Objective: To explore the mechanism of Kechuanluo oral liquid, a compound Chinese herbal medicine, in inhibiting allergic airway inflammation by observing the effects of Kechuanluo on eosinophil (EOS) apoptosis and its regulation factors in asthmatic mice.
Methods: Fifty-six BALB/c mice were randomly divided into normal control group (n=16), untreated group (n=16), Western medicine group (n=12) and Kechuanluo group (n=12). Except for the mice in normal control group, asthma was induced in BALB/c mice by using ovalbumin (OVA) and potassium aluminium sulfate. The mice were intragastrically administered with normal saline, Kechuanluo (30 ml/kg daily) and prednisolone tablets (10 mg/kg daily) respectively for two weeks. At 0 hour, the 3rd, 7th and 14th day after the end of OVA sensitization, the EOSs of lung tissues were counted by improved-Giemsa staining method; immunohistochemical method and image analysis were used to detect the expressions of Fas, FasL and Bcl-XL in the EOSs in the four groups; and apoptotic rates of the EOSs in the lung tissues of asthmatic mice were detected by terminal deoxynucleotidyl transferase-mediated biotin-dUTP nick end labeling (TUNEL) technique.
Results: Compared with the untreated group, airway inflammations of the mice in the Kechualuo group and Western medicine group were lessened and the EOS counts decreased on the 3rd, 7th and 14th day after the last OVA sensitization (P<0.05). On the 3rd day, the EOSs apoptotic rates, the expression areas of Fas in the EOSs and FasL in the lung tissues were significantly higher in the Kechuanluo group than those in the untreated group (P<0.01), furthermore, the EOS apoptotic rate reached the peak level. Inversely, the EOS count and the expression area of Bcl-XL in the EOSs were obviously lower in the Kechuanluo group (P<0.05). On the 7th and 14th day, the expression areas of Fas and Bcl-XL in the EOSs were significantly decreased in the Kechuanluo group (P<0.01), and on the 14th day, the EOS apoptotic rate and the expression area of FasL in the lung tissues were obviously lower either. The effects exhibited in the Western medicine group were similar to those in the Kechuanluo group.
Conclusion: There is airway inflammation with eosinophilic infiltration in asthmatic mice, accompanied with suppressed apoptosis and delayed apoptosis. Kechuanluo can induce and accelerate EOS apoptosis in early inflammation by inhibiting eosinophilic inflammation, improving Fas expression in EOSs and FasL expression in the lung tissues, and reducing Bcl-XL expression in EOSs.