Efficacy of rhNGF-loaded amniotic membrane transplantation for rabbit corneal epithelial and nerve regeneration

AIM:To evaluate the efficacy of recombinant human nerve growth factor-loaded amniotic membrane(rh NGF-AM)on corneal epithelial and nerve regeneration in rabbit model.METHODS:Freshly prepared human amniotic membrane(AM)were immersed into PBS buffer containing 100 or 500μg/mL rh NGF for 15,30,and 60 min at 4℃.The in vitro release kinetics of rh NGF was measured with ELISA.For in vivo evaluation,the AM were immersed with 500μg/mL rh NGF for 30 min.Fifty-seven rabbits were selected to establish corneal epithelial defect model.In addition to the 19 rabbits in control group,38 rabbits received AM transplantation with or without rh NGF after the removal of central epithelium.Corneal epithelial defect area,sub-epithelial nerve fiber density,corneal sensitivity,rh NGF contents in resident AM and corneas were measured after the surgery.RESULTS:rh NGF was sustained release from the AM within 14 d in vitro,with the positive correlation with initial immersion concentration.The immersion of AM in 500μg/mL rh NGF for 30 min achieved the most stable release within 14 d.After transplantation in rabbit cornea,a high concentration of rh NGF in resident rh NGF-AM and cornea was maintained within 8 d.Corneal epithelial healing,nerve fiber regeneration and the recovery of corneal sensitivity were significantly accelerated after the rh NGF-AM transplantation when compared to simple AM transplantation(all P<0.05).CONCLUSION:Simple immersion of AM achieves the sustained release of rh NGF,and promotes corneal epithelial wound healing and nerve regeneration,as well as the recovery of corneal sensitivity in rabbit.