Nature：注射感光细胞有助视力恢复

4月18日，英国伦敦大学等处的研究人员在Nature杂志网站上报告说，通过向一些视力受损的实验鼠注射感光细胞，就能在一定程度上帮助它们恢复视力，将来有望在此基础上开发出治疗人类失明的方法。
 
英国伦敦大学学院等机构研究人员报告，在本次实验中注射的是视杆细胞的前体细胞。视杆细胞是视网膜中的两种感光细胞之一，它对微弱光线特别敏感，老鼠虽然通常在晚上视力不错，但如果缺少这种细胞，在黑暗环境中也是“睁眼瞎”，本次接受注射的就是这种视力有缺陷的实验鼠。
 
前体细胞是尚未完全成熟的视杆细胞，在本次实验中，研究人员从年轻健康的实验鼠中提取了视杆细胞的前体细胞，然后将其注入到视力受损实验鼠的视网膜中。结果在4到6个星期后，这些细胞与视网膜中的神经组织建立了联系，开始像正常的视杆细胞那样发挥作用。
 
测试也表明这些实验鼠的视力有所恢复。它们被放入一个黑暗的简单迷宫中，出口处有微弱的光线，接受治疗的实验鼠可以很快找到出口，没有接受治疗的实验鼠在四处碰壁后才会偶然找到出口。
 
领导研究的罗宾·阿里教授说，这是首次证实移植的感光细胞可以融入到视网膜中并改善视力，如果这一效果将来在人类临床试验中能够重现，将是失明患者的福音。
 
视网膜中的感光细胞包括视杆细胞和视锥细胞，它们出现缺陷会导致多种引起失明的疾病，如老年黄斑变性、色素性视网膜炎和与糖尿病有关的失明等。研究人员表示，还会利用视锥细胞进行实验，以探索更全面的改善视力的方法。

doi:10.1038/nature10997
PMC:
PMID:

Restoration of vision after transplantation of photoreceptors

R. A. Pearson, A. C. Barber, M. Rizzi, C. Hippert, T. Xue, E. L. West, Y. Duran, A. J. Smith, J. Z. Chuang, S. A. Azam, U. F. O. Luhmann, A. Benucci, C. H. Sung, J. W. Bainbridge,1 M. Carandini, K.-W. Yau, J. C. Sowden & R. R. Ali

Cell transplantation is a potential strategy for treating blindness caused by the loss of photoreceptors. Although transplanted rod-precursor cells are able to migrate into the adult retina and differentiate to acquire the specialized morphological features of mature photoreceptor cells1, the fundamental question remains whether transplantation of photoreceptor cells can actually improve vision. Here we provide evidence of functional rod-mediated vision after photoreceptor transplantation in adult Gnat1?/? mice, which lack rod function and are a model of congenital stationary night blindness2. We show that transplanted rod precursors form classic triad synaptic connections with second-order bipolar and horizontal cells in the recipient retina. The newly integrated photoreceptor cells are light-responsive with dim-flash kinetics similar to adult wild-type photoreceptors. By using intrinsic imaging under scotopic conditions we demonstrate that visual signals generated by transplanted rods are projected to higher visual areas, including V1. Moreover, these cells are capable of driving optokinetic head tracking and visually guided behaviour in the Gnat1?/? mouse under scotopic conditions. Together, these results demonstrate the feasibility of photoreceptor transplantation as a therapeutic strategy for restoring vision after retinal degeneration.