Calcitriol, the Active Metabolite of Vitamin D₃, Inhibits Dry Eye Related Corneal Inflammation In Vivo and In Vitro

ABSTRACT

Purpose: To examine the influence of topical administration of calcitriol on dry eye (DE) related corneal inflammation.

Methods: Benzalkonium chloride (BAC, 0.2%) was applied to induce DE. Then rats were treated topically with calcitriol (10⁻⁶μM). Tear break-up time (TBUT), fluorescein staining score, inflammatory index, and tear volume were measured. Corneal epithelium damage and corneal inflammation were examined by H&E staining or RT-qPCR. In vitro, human corneal epithelial cells (iHCEC) were cultured in hyperosmotic medium (450 mOsM) with various concentrations of calcitriol. Levels of pro-inflammatory mediators were measured by RT-qPCR or ELISA. NF-κB activation was examined by Western blotting and immunofluorescence staining.

Results: Calcitriol significantly ameliorated DE symptoms, attenuating corneal inflammation. In vitro studies showed that calcitriol significantly decreased the expression of pro-inflammatory mediators in iHCECs under hyperosmotic stress, probably through inhibiting NF-κB activation.

Conclusion: The results suggest that calcitriol might be a potential therapeutic agent for DE.

Keywords:

• Calcitriol
• corneal inflammation
• DE
• vitamin D₃

DECLARATION OF INTERESTS

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

FUNDING

This work was supported by the Natural Science Foundation of Shanghai [17ZR1404400], the National Natural Science Foundation of China [81670820,81170817], New Technology Joint Research Project in Shanghai Hospitals [SHDC12014114]. The sponsor or funding organization had no role in the design or conduct of this research.

Additional information

Funding

This work was supported by the Natural Science Foundation of Shanghai [17ZR1404400], the National Natural Science Foundation of China [81670820,81170817], New Technology Joint Research Project in Shanghai Hospitals [SHDC12014114]. The sponsor or funding organization had no role in the design or conduct of this research.