Abstract
Purpose :
To investigate the fate of human umbilical cord mesenchymal stem cells (MSCs) after transplantation in rats and their impact on the corneal limbal niche.
Methods :
MSCs isolated from human umbilical cord were injected in the limbal stroma area of Sprague-Dawley rats. Slit lamp image was taken at different time points post injection. The expression of Vimentin, α-SMA and Ki67 was detected using double immunofluorescence staining. TUNEL assay was performed to evaluate cell apoptosis. CD11b or CD45 positive cells in the limbal stroma were quantified by flow cytometry. The expression of cytokines, collagens, Notch and BMP signaling pathway related genes/proteins were analysed using Real-Time PCR, ELISA or Western blot. Rat models of limbal stem cell deficiency were established to evaluate the therapeutic efficiency of MSCs limbal injection on wound healing. Following up was performed on 3, 6, 9 and 12 days post-injection to evaluate corneal epithelium defect, conjunctival hyperemia and neovascularization.
Results :
Majority of MSCs survived at day 6 after injection, while the cell mass gradually decreased, then disappeared on day 9 post-injection. Immuno-staining against α-SMA was negative from day 3 to day 12. K14 expression in limbal basal epithelium was higher on day 3 to day 6 than control group. TUNEL positive cells were present in the injected cell mass and reduced gradually. Compared with the control eyes, the quantities of CD11b+ and CD45+ cells were increased in the injected eyes, and gradually reduced to normal basal levels on day 12. The mRNA levels of pro-inflammatory and anti-inflammatory factors were both up-regulated. The gene and protein expression of KGF, EGF, SDF-1α, collagen, Notch1, HES-1 and BMP4 increased on day 3 and day 6 post injection. Corneal epithelial wound healing was significantly promoted in the MSC injected rats.
Conclusions :
MSCs survived up to 12 days post-injection and were eliminated gradually. The limbal niche was altered through paracrine function and activation of Notch and BMP signaling pathways thereby promoting corneal epithelial wound healing.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.