Alterations in the Corneal Nerve and Stem/Progenitor Cells in Diabetes: Preventive Effects of Insulin-Like Growth Factor-1 Treatment
Figure 4
Effect of diabetes and treatment with recombinant human insulin-like growth factor-I (rhIGF-1) on corneal innervation and corneal progenitor/stem cells. Representative histological photomicrographs of corneal nerves that were immunostained with β-III-tubulin showing epithelial nerve (a), the subbasal nerve plexus (b), and stromal nerve trunks. (c) The rhIGF-I administration significantly accelerated recovery of the corneal subbasal nerve and epithelial branches. (d) Histogram of the quantification of the corneal subbasal nerve density. The subbasal nerve plexuses of the diabetic eyes completely diminished compared with that in the normal eyes, whereas those of rhIGF-1-treated diabetic corneas recovered. Statistical comparison of data between groups was performed using the nonparametric Mann-Whitney U test. The bars represent the mean ± SEM (*, **). Representative immunostained micrographs of cross-sections of diabetic and rhIGF-1-treated corneas showing the expression of progenitor/stem cell markers. The decrease in Hes1 (e) and Keratin19 (f) staining was prevented in rhIGF-1-treated diabetic mice compared with diabetic mice (Figures 3(b) and 3(d)).
