小鼠光性损伤后视网膜神经上皮层移植的初步探讨

Transplantation of neural retina after photic injury of retina in mice

目的探讨光性损伤后视网膜光感受器能否被拯救的可能性。方法用自制的光损伤箱建立视网膜光性损伤的小鼠模型，将光照后的６０只小鼠分为２组，Ⅰ组２０只为光损伤组，Ⅱ组４０只为移植组，又将Ⅱ组分为ⅡＡ组２０只鼠和ⅡＢ组２０只鼠，分别于光性损伤后２４ｈ（ⅡＡ组）和１周（ⅡＢ组）用外经路方法行视网膜神经上皮层移植，分别于术后６、１２、１８及３０天时处死受体鼠，用光镜检查移植物是否能拯救光性损伤后受体鼠视网膜的光感受器。结果Ⅰ组，可见光感受器的内外节被破坏，出现水肿、碎解、空泡变，外核层排列紊乱，核质固缩、边聚，核层明显变薄。Ⅱ组，光性损伤后，ⅡＡ及ⅡＢ组移植物的存活率分别为５０％（１０／２０只眼）及８０％（１６／２０只眼），两组间比较差异有显著性（χ２＝３９５６，Ｐ＜００５）。在移植物存活的标本中，对受体鼠视网膜光感受器的拯救率：ⅡＡ组为４０％（４／１０只眼），ⅡＢ组为５０％（８／１６只眼），两组间比较差异无显著性（Ｐ＝０７０２）。结论光性损伤可导致视网膜光感受器的退行性变性。用视网膜移植的方法可拯救这种退行性变性，其视网膜移植的时间应在光性损伤后１周。

Objective To examine the possibility of retinal photoreceptors rescued after photic injury by allogeneic neural retinal transplantation. Methods The retinal photic injury model was established by a lightdamage trunk designed by ourselves. After photoillumination, 60 mice were divided into two groups: Group I (n=20) was the photic injury group and group (n=40), the retinal transplantation group; then group was subdivided into A (n=20) and B (n=20) subgroups. External approach for neural retinal transplantation was performed at 24hr (group A) and day 7 (group B) after photic injury respectively. The recipients were sacrificed at day 6, day 12, day 18 and day 30 postoperatively to examine whether the graft could rescue the injured retinal photoreceptors. Results In group , the inner and outer segment showed edema, disorganization and vesiculation, the outer nuclear layer became very thin and disorganized, and the cell nuclear chromatin showed pyknosis and margination. In group , the graft survival rate in group A was 50% (10/20) and in group B was 80% (16/20), the difference being significant (2=3956, P<005). Among the graft survival samples, we compared the rescue rate of photoreceptors between group A 40% (4/10) and group B 50% (8/16), the difference being not significant (P=0702). Conclusion The retinal photic injury may result in photoreceptor degeneration that can be rescued by retinal transplantation, and the successful rate of the transplantation performed at day 7 is higher than that at 24hr after injury.