糖尿病患者血小板游离钙变化与血栓素B2生成的关系

为了探讨糖尿病患者血小板胞浆内游离Ｃａ￣（２＋）浓度（［Ｃａ￣（２＋）］ｉ）与血栓素Ｂ＿２（ＴＸＢ＿２）生成的关系，及其在糖尿病微血管病变发病中的作用，作者用Ｃａ￣（２＋）荧光指示剂ｆｕｒａ－２直接测定２７例糖尿病患者（合并微血管病变苔１３例，无微血管病变者１４例）血小板［Ｃａ￣（２＋）］ｉ，并且同步测定ＴＸＢ＿２。结果：以钙载体Ａ＿（２３１８７）诱导，糖尿病组血小板［（Ｃａ￣（２＋）］ｉ峰值为１１４７±５２ｎｍｏｌ／Ｌ，高于对照组（８９７±４９ｎｍｏｌ／ＬＰ＜０．０１），且与ＴＸＢ，生成呈正相关：而用花生四烯酸诱导，糖尿病组血小板［Ｃａ￣（２＋）］ｉ峰值为３５３±１４ｎｍｏｌ／Ｌ，虽高于对照组（３１２±１６ｎｍｏｌ／Ｌ，Ｐ＜０．０５），但与ＴＸＢ＿２生成未呈显著相关。上述改变在糖尿病有或无微血管病变两组之间比较无显著性差异，提示糖尿病患者血小板［Ｃａ￣（２＋）］ｉ变化可能通过膜磷脂酶环节致使ＴＸＢ＿２生成增多，参与微血管病变的发病。

Changes in cytosolic free calcium and thromboxane B2synthesis in platelets from diabetic subjects

sing fura-2, a fluorescence indicator, we evalu-ated the changes of platelet cytosolic free calcium con-centration([Ca2 ]i)and its role in regulation ofthromboxane B2 (TXB2)synthesis in patients with dia-betes mellitus (DM group, n= 27) and in healthy sub-jects (control group , n= 15). The A23187-evoked eleva-tion of [Ca2 ]i and TXB2 production were higher in theDM group than in the control group (P<0. 01 respec-tively). The rise in [Ca2 ]i was correlated posrtivelywith TXB2 production. In contrast, stimulation witharachidonic acid, TXB2 production was unaltered be-tween the groups, ahhough arachidonate-induced[Ca2 ]i was higher in the DM group than in the controlgroup(P<0. 05).The results suggested that changesin platelets [Ca2 ]i in diabetic subjects may contributeto increase in TXB2 synthesis , involved libration of freearachidonate from membrance phospholipids by the ac-tion of phospholipases. Since no significant differencewas found between the diabetic patients with microan-giopathy (n= 137 and without microangiopathy (n =14) , the results above may be involved in the develop-ment of diabetic microangiopathy.