A new rhinitis model using chemical mediators in rats.

Area of Science:

• Otorhinolaryngology
• Pharmacology
• Animal Models

Background:

• Existing experimental models for rhinitis are inadequate for studying nasal congestion.
• A quantitative model is needed to assess rhinitis symptoms and nasal mucosal changes.

Purpose of the Study:

• To develop a novel experimental model for rhinitis in rats.
• To establish quantitative indices for nasal congestion and nasal mucosal capillary permeability.

Main Methods:

• Male Wistar rats were used, with nasal cavities ventilated via cannulae and connected to an artificial respirator.
• Intranasal resistance was measured as ventilation overflow (VO) using a modified Konzett-Rössler apparatus.
• Rhinitis was induced by intranasal inhalation of chemical mediators (histamine, bradykinin, acetylcholine, serotonin), and capillary permeability was assessed using Evans blue dye.

Main Results:

• Inhalation of histamine, bradykinin, and acetylcholine (at 0.3%) significantly increased ventilation overflow, indicating nasal congestion.
• Serotonin inhalation did not affect ventilation overflow.
• Histamine, bradykinin, and high-concentration acetylcholine significantly increased Evans blue dye exudation, signifying increased nasal mucosal capillary permeability.
• Serotonin did not increase capillary permeability.

Conclusions:

• A new rhinitis model was successfully established, allowing for quantitative determination of nasal blockage and increased nasal mucosal capillary permeability.
• Histamine and bradykinin inhalation can induce rhinitis-like symptoms in this model.
• Serotonin does not appear to induce rhinitis-like symptoms in this experimental setup.