Objective To observe the inhibition effect of the hypoxia inducible factor-1alpha; (HIF-1alpha;) specific siRNA on the expression of vascular endothelial growth factor (VEGF) mRNA in retinal tissues in diabetic rat. Methods This is a randomized controlled study. HIF-1alpha; specific siRNA recombinant plasmid was built in pSilencer2.1-U6neo vector. Fifty-four healthy Sprague Dawley (SD) rats were divided into control group (15 rats) and experimental group (39 rats). The experimental rats were induced with streptozotocin injection for diabetic retinopathy model, and then randomly divided into diabetic retinopathy (DR) group (15 rats), vector group (12 rats) and gene therapy group (12 rats). LipofectamineTM2000 mixed with pSilencer2.1-U6neo plasmid or HiF-1alpha; siRNA plasmid were injected into the vitreous in the vector group and gene therapy group respectively. Nothing was transfected into DR and control group. The expression of VEGF mRNA in retinas was measured by real-time RT-PCR. The inhibition efficiency of VEGFmRNA was calculated at 24, 48, 72 hours and 1 week after injection respectively. Significant differences between groups were evaluated by oneway analysis and LSD-t analysis. Results HIF-1alpha; siRNA recombinant plasmid was confirmed by enzyme digestion and sequence analysis. Real-time RT-PCR revealed that the expression of VEGFmRNA was faint in the control group, increased obviously in the DR and vector group, decreased in the gene therapy group. There was no statistically significant between DR and vector group (t=0.669，0.142,0.151，0.025；P=0.514，0.889，0.882，0.980). The expression of VEGFmRNA in the gene therapy group were obviously decreased compared with DR and vector group (t=8.768, 13.695, 11.285, 8.253;P=0.000). The inhibition efficiency of VEGFmRNA was 32.76%, 43.60%, 47.70%, 50.86% at 24, 48, 72 hours and 1 week after injection. Conclusions The expression of VEGFmRNA can be efficiently inhibited by HIF-1alpha; siRNA recombinant plasmid.
Objective To evaluate the visual prognostic factors in vitreoretinal surgery for diabetic tractional retinal detachment (DTRD). Methods 102 eyes of 86 consecutive patients with DTRD underwent vitreoretinal surgery were analyzed retrospectively. All cases diagnosed via indirect ophthalmoscope and B ultrasonic scan after mydriasis. Followup duration varied from 12 to 56 months (mean: 23 months). Best corrected visual acuity (BCVA) and anatomic success were observed postoperatively. The patients were divided into visual acuity improved group and didn't improved group. Ttest, Chisquare test and Multivariate Logistic regression analysis were performed to predict the prognosis of visual acuity. Results After primary vitreoretinal surgery, 87 eyes (85.3%) were anatomically reattached, 15 eyes (14.71%) needed reoperation because of the recurrence of retinal detachment (RD). Postoperative BCVA improved and better than 0.05 in 49 eyes (48.04%), reduced or increased but less than 0.05 in 53 eyes (51.96%). Comparing natural factors between these two groups, only combined cataract surgery and optic nerve atrophy were significant different (chi;2=5.266,9.274;P=0.022,0.002). Among post-operative complications only the RD recurrence was significant different (chi;2=12.059，P=0.000). Multivariate Logistic regression revealed recurrence of RD and optic nerve atrophy were two independent risk factors in the final BCVA (P=0.003,0.041;OR=33.518、4.079). Preoperative PRP was identified as the only protecting variable in the final BCVA(P=0.034，OR=0.270).Conclusion This study revealed recurrence of RD and optic nerve atrophy were two independent risk factors in final BCVA of DTRD patients.