OBJECTIVETo determine the changes in the expression of leptin and its receptor in the lungs of mice with varying degrees of asthma before and after budesonide treatment.

METHODSForty Balb/c mice were randomly assigned into 4 groups with 10 animals in each. One group received no treatment (control group) and the other groups were challenged with either nebulized ovalbumin (OVA) for three days (3-day group) or seven days (7-day group), or with nebulized ovalbumin followed by budesonide administration (treatment group). Changes in airway inflammation were observed using hematoxylin-eosin staining. The protein and mRNA levels of leptin and its receptor in lung tissues were determined using immunohistochemistry/Western blot and real-time PCR, respectively.

RESULTSThe two asthmatic groups showed more significant pathological changes in the airway than the control and the treatment groups. Mice that were challenged by OVA for seven days showed more marked pathological changes in the airway compared with mice challenged by OVA for three days. The protein and mRNA levels of leptin in the lung tissues of the 3-day group were significantly higher than those of the control group (P<0.01), but significantly lower than those of the 7-day group (P<0.01). The protein levels of leptin receptor in the lung tissues of the 3-day group were significantly lower than those of the control group (P<0.01). The treatment group showed increased protein levels of leptin receptor compared with the 7-day group (P<0.01). No significant difference was noted between the four groups with respect to the mRNA levels of leptin receptor in the lung tissues.

CONCLUSIONSLeptin is highly expressed whereas its receptor is lowly expressed in the lung tissues of asthmatic mice. Budesonide can increase the expression of leptin receptor, but has no significant impact on the expression of leptin.