LAUSR

BACKGROUND The X-rays and the visible light are the main source of ultraviolet radiation (UVR). About 90% of ultraviolet B (UVB) are absorbed by the cornea which may promote corneal inflammation, oedema and damage of its epithelial layer. Bone marrow mesenchymal stem cells (BM-MSCs) have been demonstrated to ameliorate the injured corneal tissue and accelerate its wound healing. This study aimed to compare the healing effect of intravenous (IV) versus subcutaneous (SC) BM-MSCs on the rats, corneas subjected to UVB-irradiation. MATERIALS AND METHODS Ten rats were used as donors for BM-MSCs and the other 40 were allocated into 4 equal groups. Group I (control group), Group II (ultraviolet irradiated group), Group III (ultraviolet irradiated + IV BM-MSCs treated group) and Group IV (ultraviolet irradiated +SC BM-MSCs treated group). Rats of all groups were euthanized after 3 weeks and the corneal specimens were processed for histopathological, immunohistochemical and electron microscopy assessment. RESULTS ultraviolet irradiated group showed remarkable thinning of epithelial thickness, wide partial epithelial separation, and desquamation. Neovascularization of the disorganized stroma and disrupted Descemet's membrane. The superficial and basal epithelial cells appeared irregular and separated by wide intercellular spaces and inflammatory cells. Immunohistochemical examination showed a significant decrease in PCNA immunoreaction. In contrast, minimal changes were observed in rats treated with BM-MSCs with more improvement associated with the subconjunctival administration compared to intravenous route. CONCLUSIONS Local SC injection of BM-MSCs has an amazing regenerative efficacy on the corneal injury compared to the systemic IV route.