Tryptophan as a Safe Compound in Topical Ophthalmic Medications: In Vitro and In Vivo Studies

Ocul Immunol Inflamm. 2022 May 19;30(4):940-950. doi: 10.1080/09273948.2020.1856883. Epub 2021 Feb 22.

Abstract

Background: To evaluate the effects of tryptophan (TRP) on normal human corneal and conjunctival epithelium in vitro and the re-epithelization of corneal erosion in rabbits.

Materials and methods: Corneal epithelial cell (10.014 pRSV-T) and conjunctival epithelial cell (HC0597) cultures were used. The cellular metabolism, viability, secretion of IL-1β, IL-6, IL-10, cytoskeleton organization, transwell migration were determined. Cells were incubated in the presence of TRP at 1-100 μM. After corneal de-epithelization rabbits received TRP drops (100 μM), 5 times a day.

Results: TRP increased conjunctival epithelium metabolism at 50 μM and increased the viability of corneal epithelium at 100 μM. TRP (10 μM) enhanced the production of IL-6 by the corneal epithelium and had no effect on IL-1β and IL-10.

Conclusions: TRP had no influence on the cellular cytoskeleton but induced a significant pseudopodia projection in both epithelia. TRP did not influence corneal re-epithelization in vivo. TRP was not toxic for corneal and conjunctival epithelia.

Keywords: Cell culture; Tryptophan; conjunctival epithelium; corneal epithelium; rabbit.

MeSH terms

  • Animals
  • Conjunctiva / metabolism
  • Cornea
  • Epithelium, Corneal*
  • Humans
  • Interleukin-10 / metabolism
  • Interleukin-6 / metabolism
  • Rabbits
  • Tryptophan* / metabolism
  • Tryptophan* / pharmacology

Substances

  • Interleukin-6
  • Interleukin-10
  • Tryptophan