Human Umbilical Mesenchymal Stem Cell Xenografts Repair UV-Induced Photokeratitis in a Rat Model.

Most patients with a corneal injury are administered anti-inflammatory medications and antibiotics, but no other treatments are currently available. Thus, the corneal injury healing is unsatisfactory, affects the vision, and has a risk of blindness in severe cases. Human umbilical mesenchymal stem cells exhibit pluripotent and anti-inflammatory properties and do not cause immunological rejection in the host. Rats were irradiated with type B ultraviolet (UVB) light to generate a stable animal model of photokeratitis. After irradiation-induced photokeratitis, human umbilical mesenchymal stem cells were implanted into the subconjunctival space of the lateral sclera, and the changes in the corneal pathology were evaluated. Three weeks after implantation, many mesenchymal stem cells were visible in the subconjunctival space. These mesenchymal stem cells effectively reduced the extent of injury to the adjacent corneal tissue. They accelerated the epithelial layer repair, reduced the inflammatory response and neovascularization, and improved the disorganization of collagen and fibronectin in the corneal stroma caused by the injury. In conclusion, xenografted human umbilical mesenchymal stem cells can survive in rat eye tissues for a long time, effectively support the structural integrity of injured corneal tissues, restore corneal permeability, and reduce abnormal neovascularization. This study provides a new approach to the treatment of photokeratitis.