The Inhibitory Effects Of Shikonin On T Cells And Its Mechanism

Objectives:Organ transplantation is an effective and ultimate treatment for patients with end-stage organ failure.However,almost all patients undergoing organ transplantation require continuous immunosuppressive therapy.Therefore,immunosuppressive agents play a vital role in maintaining the survival of allografts.However,long-term use of immunosuppressive agents will also cause serious side effects.Hence,it is necessary to search for novel immunosuppressive agents that may provide high efficiency in immunosuppression with minimal side effects.Shikonin is a bioactive naphthoquinone pigment originally extracted from the root of Lithospermum erythrorhizon,has been shown to regulate immunity and inflammatory responses.Importantly,shikonin has been proved to suppress human T lymphocyte activation via suppressing JNK signaling and IKKβ activity.But it remains unknown whether shikonin modulates alloimmunity and suppresses allograft rejection.In this study we explored the inhibitory effects of shikonin on T cells and its potential mechanism at cytological level,and its effect on allogeneic heart transplantation,laying the foundation for the future study of its allograft response.Methods:First,we explored whether shikonin can inhibit the proliferation of lymphocytes in vitro through lymphocyte transformation experiments and CFSE staining experiments;then,we conducted clonal anergy,FITC-Annexin V/PI staining experiments,cell cycle detection and induction regulatory T cell experiments have explored the potential mechanism of shikonin in inhibiting lymphocyte proliferation at a cellular level.Last,we established a mice allogeneic heart transplantation model and then explored the effect of shikonin on heart grafts survival time.Results:Through the lymphocyte transformation experiment and the CFSE proliferation detection,we found that shikonin could effectively inhibit the proliferation of lymphocytes in vitro,and this inhibitory effect was dose-dependent.In vitro,cytology experiments revealed that shikonin exerted it’s effects by inducing lymphocyte apoptosis,inducing regulatory T cell production and blocking the cell cycle.In vivo,shikonin administration group prolonged the survival period of mice allogeneic heart transplants.Conclusions:Our results showed that,shikonin could inhibit the proliferation of lymphocytes through a variety of mechanisms in vitro.Shikonin could prolong the survival period of mice heart grafts in vivo.In summary,shikonin has the potential to become a highly effective immunosuppressant.