Inhibitory effect of an angiotensin II receptor antagonist in diabetic retinopathy

背景：定量评价氯沙坦对糖尿病大鼠视网膜微循环白细胞滞留的治疗效果。方法：注射链脲佐菌素诱导糖尿病后，将大鼠分为2个亚组。第一亚组（n=6），未接受药物治疗；第二亚组（n=6）给予新鲜饮用水加氯沙坦（5mg/kg/天），连续4周。6只未注射STZ或未给予药物的大鼠作为对照。干预后4周，用吖啶橙数字荧光法观察视网膜白细胞动态。比较三组间视网膜白细胞夹持情况。结果：与对照组（2.8（1.2）个细胞/mm2， p=0.005）和氯沙坦治疗组（3.1（0.9）个细胞/mm2， p=0.0002）相比，未治疗组糖尿病大鼠捕获的白细胞数量（6.1（SD1.4）个细胞/mm2）明显增加。结论：氯沙坦是一种AT1血管紧张素II受体拮抗剂，可抑制糖尿病视网膜中白细胞的增加。作者证明氯沙坦可能具有预防糖尿病视网膜病变发展的治疗效果。血管紧张素受体拮抗剂对糖尿病视网膜病变的预防作用有待进一步的临床研究。

Background : The effectiveness of losartan for the treatment of leukocyte entrapment in the retinal microcirculation of diabetic rats was evaluated quantitatively.Methods : After diabetes was induced by injection of streptozotocin(STZ), the rats were divided into two subgroups. The first subgroup(n=6), received no medications ; the second subgroup(n=6) was given fresh drinking water supplemented with losartan(5mg/kg/day) for 4 weeks. Six rats that were not injected with STZ or given medications served as controls. 4 weeks after intervention leukocyte dynamics in the retina were observed using acridme orange digital fluorography. Leukocyte entrapment in the retina was compared among the three groups.Results : In the untreated diabetic rats, the number of trapped leukocytes(6.1(SD1.4)cells/mm2) increased significantly compared with control rats(2.8(1.2) cells/mm2;p=0.005) and diabetic rats treated with losartan(3.1(0.9)cells/mm2;p=0.0002).Conclusions : Losartan, an AT1 angiotensin II receptor antagonist, inhibited increased leukocyte entrapment in the diabetic retina. The authors demonstrated that losartan may have therapeutic efficacy in preventing development of diabetic retinopathy. Futher clinical studies of the effect of the angiotensin receptor antagonist on preventin development of diabetic retinopathy are needed.