T helper sub-types imbalance is intricate in type 1 diabetes (T1D) and asthma initiation. Quercetins role on immune dysregulation in comorbid conditions of T1D and asthma is not available. In this study, it was thought worthy to evaluate the role of quercetin on modulating Th1/Th2 cytokine dysregulation in comorbid diabetic asthma. Male Balb/c mice were injected intravenously with alloxan (80 mg/kg) to persuade T1D. Succeeding diabetes introduction, two intraperitoneal sensitizing doses of ovalbumin emulsion (50 µg ovalbumin blended with 2.5 mg alum/sensitization) were given on days 3 and 8. Mice were given intranasal challenges of ovalbumin (100 µg ovalbumin/25 µl of sterile saline) on days 13-15. Oral quercetin treatment (10 & 30 mg/kg) was given daily on days 3-15. Nasal hyperresponsiveness (NHR) was recorded immediately after Ova challenge on day 16. Bronchioalveolar lavage fluid (BALF), blood and lungs were collected 1 h post NHR for further analysis. Quercetin treatment significantly decreased eosinophils, interleukin-4 while increasing interferon-gama in blood, BALF and reduced allergic airway inflammation by inhibiting inflammatory cells infiltration and mucus cell metaplasia. Further, quercetin 30 mg/kg demonstrated significant glucose reduction. Thus, quercetin exerted dose dependent anti-asthma activity by modulating Th1/Th2 balance with glucose lowering potential in comorbid mice.
Key words: Quercetin; Th1/Th2 balance; Ovalbumin; Comorbid diabetic asthma; Allergic inflammation