Abstract
Purpose: :
Bone marrow cells (BMCs) have been used as a source of many kinds of mature cells including retinal cells in regenerative medicine research. We previously reported that BMCs were able to differentiate into retinal cells in injured rat retina and into a part of choroidal neovascularization induced by laser photocoagulation. In this study, we investigated whether BMC transplantation into the eye can accelerate recanalization of retinal vasculature which previously was lost due to hyperoxic stress.
Methods: :
C57 bl/J mouse pups were used. At P7, mice were separated into 3 groups. One group was injected with whole BMCs isolated from adult mice (BMCs@P7), one group was injected with saline (saline@P7), and one group received no treatment (control@P7). Then, mice were set into an oxygen chamber containing 75% oxygen. After oxygen exposure for 5 days, the mice were sacrificed. Some control@P7 mice were moved to a normoxic environment and divided into 3 sub–groups, which were saline–injected (saline@P12), BMC–injected (BMCs@P12), and no treatment (control@P12). These mice were kept for 5 more days with normoxia and were sacrificed at P17. At the time of sacrifice, one eye of each animal was enucleated following perfusion with fluorescein dextran and a retinal flat mount was prepared to measure vascular non–perfusion area (VNPA).
Results: :
The VNPAs of control@P7 mice was the highest. The VNPAs of saline@P7 and BMCs@P7 mice were at the same level but statistically smaller than that of control@P7 mice. The VNPAs of saline@P12 mice was statistically smaller than those of control@P7, saline@P7, BMCs@P7 mice. BMCs@P12 mice had no VNPA and this result was statistically different from all other groups.
Conclusions: :
BMCs augmented recanalization of retinal vasculature. The effect of vascular recanalization by BMCs was not seen following P7 injection but was seen following P12 injection. These results suggest that accelerated vascular reconstruction was due not to a component of BMCs but to BMCs themselves that differentiated into vascular cells. Transplantation of BMCs may be a useful treatment for NPAs in hypoxic retinopathies like diabetic retinopathy and retinopathy of pre–maturity.
Keywords: neovascularization • retina • ischemia