早期糖尿病视网膜血流动力学改变的实验研究

目的 :利用彩色多普勒探讨早期糖尿病视网膜病变 (Diabetic Retinopathy,DR)发生和发展过程中视网膜的血流动力学变化。方法 :雄性成年 Wister大鼠 74只随机分为实验组和正常对照组 ,实验组经链脲佐素腹腔注射诱导成糖尿病大鼠模型。两组大鼠均分别于 4周、 8周和 12周时行彩色多普勒超声检查测量大鼠视网膜中央动脉 (CRA)的血流动力学 ,分析其收缩期最大流速 (Vmax)、舒张期最小流速 (Vmin)、 E/ P(Vmin/ Vmax)、阻力指数 (RI)和搏动指数 (PI)的变化。检查完毕即摘除大鼠眼球 ,行视网膜血管消化铺片的制作和观察。结果 :4周时实验组大鼠 CRA血流动态与正常对照组无显著性差异 ;8周时 ,实验组大鼠 Vmax、Vmin以及 E/ P均明显低于同期正常对照组 (P<0 .0 5) ;12周时 ,与同期正常对照组相比 ,实验组大鼠 CRA血流的 Vmax、 Vmin及 E/ P明显降低 (P<0 .0 5) ,RI和 PI显著增高 (P<0 .0 5)。而光镜下实验组大鼠的视网膜血管消化铺片观察仅在 12周发现视网膜的早期病变。结论 :在早期糖尿病 ,彩色多普勒检查可于视网膜血管病变出现之前早期发现视网膜血流动力学异常 ,提示视网膜血流供应和灌注的不良可能在 DR的发生和发展过程中起着重要作用

Hemodynamic Changes in Early Stage of Diabetic Retinopathy in Rats

Objective:To investigate the hemodyna mic ch anges in early stage of diabetic retinopathy (DR) in rats with color Doppler ima ging (CDI).Methods:Seventy-four Wister rats were divided into two g roup s:normal control and diabetic group Diabetic rats were induced by abdomen-inje cted Stroptozacin CDI was performed in 4 week,8 week and 12 week courses to mea sure systolic peak velocity (Vmax),end diastolic velocity (Vmin),E/P (Vmin/Vmax) ,resistance index (RI) and pulsitile index (PI) of central retinal artery (CRA) Then,the eyes of the diabetic rats were dissected to make retinal digest prepa rations.Results:There was no significant difference of CRA hemodyn am ics between diabetic and normal rats in 4 weeks In 8 weeks,Vmax,Vmin and E/P o f CRA were significantly lower in diabetic rats than those in normal rats (P <0 05) In 12 weeks,besides the significantly lower Vmax,Vmin and E/P,diabeti c rats had higher PI and RI of CRA than those of normal rats (P<0 05 ) In contrast,early changes of DR were only demonstrated in 12 week diabetic r ats in retinal digest preparations.Conclusions:CDI can detect hemodynamic abnormality of CRA before the appearance of early DR It is suggested that the insufficiency of blo od flow in retina be one of the important factors that influent thedevelo-pment of DR.