RESUMO
Objective To establish the model of autoimmune dry eye and analyze the level of cytokines and the pathological changes of autoimmune dry eye rabbits treated with human umbilical cord mesenchymal stem cells (MSCs).Methods Twentyfour female New Zealand rabbits were randomly divided into three groups:Normal control group,dry eye group and MSCs treatment group,8 cases in each group.After treated with MSCs for six weeks,the pathological changes were observed,and the expression of Th1 and Th17 cell differentiation related cytokines mRNA in lacrimal gland tissue was detected by real-time quantitative PCR.The percentage of regulatory T cells (CD4 +Foxp3 + cells) in the lacrimal gland and spleen tissues of the dry eye model group and MSCs treatment group was measured by flow cytometry.Results After treatment with MSCs for 6 weeks,HE staining from each rabbit lacrimal gland showed that,the normal control group showed no or only a few lymphocytes;The lacrimal gland cells were atrophied in the dry eye group,the distribution of lymphocyte scattered around the gland and small blood vessels;Compared with dry eye group,the lacrimal gland lymphocyte infiltration reduced in MSCs treatment group,and the cell morphology were better.Compared with dry eye group,lymphocyte infiltration and aggregation in the conjunctival conjunctiva in MSCs treatment group were significantly reduced,the epithelial structure was intact,and the degeneration and atrophy cells were rare.The expression of inflammatory factors including interferon-γ(IFN-γ),Interleukin-17 (IL-17) and transcription factor T-bet mRNA were decreased in MSCs treatment group,there were significant difference compared with dry eye group (all P ＜ 0.05);Thl7 cell associated cytokines IL-17 expression levels were decreased,but no significant difference was found between two groups (P ＞ 0.05);The expression of transcription factor RORrt mRNA in dry eye group was significantly decreased,the difference was statistically significant (P ＜ 0.05).The expression of inflammatory factors TNF-α in the lacrimal gland tissue of MSCs treatment group was significantly lower than that in the dry eye model group,while the expression of the anti-inflammatory factor TGF-β was significantly higher than that in the dry eye model group,and the differences were statistically significant (all P＜0.05).The regulatory T cells (CD4 + Foxp3 + cells) in the lacrimal gland of dry eye model group accounted for 10％ of lymphocytes was,while the treatment group accounted for 27.8％,MSCs group was significantly higher than dry eye group,the difference was statistically significant (P ＜ 0.05).Conclusion MSCs can reduce the histopathological changes of the immune dry eye,and they may have immunoregulatory effects on autoimmune dry eye.The mechanisms of immunomodulatory effects may be related to the balance of inflammatory cytokines and anti-inflammatory cytokines.
RESUMO
Mesenchymal stem cells (MSCs) have good immune regulatory function,can inhibit many immune cell proliferation,direct effects on activation and proliferation of T cell,play a role in immune regulation by Treg cells or by the secretion of soluble factors regulating Thl/Th2 secretion and reaction equilibrium,inhibit the inflammation through the anti-inflammatory,regulation of cytokines expression at the same time,so reduce the expression levels of matrix metalloproteinase-2 and-9,which may promote lacrimal gland tissue damage,and thus play a role in immune regulation.MSCs can reduce the autoimmune dry eye clinical index,recovery secretion function of part lacrimal gland.This article reviews the research advances in inmmmne regulation of MSCs on autoimmune dry eye.