A Study Of Interleukin Cytokines In The Neurotrophic Keratitis And Keratoconjunctivitis Sicca Animal Model

Abstract

Purpose: : To observe the concentration of various inflammatory proteins produced by induced symptoms of neurotrophic keratitis using cytokine analysis of collected tear samples. This information is used to aid in the development of an accurate and consistently reproducible model that exhibits symptoms of neurotrophic keratitis and keratoconjunctivitis sicca.

Methods: : Using radiofrequency ablation, the left trigeminal nerve was ablated at the V1-V2 junction to induce conditions of neurotrophic keratitis in the left eye. The symptoms of neurotrophic keratitis and keratoconjunctivitis sicca were isolated in the left eye, while the right eye served as the control in the experiment. Tear samples were collected using capillary tubes after 2 mL of an assay buffer solution was administered to both the experimental and control eyes one day before radiofrequency ablation surgery and three days after. The tears were then stored in a test tube containing 8 mL of the same buffer solution at -70 degrees C, blinded with a randomized code, and sent to an outside laboratory for cytokine analysis.

Results: : Analysis of the tear collection data shows a significant increase in the concentration of Interleukin-1a (IL-1a), Interleukin-1b (IL-1b), and Interleukin-6 (IL-6) present in the experimental (left) eye in comparison to the control (right) eye three days after surgery. This family of proteins has been found to regulate inflammatory responses, which is a strong indicator that neurotrophic keratitis symptoms have been achieved. To confirm these results, a T-test of statistical significance was performed to compare the protein concentrations of IL-1a, IL-1b, and IL-6 in the experimental and control eyes three days after surgery, yielding statistically significant p-values of 0.0108, 0.0140, and 0.0010, respectively.

Conclusions: : The results from the cytokine protein analysis of collected tears suggest that there is a significant increase in pro-inflammatory proteins in the experimental eye after treatment. Inflammation is one of many consequences associated with neurotrophic keratitis and keratoconjunctivitis sicca. This increase in protein concentration implies that radiofrequency ablation of the trigeminal nerve at the V1-V2 junction is a viable option for creating a model that exhibits symptoms of neurotrophic keratitis and keratoconjunctivitis sicca.

Keywords: cytokines/chemokines • inflammation