Abstract
Purpose: :
To investigate the differentiation potency of engrafted mesenchymal stem cells to the new retinal cell population through the in vivo ischemia-reperfusion injury model of rat.
Methods: :
Sprague-Dawley rats, 8 weeks of age, were used for the present study. Glaucoma-like ischemic injury model was made by an elevation of intraocular pressure by injecting the air through needle inserted into the anterior chamber. Bone marrow derived stem cells passed for three generations were used. Stem cells labeled with DiI were applied with an intravitreous injection at 3, 5 and 7 days after the ischemia-reperfusion injury (PI), respectively, based on the previous studies, and cared for 14 days. For specification of stem cells, double immunostaining with retinal neuronal markers was done. The results were evaluated by light microscopy and confocal microscopy.
Results: :
Retinal ischemia led to reduce in both thickness and cell number, principally in the inner retina and to a lesser extent in the outer retina. Intravitreously injected DiI-labeled stem cells were migrated and well associated with host retinal tissue. Stem cell application alleviated ischemia-reperfusion induced damage to the retina, especially to the inner retina. The retinas of stem cell injected groups were thicker than those of the group received ischemia injury only. Among three stem cell injection groups (3d, 5d, and 7d PI), the most engrafted population of stem cells appeared in the retinas of 7d PI. Engrafted stem cells were observed mainly in the ganglion cell layer. In double immunofluorescent staining of the retinas, there was no colocalization of DiI and neuronal markers.
Conclusions: :
These results demonstrate that engrafted mesenchymal stem cells are not differentiated into any retinal cell population and these cells pass through the broken blood retina barrier followed by neuronal degeneration in response to ischemia-reperfusion injury. The present retina ischemic model of rat is useful for investigation of glaucoma pathophysiology.
Keywords: retina • ischemia • transplantation