Cyclosporin A (CsA, Cyclosporine, Antibiotic S 7481F1, Ramihyphin A, NSC 290193)，又称为环孢霉素A、环孢素A、环孢多肽A、环孢灵、赛斯平、环孢素等，是由丝状真菌产生的环状寡肽，由 9 个氨基酸组成。Cyclosporin A抑制T细胞受体信号转导通路，过程为：与亲环素结合后，形成Cyclosporin A-亲环素复合物，抑制钙调磷酸酶(Calcineurin)-磷酸酶2B (PP2)的酶活性，IC₅₀为7 nM。此外，Cyclosporin A与线粒体亲环蛋白结合抑制线粒体通透性转化孔(mitochondrial permeability transition pore, MPTP)的形成和开放，但该抑制作用是瞬时的，可通过提高Ca²⁺载量被解除。在PC-12细胞实验中，Cyclosporin A还抑制鱼藤酮(rotenone)诱导的凋亡。

作为一种免疫抑制剂，Cyclosporin A可以抑制细胞介导的免疫反应，包括同种异体移植、迟发型皮肤过敏及T细胞依赖性抗体的产生等。目前广泛用于预防器官移植反应中的排斥反应。

参考文献

[1].Salisbury, J.D., et al. Suppression of corneal allograft rejection by cyclosporin A. Arch Ophthalmol 99(9): 1640-1643(1981).

[2].Palacios, R., et al. Cyclosporin A blocks receptors for HLA-DR antigens on T cells. Nature 290(5809): 792-794(1981).

[3].Handschumacher, R.E., et al. Cyclophilin: a specific cytosolic binding protein for cyclosporin A. Science 226(4674): 544-547(1984).

[4].Liu, J., et al. Calcineurin is a common target of cyclophilin-cyclosporin A and FKBP-FK506 complexes. Cell 66(4): 807-815(1991).

[5].Fruman DA, et al. Calcineurin phosphatase activity in T lymphocytes is inhibited by FK 506 and cyclosporin A. Proc Natl Acad Sci U S A 89(9): 3686-3690(1992).

[6].Halestrap, A.P., et al. Cyclosporin A binding to mitochondrial cyclophilin inhibits the permeability transition pore and protects hearts from ischaemia/reperfusion injury. Mol Cell Biochem 174(1-2): 167-172(1997).

[7].Seaton, T.A., et al. Cyclosporin inhibition of apoptosis induced by mitochondrial complex I toxins. Brain Res 809(1):12-17(1998).

[8].Kim SY, et al. Inhibition of cyclophilin D by cyclosporin A promotes retinal ganglion cell survival by preventing mitochondrial alteration in ischemic injury. Cell Death Dis. 5(3): e1105 (2014).

冰袋运输。粉末直接保存于-25~-15℃，有效期2年。建议避光干燥保存，避免反复冻融。