Evaluating Allergic Rhinitis Treatments in Rats

All procedures followed ethical standards set by the responsible committee on animal experimentation (institutional and national). Our institution (Bagcilar Training and Research Hospital) has granted ethics committee approval with protocol number 2016/145. This research was conducted on 28 healthy, 2–4 months old Wistar Hannover rats weighing 250–350 g. The rats were divided into four groups: Group 1 (control group), Group 2 (allergic rhinitis model without any treatment), Group 3 (allergic rhinitis model treated with montelukast), and Group 4 (allergic rhinitis model treated with omega-3 fatty acid). All animals were kept at 22 °C room temperature for 12 -hs in a dark/light cycle and fed with standard food daily (Table 1).Table 1

Description and Number of animals in groups.

Table 1

Experimental Groups	Number of animals
Group 1 Control Group	7
Group 2 Allergic Rhinitis Control Group	7
Group 3 AR Group given montelukast treatment	7
Group 4 AR Group given omega-3 fatty acid oil	7

AR, Allergic Rhinitis.

The study drugs were prepared via weighing on the Sartorius precision scale (GD603-0CE Carat Scale, Sartorius Mechatronics, Goettingen, Germany). Antigen solution was prepared as 0.3 mg Ovalbumin (OVA, Grade V, Sigma-Aldrich Chemical Co. St. Louis, MO) in 1 mL 0.9% saline and 30 mg aluminum hydroxide intraperitoneally (second, third, and fourth groups). Sensitization was created by applying once every two days for 14 days between 11:00–12:00. In the control group, the animals were intraperitoneally administered 1 mL of 0.9% saline intraperitoneally, once every two days for 14-days between 11:00‒12:00.
In the second stage of the study, to create an AR model in the sensitized animals, 1.0 mg/mL OVA in 0.9% SF and 0.54 U protease from Aspergillus oryzae was centrifuged, and 30 μL of the solution was instilled into both nostrils with a micropipette every day for 15 days. Alongside to the OVA + protease application, the third group received a 10 µL montelukast solution one hour before OVA application for 15 days via gavage. The rats in the fourth group were fed a mixture containing 8% omega-3 fatty acid. Ten microL 0.9% saline was applied to both nostrils of the animals in the control group for 14 days. Omega-3 and montelukast were initialized from the fifteenth study day and continued daily. Twenty-four hours after the drug application, all animals were sacrificed.
Subjective evaluation of allergic rhinitis symptoms was performed on days 1, 14, 17, 20, 23, 26, and 28 following intranasal OVA application after a 10-minute adaptation period with one animal in each cage. Nose scratching and sneezing were evaluated by the same physician.