Cyclosporine A (CsA) is associated with posttransplantation bone disease. Immunosuppressant drugs such as sirolimus (SRL), which are more potent and less deleterious than CsA, are being developed. Previous experiments have shown that SRL although immunosuppressive, is relatively bone sparing. The use of low doses of CsA and SRL in combination has displayed in vivo synergism. This study was initiated to examine the effect of low‐dose CsA and SRL on bone metabolism, thereby hopefully providing a bone sparing immunosuppressive regimen for transplant recipients. One hundred and nineteen rats were divided into groups: basal, vehicle, CsA high dose, CsA low dose, SRL low dose, and combination low‐dose CsA and SRL. The basal group was killed on day 0 for histomorphometry. The experimental groups were weighed and bled on days 0, 28, 56, and 84 and were killed on day 84 for histomorphometry. Serial assays for blood urea nitrogen (BUN), creatinine, and osteocalcin were performed. Osteocalcin was raised on days 28 and 56 in the high dose CsA group. Histomorphometry showed osteopenia with high‐dose CsA. Low‐dose CsA was relatively bone sparing, while low‐dose SRL and combined low‐dose CsA did not cause bone loss. In conclusion, the synergistic combination of low‐dose CsA and SRL has the potential of providing both bone sparing and immunosuppressive benefits.
环孢素 A(CsA)与移植后骨病有关。与 CsA 相比,
西罗莫司(SRL)等
免疫抑制剂药效更强、危害更小,目前正在开发中。以前的实验表明,SRL 虽然具有免疫抑制作用,但相对来说不影响骨质。低剂量 CsA 和 SRL 的联合使用在体内显示出协同作用。本研究旨在探讨低剂量 CsA 和 SRL 对骨代谢的影响,从而为移植受者提供一种疏松骨质的免疫抑制方案。实验将 119 只大鼠分为几组:
基础组、载体组、CsA 大剂量组、CsA 小剂量组、SRL 小剂量组以及 CsA 和 SRL 联合小剂量组。
基础组在第 0 天处死,以进行组织形态计量。实验组在第 0、28、56 和 84 天进行称重和放血,并在第 84 天处死,以测定组织形态学。对血
尿素氮(BUN)、
肌酐和骨
钙素进行连续检测。高剂量 CsA 组的骨
钙素在第 28 天和第 56 天升高。组织形态测量显示,高剂量 CsA 会导致骨质疏松。低剂量 CsA 对骨质的影响相对较小,而低剂量 SRL 和联合低剂量 CsA 不会导致骨质流失。总之,小剂量 CsA 和 SRL 的协同组合有可能同时具有疏松骨质和免疫抑制的作用。