Bicalutamide, an androgen receptor antagonist, effectively alleviate allergic rhinitis via suppression of PI3K-PKB activity.

ABSTRACT

OBJECTIVES: To investigate the therapeutic effect of Bicalutamide, an androgen receptor antagonist on the onset and development of allergic rhinitis in an animal model. METHODS: 40 male BALB/c mice were randomly divided into five groups (eight mice per group). Aluminum hydroxide powder was used as an adjuvant, combined with Ovalbumin (OVA) to establish the mouse model of allergic rhinitis via ultrasonic nebulization of OVA to stimulate the nasal cavity. Mice in Bica#1 group were intraperitoneally injected with 0.02 mg Bicalutamide/0.5 ml of normal saline daily for 7 consecutive days; mice in Bica#2 group were administered 0.02 mg Bicalutamide/0.5 ml of normal saline via intraperitoneal injection for 5 consecutive days, and then the same amount of normal saline was injected intraperitoneally for 2 consecutive days. Enzyme-linked immunosorbent assay was adopted to detect the serological levels of IgE, IL-4, and IL-6 production. Eosinophil infiltration was observed under microscope after hematoxylin and eosin staining of nasal mucosa. Quantitative PCR and Western blot were employed for determination of histamine receptors mRNA expression and PI3K/PKB associated protein levels, respectively. RESULTS: Histological analysis shown that allergic lesion was induced after OVA sensitization. Intraperitoneal injection with 0.02 mg Bicalutamide daily for 7 consecutive days significantly reduced the allergic lesion; however, mice injected with the same amount of normal saline at the same time demonstrated no allergic rhinitis symptoms. In addition, there was a significant reduction in eosinophils number in Bicalutamide treated mice (n = 8) compared to the OVA group (n = 8) (OVA 19.6 ± 5.3 vs. Bica#1 7.7 ± 0.8 vs. Bica#2 9.4 ± 1.2, both p < 0.01). Furthermore, ELISA results revealed that the serological levels of IgE (OVA 17.3 ± 1.7 µg/ml vs. Bica#1 9.2 ± 0.6 vs. Bica#2 10.4 ± 2.3, both p < 0.05), IL-4 (OVA 164.3 ± 5.1 pg/ml vs. Bica#1 110.2 ± 3.1 vs. Bica#2 115.3 ± 4.1, both p < 0.05) and IL-6 (OVA 167.3 ± 3.7 pg/ml vs. Bica#1 117.5 ± 6.5 vs. Bica#2 114.8 ± 2.4, both p < 0.05) were significantly decreased after two different dosage of Bicalutamide treatment. Similarly, histamine receptors in mast cells were significantly reduced after two different dosage of Bicalutamide treatment. More importantly, p-PKB protein was notably reduced after two different dosage of Bicalutamide treatment compared to the OVA group, mTOR protein levels were also down regulated after two different dosage of Bicalutamide treatment. CONCLUSIONS: Our data demonstrated that androgen receptor antagonist Bicalutamide can significantly alleviate allergic rhinitis lesion in the animal model. PI3K/PKB activity in mast cells was suppressed after Bicalutamide injection. Our results provide important implication in allergic rhinitis prevention and treatment.