Abstract
Purpose: :
To develop a novel and highly efficient mouse model for neurotrophic keratopathy by approaching the trigeminal nerve from the lateral fornix.
Methods: :
Six- to 8-week-old adult BALB/c mice underwent trigeminal axotomy to destroy the ophthalmic branch of the trigeminal nerve. Following small incision lateral canthotomy, the globe was rotated nasally by gently pushing the nasal fornix with blunt forceps, exposing the trigeminal nerve and minimizing intraoperative bleeding through mild elevation of the intraorbital pressure. After rotation of the globe, the ophthalmic branches of the trigeminal nerve were cut at the posterior sclera around optic nerve with sharp forceps under the direct observation. Normal and axotomized corneas were excised on post-operative days 1, 3 and 5, and immunofluorescence histochemistry performed with anti-β-tubulin antibody to evaluate subbasal and stromal nerve densities.
Results: :
The survival rate was 100% with minimal bleeding during and following axotomy. The procedure was highly reproducible with a duration of 10 minutes or less. The nerve densities of the subbasal plexus decreased from 71.3±8.4 (central) and 58.8±5.4 mm/mm2 (peripheral) in normal cornea, to 37.9±8.8 (central) and 54.9 ±15.4 mm/mm2 (peripheral) in the axotomized cornea at day 1 (p<0.001). The subbasal nerve plexus could not be detected after day 1 after axotomy. The nerve density of the normal central stroma was 18.8±5.2 mm/mm2 and decreased to 15.0±4.0, 6.2±0.6 and 5.1±1.5 mm/mm2 in the axotomized cornea at days 1, 3 and 5, respectively (p=0.028). The nerve density of the peripheral stroma decreased from 20.5±5.0 mm/mm2 in the normal cornea, to 16.1±2.8, 7.1±1.3, and 3.4±1.6 mm/mm2 in the axotomized cornea at day 1, 3 and 5, respectively (p=0.001).
Conclusions: :
Compared to previously reported models, our trigeminal axotomy mouse model is highly effective, easy, fast, less invasive, and has a superior survival rate. This model will enable us to investigate the effects of corneal nerve damage and serves as a unique model for neurotrophic keratopathy.
Keywords: nerve fiber layer • cornea: stroma and keratocytes • microscopy: light/fluorescence/immunohistochemistry