Targeted Corneal Sensory Nerve Depletion via Subconjunctival Injection: A Model for Investigating Bacterial Adhesion and Neuroimmune Interactions

Corneal sensory nerves play a pivotal role in supporting ocular surface integrity and immune defense mechanisms. Loss of this innervation has been associated with increased vulnerability to microbial invasion, yet the precise contribution of nerve depletion to bacterial adhesion on the cornea remains insufficiently characterized. Here, we present a reproducible and temporally controlled method for selective corneal sensory nerve suppression using bupivacaine, a long-acting sodium channel blocker. By combining subconjunctival and topical delivery routes, this dual-application strategy achieves robust, sustained denervation, allowing for precise investigation of how altered sensory input influences corneal epithelial susceptibility to bacterial colonization. Using this model, we investigate how sensory denervation influences microbial adhesion dynamics for Staphylococcus aureus, Staphylococcus epidermidis, and Pseudomonas aeruginosa three clinically relevant pathogens with distinct adhesion mechanisms. Standardized bacterial inoculation via the laboratory wipe blotting method ensures uniform deposition on the corneal surface, followed by quantitative assessment of bacterial adhesion. Bupivacaine-induced nerve depletion correlates with reduced corneal nerve density and increased bacterial adhesion, confirming a functional link between sensory depletion and microbial susceptibility. By simulating neuropathic conditions such as diabetic neuropathy and neurotrophic keratitis, this approach provides a novel framework for studying neuroimmune interactions in ocular infections. Beyond infection models, this subconjunctival injection strategy offers a versatile platform for investigating ocular drug pharmacokinetics, neuroprotective interventions, and immune modulation. Furthermore, it can be adapted for gene modification studies, including subconjunctival delivery of CRISPR/Cas constructs or viral vectors, broadening its applications in ophthalmic research and therapeutics.