穿膜肽TAT蛋白介导非促分裂酸性成纤维细胞生长因子治疗大鼠糖尿病视网膜病变的疗效及机理研究

Acidic fibroblast growth factor (aFGF), as one kind of neurotrophic factors, can be potentially used for the treatment of diabetic retinopathy (DR). However, because of the presences of blood-ocular barrier and plasma protein, aFGF can not reach the therapeutic concentration in retina after topical or systematic use. In our previous study, we succeeded in developing a non-invasive ocular drug delivery system with TAT protein, which was derived from HIV. TAT-conjugated aFGF exhibited efficiency in treating ischemia-reperfusion injury in rats. However, recent reports have shown that the mitogenic activity of aFGF contributed to several human pathologies, including proliferative retinopathy. To decrease the potential side-effects of aFGF caused by its broad-spectrum mitogenic activity, a shortened non-mitogenic form of aFGF (aFGF28-154) was constructed genetically in our early study. The aFGF28-154 decreases its mitogenic activity, but retains its neuroprotective properties. In the present study, we investigated the pharmacological effect of TAT-aFGF28-154 in DR model, including its interaction with FGFR, signaling mechanisms, scotopic electroretinogram function, histological changes, cell apoptosis，as well as its effects on retinal vascular neogenesis. In addition, we will try to illustrate the mechanism how TAT mediated the delivery of macroproteins to the retina following topical administration to the ocular surface. In summary, our data will help to raise a new treatment protocol for DR in clinic.

酸性成纤维细胞生长因子(aFGF)具有治疗糖尿病视网膜病变（DR）的功能。然而受血-眼屏障、血浆蛋白结合等因素影响，局部滴用以及全身给药aFGF均难以在视网膜达到有效药物浓度。在早期研究中，我们利用穿膜肽（TAT）蛋白作为载体，携带aFGF用于无创性治疗视网膜病变。然而，aFGF的促有丝分裂活性存在诱发增殖性视网膜病变的风险。为此，本课题组制备了非促分裂aFGF（aFGF28-154），降低其诱发增殖性视网膜病变的副作用，保留了它对神经的营养再生功能。以此为基础，本研究设想以DR为模型，研究TAT-aFGF28-154对受体作用、信号激活、视网膜电图、视网膜组织病理学改变、视网膜细胞凋亡以及视网膜血管新生的影响，并进一步探讨TAT-aFGF28-154穿透眼球屏障的途径及作用机理，完善使用非损伤性手段治疗眼底疾病的方法，以期为临床上防治DR提出新的有效措施。

酸性成纤维细胞生长因子(aFGF)具有治疗糖尿病视网膜病变（DR）的功能。然而受血-眼屏障、血浆蛋白结合等因素影响，局部滴用以及全身给药aFGF均难以在视网膜达到有效药物浓度。在早期研究中，我们利用穿膜肽（TAT）蛋白作为载体，携带aFGF用于无创性治疗视网膜病变。然而，aFGF的促有丝分裂活性存在诱发增殖性视网膜病变的风险。为此，本课题组制备了非促分裂aFGF（aFGF28-154），降低其诱发增殖性视网膜病变的副作用，保留了它对神经的营养再生功能。本研究以DR为模型，研究TAT-aFGF28-154对受体作用、信号激活、视网膜电图、视网膜组织病理学改变、视网膜细胞凋亡以及视网膜血管新生的影响。我们的结果发现，TAT作为载体，可以运载生物大分子aFGF及aFGF28-154从角膜进入，通过房水渗透到眼底视网膜组织。TAT-aFGF28-154降低了高糖对视神经节细胞的损伤，从DR早期开始，有效抑制视网膜病变的进一步恶化。我们的研究完善了使用非损伤性手段治疗眼底疾病的方法，为临床上防治DR提出新的有效措施。