Changes of interleukin-6 in pulmonary hypertension mice induced by chronic hypoxic-hypercapnia

AIM: To investigated the changes of interleukin-6 (IL-6) in the pulmonary hypertension mice induced by chronic hypoxic hypercapnia. METHODS: Sixteen male C57BL/6 mice were randomly divided into 2 groups (8 mice in each group): normal control group and chronic hypoxic hypercapnia group. The mice in chronic hypoxic hypercapnia group were placed in a sealed chamber where O₂ concentration was kept at 9%~11%, and the CO₂ concentration at 5% ~6%, 8 h a day, 6 days a week for 4 weeks. The right ventricular (RV) weight, the weight of left ventricle plus ventricular septum (LV+S) were measured and right ventricular hypertrophy index was calculated. The structural changes of the pulmonary arteries were assessed by the method of histology with HE staining. The vessel wall diameter/total diameter (WT%) and the vessel wall area/total area (WA%) were analyzed by Image-Pro Plus 6.0 software. The protein expression of IL-6 in the lungs of the mice was determined by immunohistochemistry and ELISA, and the mRNA expression of IL-6 in the lungs was determined by RT-PCR. RESULTS: Compared with control group, RV/(LV+S), MT%, MA% and the expression of IL-6 at mRNA and protein levels were significantly increased in chronic hypoxic hypercapnia group. CONCLUSION: In the environment of chronic hypoxia and hypercapnia, the expression of interleukin-6 was elevated in mouse lungs, which may closely related to the development of pulmonary hypertension.