Abstract
Purpose: :
EP4 is one of the four PGE2 receptors and it was reported that EP4 mRNA was present in the intestinal epithelium, and that EP4 maintained intestinal homeostasis and downregulated immune response. Like the intestine, the ocular surface is also one of the mucosa that is in contact with commensal bacteria. We previously reported that human conjunctival epithelium expressed EP4, and that it was down-regulated in the conjunctiva of Stevens-Johnson syndrome/Toxic epidermal necrolysis (SJS/TEN) and cicatricial pemphigoid (OCP) patients. In this study, we examined the expression of EP4 in more various ocular surface diseases.
Methods: :
For immunohistochemistry, we used nearly normal conjunctival tissues obtained during surgery for conjunctivochalasis as a control, and human conjunctival tissues were also prepared from samples obtained during surgeries against Mooren’s Ulcer, giant papillae of chronic allergic keratoconjunctivitis and chemical/thermal eye burn. For EP4 staining, we used the rabbit polyclonal antibody to EP4 (Cayman Chemical Co., Ann Arbor, MI).
Results: :
EP4 protein was detected in the conjunctival epithelium obtained from the patients with conjunctivochalasis, pterygium, Mooren’s Ulcer, giant papillae of chronic allergic keratoconjunctivitis and chemical/thermal eye burn, while EP4 protein was not detected in conjunctival epithelium from patients with SJS/TEN and OCP patients.
Conclusions: :
Our results show that EP4 protein was doen-regulated in conjunctival epithelium from patients with SJS/TEN and OCP patients, but not from patients with pterygium, Mooren’s Ulcer, giant papillae of chronic allergic keratoconjunctivitis and chemical/thermal eye burn.
Keywords: conjunctiva • inflammation • cornea: clinical science