Therapeutic efficacy of different routes of mesenchymal stem cell administration in corneal injury

Abstract

Purpose : Corneal injuries are associated with significant impairment in vision. Our previous work has shown that mesenchymal stem cells (MSCs) promote tissue repair and restore corneal transparency following injury. Here, we aim to evaluate the efficacies of local and systemic routes of MSC administration in suppressing corneal opacity and inflammation, while promoting tissue repair in a murine model of corneal injury.

Methods : MSCs were purified from the bone marrow of C57BL/6J mice and expanded using plastic adherence in vitro. Corneal injury was created by removal of the corneal epithelium and anterior stroma using Algerbrush and 0.5x10⁶ MSCs were administered in mice through topical, subconjunctival, intraperitoneal and intravenous routes. Corneal opacity was evaluated using slit-lamp biomicroscopy; bright-field images were analyzed by ImageJ software and opacity was quantified as percentage of the total corneal area. Corneal fibrosis was evaluated by quantifying the mRNA expression of α-smooth muscle actin (α-SMA) through real-time PCR. Infiltration of CD45⁺ cells was evaluated using flow cytometry. Corneal structure was examined by hematoxylin and eosin staining of the cross sections of whole eyeball.

Results : Injury-induced corneal opacity was significantly reduced in mice receiving subconjunctival (13.96±3.41%, p=0.039) and intravenous (17.15±8.79%, p=0.041) MSCs, compared to untreated injured mice (51.97±10.05%). No significant reduction in corneal opacity was detected in mice receiving topical (41.07±6.13%) and intraperitoneal (36.79±9.97%) MSCs. Similarly, corneal expression of α-SMA was significantly reduced in subconjunctival (~90%, p=0.024) and intravenous (~78%, p=0.021) routes of MSC administration compared to untreated injured mice. Corneal infiltration of CD45⁺ cells was significantly reduced in subconjunctival (1.46±0.34%, p=0.042) and intravenous (1.51±0.4%, p=0.044) routes of MSC administration, but not in topical (3.08±0.28%, p=0.062) and intraperitoneal (3.58±0.18%, p=0.535) routes, compared to untreated group (5.09±0.24%). MSC treatment via subconjunctival and intravenous routes normalized corneal tissue structure to a greater extent than topical and intraperitoneal routes.

Conclusions : Our data suggest that subconjunctival and intravenous routes of MSC administration are the most effective in suppressing corneal opacity and inflammation, and promoting tissue repair.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.