Objective To observe the survival of human umbilical cord derived mesenchymal stem cells (hUC-MSCs) after injection into the vitreous of rabbits,and the animal safety under those procedures.Methods Twentyseven pigmented rabbits were randomly divided into 3 groups (intravitreal injection 1 week group，2 weeks group and 4 weeks group)， each with 9 rabbits.For each animal the right eye was the experimental eye receiving hUCMSCs injection,while the left eye was the control eye receiving culture medium. The rabbit eyes were examined by slitlamp microscope, indirect ophthalmoscopy, fundus photography, fundus fluorescence angiography（FFA）and Tonopen tonometer before and after injection. hUCMSCs were labeled by CMDil in vitro, and their survival status was measured by confocal fluorescence microscopy, light microscope and transmission electron microscope at 4 weeks after injection. Results Four weeks after injection, a large number of the hUCMSCs were still alive in the vitreous cavity. The overall condition of those rabbits was good. The anterior segment and retina of experimental eyes were normal, without hyperfluorescence, hypofluorescence and leakage in the retina at 1,2 and 4 weeks after injection. There was no significant difference on IOP before and after injection at different time points (P＞0.05), and no obvious changes at cornea, anterior chamber angle,lens,retinal structure by.light microscope and transmission electron microscope examination.Conclusion hUC-MSCs can survive in the rabbit vitreous for four weeks；intravitreal injection of hUCMSCs was safe and feasible.
ObjectiveTo observe the retinal microcirculation changes in chinchilla rabbit with branch retinal vein occlusion (BRVO), and to evaluate the feasibility of laser speckle imaging (LSI) technology as monitoring tool for retinal microcirculation. MethodsTen 4-month-old chinchilla rabbits were used for the experiment, selecting the right eye as the experimental eye. The main retinal vein, adjacent 0.5-1.0 mm to the optic of rabbit retina, was selected to the target vessel under surgical microscope. The software of LSI instrument was used to measure the diameter of target vein and blood flow of 0.2 mm2 area of target vein. The BRVO rabbit model was induced by photodynamic therapy, then measure the diameter and blood flow in the same region using the method as before and after 10 minutes modeled. ResultsThe retinal color pictures, infrared laser and the distribution of blood flow pseudo-color were synchronous displayed by LSI technology. Before and after modeling, the target vessel diameter were (0.104±0.009), (0.128±0.008) mm, and the 0.2 mm2 area blood flow of target vessel were (563.500±28.788), (256.000±53.319) PU. The diameter of target blood vessel after modeling was significantly thicker than before, with the significant difference (t=12.14,P=0.008). The blood flow in 0.2 mm2 area of target vessel was significantly lower than before, also with the significant difference (t=183.00,P=0.009). ConclusionsThe diameter of target vessel of the BRVO rabbit model is enlarged, and the target vessel area of 0.2 mm2 blood flow is reduced significantly. LSI system can monitor the retinal microcirculation real-time and quantitatively.