Topical Epigallocatechin-3-gallate hydrogels regulated inflammation and pain

The aim of this study is to determine in vivo response of topical Epigallocatechin-3-gallate (EGCG) hydrogels to pain and inflammation through Toll-like receptor 4 (TLR4), Superoxide dismutase (SOD1), Prostaglandin E2 (PG-E2) and Transient receptor potential vanilloid 1 (TRPV1) in pulpal inflammation. Rats (n=35) were divided into a normal group (N), a positive control group induced with LPS for 6 hours (C1), a group induced with LPS for 24 hours (C2), a treatment group induced with LPS and topical EGCG 120 μg/ml (T1) for 6 hours and a group induced with LPS and topical EGCG 120 μg/ml for 24 hours (T2). Tissues were collected and observed by means of immunohistochemistry (IHC) to detect the expression of TLR4, SOD1, PG-E2 and TRPV1. Data were analyzed using a One-Way ANOVA test for TLR4, PG-E2 and TRPV1, while SOD1 was analyzed using a Brown-Forsythe test and Games Howell test. Application of topical 120 μg/ml EGCG hydrogels in tooth cavities at 6 hours and 24 hours pulpal inflammation significantly increased the expression of SOD1, while significantly decreasing the expressions of TLR4, PG-E2 and TRPV1 (P < 0.001). EGCG can be used as a pain inhibitor, anti-inflammatory agent and antioxidant agent against pulpal inflammation in rat models.