Neural Mechanisms of Swallowing Inhibition Following Noxious Orofacial Stimulation

Effects of loxoprofen on impaired water-evoked swallows in a pharyngitis rat model

OBJECTIVE

The objective of this study was to investigate the effects of nonsteroidal anti-inflammatory drugs (NSAIDs; e.g., loxoprofen) on pharyngitis-induced dysphagia in rats.

DESIGN

A pharyngitis rat model was generated by topical application of acetic acid to the laryngopharyngeal region. Changes in water swallowing were evaluated by endoscopic observation over time. A histological analysis of the laryngopharyngeal mucosa was performed. The effects of loxoprofen, antibacterial drugs, and transient receptor potential (TRP) channel inhibitors were investigated in model rats.

RESULTS

After acetic acid treatment, water-evoked swallowing was impaired on day 1 (prolonging the swallowing latency and interval and decreasing the number of swallows), and recovered until day 6. Administration of loxoprofen significantly alleviated impaired water swallowing. Histologically, loxoprofen significantly improved inflammation of the pharynx, including submucosal edema, but did not affect the loss of taste bud-like structures in the arytenoid. In contrast, the administration of antibacterial drugs or TRP channel inhibitors did not affect the impairment of water swallowing in the model group.

CONCLUSION

These results demonstrate the efficacy of systemic administration of loxoprofen in improving swallowing impairment in a pharyngitis model rat. This study is the first to provide scientific evidence for the use of NSAIDs in the management of pharyngitis.