de Franceschi L, Rouyer-Fessard P, Alper S L, Jouault H, Brugnara C, Beuzard Y
Department of Internal Medicine, University of Verona, Italy.
Blood. 1996 Feb 1;87(3):1188-95.
beta thalassemia (beta thal) in DBA/2J mice is a consequence of the spontaneous and complete deletion of the beta major globin gene. Homozygous beta thal mice have clinical and biological features similar to those observed in human beta thal intermedia. Erythrocytes in human beta thal are characterized by a relative cell dehydration and reduced K+ content. The role of this erythrocyte dehydration in the reduced erythrocyte survival, which typifies the disease, has not previously been evaluated. We examined for 1 month the effects on the anemia and the erythrocyte characteristics of beta thal mice of daily treatment with either clotrimazole (CLT), an inhibitor of red blood cell (RBC) dehydration via the Gardos channel, or human recombinant erythropoietin (r-HuEPO), or hydroxyurea (HU). The use of either r-HuEPO or HU induced a significant increase in hemoglobin (Hb), hematocrit (Hct), erythrocyte K+ and a decrease in percent reticulocytes, suggesting improved erythrocyte survival. CLT alone decreased only mean corpuscular hemoglobin concentration (MCHC) and cell density and increased cell K+. Thus, though the Gardos channel plays a major role in cell dehydration of murine beta thal erythrocyte survival. Combination therapy with r-HuEPO plus HU produced no incremental benefit beyond those of single drug therapy. However, addition of CLT to r-HuEPO, to HU, or to combined r-HuEPO plus HU led to statistically significant increase in Hb, Hct, and erythrocyte K+ compared with any of the regimens without CLT. These results suggest that CLT not only inhibits erythrocyte dehydration, but also potentiates the erythropoietic and cellular survival responses to r-HuEPO and HU.
DBA/2J小鼠中的β地中海贫血（β地贫）是β-珠蛋白基因自发且完全缺失的结果。纯合β地贫小鼠具有与人类中间型β地贫相似的临床和生物学特征。人类β地贫中的红细胞以相对细胞脱水和钾离子含量降低为特征。这种红细胞脱水在典型的该疾病红细胞存活减少中的作用此前尚未得到评估。我们用克霉唑（CLT，一种通过加德什通道抑制红细胞脱水的抑制剂）、重组人促红细胞生成素（r-HuEPO）或羟基脲（HU）对β地贫小鼠进行每日治疗，持续1个月，以研究其对贫血和红细胞特征的影响。使用r-HuEPO或HU均可显著提高血红蛋白（Hb）、血细胞比容（Hct）、红细胞钾离子水平，并降低网织红细胞百分比，提示红细胞存活得到改善。单独使用CLT仅降低平均红细胞血红蛋白浓度（MCHC）和细胞密度，并增加细胞钾离子水平。因此，尽管加德什通道在小鼠β地贫红细胞存活的细胞脱水中起主要作用。r-HuEPO加HU的联合治疗并未产生超出单一药物治疗的额外益处。然而，与任何不含CLT的治疗方案相比，在r-HuEPO、HU或r-HuEPO加HU联合治疗中添加CLT可导致Hb、Hct和红细胞钾离子水平在统计学上显著升高。这些结果表明，CLT不仅抑制红细胞脱水，还增强了对r-HuEPO和HU的促红细胞生成和细胞存活反应。
