糖尿病大鼠视网膜早期病变中PDGF-B的表达

Expression of PDGF-B in retina of rats with early-stage diabetic retinopathy

目的:探讨血小板源生长因子-B(PDGF-B)mRNA表达水平在糖尿病(DM)大鼠视网膜中的变化规律及其作用.方法:雄性W istar大鼠60只,随机分为正常对照组(25只)与造模组(35只).造模组以链脲佐菌素(STZ)尾iv,3 d后测定血糖≥16.7 mmol/L,尿糖以上者定为DM大鼠.分别于造模成功后1,2,3 mo末各组随机取6只大鼠,采用半定量逆转录-聚合酶链反应(RT-PCR)方法检测PDGF-B mRNA在大鼠视网膜中的表达水平;电镜观察DM大鼠视网膜超微结构的改变.结果:随着病程的延长,视网膜中PDGF-B mRNA表达水平在DM组明显升高,与正常对照组相比于造模后1 mo末时即差异具有统计学意义(P<0.05),3 mo末时差异显著(P<0.01);DM大鼠视网膜超微结构的损害随病程进展逐渐加重.结论:PDGF-B mRNA在视网膜中的表达水平随DM病程进展逐步升高.

AIM ： To observe the expression of platelet-derived growth factor-B chain （PDGF-B） mRNA in the retina of diabetic rats at the early stage of diabetic retinopathy. METHODS： A total of 60 healthy adult male Wistar rats were randomly divided into control and diabetic groups. Streptozotocin （60 mg/kg） was injected into the tail vein to induce diabetes in 3.5 rats in diabetic group, while 2.5 rats in control group were treated with the same volume of citric acid buffer solution. On the 3rd day after injection, the rats whose urine glucose was more than ＋ ＋ and fasting blood glucose t〉 16.7 mmol/L were chosen as laboratory objects. At the end of 1st, 2nd and 3rd months, 6 rats in both groups were randomly sacrificed and the retinas were dissected and total RNA was isolated for the detection of mRNA for PDGF-B by semi-quantitative reverse-transcription polymerase chain reaction （ RT-PCR ）. The retinas of the other rats in both groups were taken and prepared as the ultrathin and observed by transmission electron microscope. RESULTS： The levels of mRNA encoding PDGF-B in the retinas of diabetic rats were significantly higher than those in controls at each observed time point （ P〈0.0.5 or P〈0.01 at the end of 1st and 3rd month）. Obvious ultrastructural damages, which were in relation to the course of diabetes, could be seen in the retinas of diabetic rats. CONCLUSION： Diabetes upregulates PDGF-B mRNA levels in the retinas of diabetic rats in a time-dependent manner.