) ％,(3.37 ± 0.43) ％,(3.33±0.50)％ and (3.13±0.61)％ in the control group (t=-6.272,-15.556,-11.910,-9.753,-6.154,-5.491,all at P＜0.01).The change trend of Foxp3 mRNA expression was consistent to the dynamic change of the proportion of Foxp3-labelled cells.Conclusions The pathogenesis and development is closely associated with the dynamic changes of CD4+ CD25 + Foxp3+ Treg cells in EAU rats.

Decreased production of TNF-alpha by lymph node cells indicates experimental autoimmune encephalomyelitis remission in Lewis rats

Experimental autoimmune encephalomyelitis (EAE) is mediated by CD4+ Th1 cells that mainly secrete IFN-γ and TNF-α, important cytokines in the pathophysiology of the disease. Spontaneous remission is, in part, attributed to the down regulation of IFN-γ and TNF-α by TGF-β. In the current paper, we compared weight, histopathology and immunological parameters during the acute and recovery phases of EAE to establish the best biomarker for clinical remission. Female Lewis rats were immunised with myelin basic protein (MBP) emulsified with complete Freund's adjuvant. Animals were evaluated daily for clinical score and weight prior to euthanisation. All immunised animals developed the expected characteristics of EAE during the acute phase, including significant weight loss and high clinical scores. Disease remission was associated with a significant reduction in clinical scores, although immunised rats did not regain their initial weight values. Brain inflammatory infiltrates were higher during the acute phase. During the remission phase, anti-myelin antibody levels increased, whereas TNF-α and IFN-γ production by lymph node cells cultured with MBP or concanavalin A, respectively, decreased. The most significant difference observed between the acute and recovery phases was in the induction of TNF-α levels in MBP-stimulated cultures. Therefore, the in vitro production of this cytokine could be used as a biomarker for EAE remission.

Left ventricular diastolic dysfunction assessment by tissue Doppler imaging in a suprarenal abdominal aortic coarctation model of Lewis rat / 中华超声影像学杂志

Objective To evaluate the left ventricular diastolic dysfunction by tissue Doppler imaging (TDI)in a suprarenal abdominal aortic coarctation model of Lewis rats. Methods Thirty male Lewis rats at age of 8 weeks were used. Myocardial hypertrophy model was obtained by suprarenal abdominal aorta banding with ligation. Mitral annular velocity measurement by TDI and regular two-dimensional echocardiography with M mode were examined at baseline and at 10-,20-,30-and 40-day post banding.Results Compared with baseline,the left ventricular end diastolic and end systolic wall thickness and ventricular dimension were progressively increased,while ejection fraction(EF)and fraction shortening(FS)were decreased(P＜0.0 1).The left ventricle demonstrated centrifugal myocardial hypertrophy.Peak myocardial systolic velocity(Sa)at the mitral annulus did not change significantly throughout this study and there was no significant correlation with EF(r=0.216,P=0.071),and peak myocardial early diastolic (Ea),late diastolic(Aa)at the mitral annulus and Ea/Aa indices also were not stable after aortic banding and there were no significant difference in repeated measures at different time(P＞0.05).But the E/Ea wasincreased and the index had a statistically significant difference(P＜0.001).Conclusions The left ventricleshowed centrifugal myocardial hypertrophy in Lewis rats with abdominal aortic banding.E/Ea radio was a sensitive and stable index to evaluate left ventricular diastolic dysfunction.