Preliminary study of rabbits as an animal model of mammalian eye transplantation and literature review / Estudo preliminar de coelhos como modelo animal para transplante de olho em mamíferos e revisão da literatura

ABSTRACT Purpose: To describe an innovative animal model of eye transplantation used in rabbits. Methods: six Dutch-belted male rabbits were submitted to lateral orbitotomy in the right eye, wide retrobulbar anatomy exposure, dissection of the structures, identification and distal section of the optic nerve followed by anastomosis either by vicryl (group 1) or fibrin glue (group 2). Electroretinography recording was performed before the section of the optic nerve and every 30 seconds after, to monitor the function of retina. Left eye was used as control group. Results: After optic nerve resection and anastomosis, stable ERG amplitude of the right eye was lost after 302 seconds in group 1 and after 296 seconds on group 2. Left eye kept longer stable ERG amplitude curves. Conclusions: The animal model of whole eye transplantation was effective in describing a novel technique to be used in rabbits, with success of the anatomic procedure. Further studies will clarify the best anastomosis methods and maintenance of function of the receptor organ. Translational relevance: this animal model of whole eye transplantation provides a novel perspective for blind patients and the research models, since we describe a novel mammal animal model. This model can be used as basis of a human model of whole eye transplantation in future studies.

RESUMO Objetivo: Descrever uma técnica cirúrgica inovadora para transplante de olho em um modelo animal em coelhos. Métodos: Seis coelhos machos com Dutch Belted foram submetidos à orbitotomia lateral do olho direito, com ampla exposição da anatomia retrobulbar, dissecção do cone muscular, exposição e secção distal do nervo óptico seguida de anastomose por vicryl (Grupo 1) ou cola de fibrina (Grupo 2). O registro da eletrorretinografia foi realizado antes da secção do nervo óptico e a cada 30 segundos após, para monitorar a função da retina. O olho esquerdo foi usado como grupo controle. Resultados: Após a ressecção do nervo óptico, a estabilidade da amplitude da eletrorretinografia foi perdida no olho direito após 302 segundos no Grupo 1 e após 296 segundos no Grupo 2. O olho esquerdo manteve eletrorretinografia estável por períodos mais longos. Conclusão: O modelo animal de transplante total de olho foi eficaz em descrever uma nova técnica cirúrgica para ser utilizada em laboratório com coelhos, com sucesso do procedimento anatômico. Novos estudos esclarecerão os melhores métodos de anastomose e manutenção da função do órgão receptor.

Effect of intravitreal injection of FK506 on the survival of heteroplastic retinal pigment epithelial cells / 中华眼底病杂志

Objective To investigate effect of intravitreal injection of FK506 on the survival of human retinal pigment epithelial (RPE) cells heteroplastically transplanted into the subretinal space of rabbits. Methods The immortalized human RPE cells were genetically labeled by retrovirus vector carrying a green fluorescent protein (GFP). A total of 50 ?l RPE cells suspension with 4?10 3 cells/?l which expressed GFP were injected into the subretinal space of both eyes of 18 white rabbits and 10 gray rabbits. The left eyes of all of the rabbits were injected of 5 ?l FK506 (5 ?g/?l) intravitreally once a week during the first 5 weeks, then once every other week until the 20 th week and the right eyes were as the control. The histological sections of heteroplastic RPE cells were observed by epifluorescent microscope. Results GFP-expressing cells could be seen after 1 week, 2, 3, 4, 6, 10, 11, 14, 18, 20, 23, 24, 25, 26, 33, and 54 weeks in white rabbits and after 4, 5, 6, 7, 14, 18, 20, and 26 weeks in gray rabbits. The configuration and integrality of the RPE-GFP cells in the left eyes which had been intravitreally injected of FK506 1-14 weeks after transplantation were better than those in the right eyes without injection. After 18 weeks, the condition of heteroplastic cells with few difference in both eyes in 7 white and 3 gray rabbits were found. After 1-6 weeks, focal and disseminated lymphocytes around the choroidal small vessles of right eyes in 6 white and 3 gray rabbits could be seen while the infiltration of the lymphocytes in the left eyes was much reduced. Conclusion Intravitreal injection of a small amount of FK506 at the first 3 months after transplantation may significantly improve the survival of heteroplastic RPE cells in the subretinal space of rabbits.

Methodological study of preparing iris pigment epithelial cells for autologous transplantation in rabbits / 中华眼底病杂志

Objective To explore a better method in obtaining iris pigment epithelium (IPE) specimen for autologous transplantation in rabbits. Methods IPE was obtained from 20 black rabbits with method A, i.e., surgical peripheral iridectomy at 12:00 position obtaining a triangle iris tissue with the hemline of 4-5 mm in left eyes,and method B,i.e., surgical peripheral iridectomy at 11:00 and 1:00 positions obtaining two triangle iris tissues with the hemlines of 2-2.5 mm in right eyes . The IPE cells were isolated precisely with enzyme microdissection-enzyme isolation method, cultured in vitro, observed with light and electronic microscope, and identified with immunocytochemical staining. Results The success rate of cells culture were 65% for method A and 95% for method B. After 3-4 generations of culturing,the amount of IPE cells was enough for transplantation, and most of the functions of primary clutured IPE cells were kept still. Viability of IPE cells was 85%-93%. Conclusion The success rate of cells culture for method B is higher than that for method A. The third generation of cultured cells is available for autologous transplantation.