Dexamethasone alleviates allergic asthma immature rat through Toll like receptor 4.

OBJECTIVE: The allergic asthma model induced by ovalbumin (OVA) was established in the immature rat. Dexamethasone (DXM) was adopted for intervention to analyze the treatment effect and to explore the relationship with toll-like receptor 4 (TLR4).

MATERIALS AND METHODS: Immature SD rat was treated by OVA to construct allergic asthma model and intervened by DXM. The rats were randomly divided into model group, experimental group, and control group. The changes in lung tissue were observed by light microscope. The EOS infiltration and reactivity of airway wall were compared. The expressions of TLR2 and TLR4 protein and mRNA in the lung tissue were tested by Western blot and RT-PCR.

RESULTS: The lung tissue in the model group was infiltrated by a lot of inflammatory cells, and mucous membrane edema was observed, compared with that in the control group. There were only a few inflammatory cells in the interstitial tissue and pulmonary alveoli in the experimental group compared with that in the model group. EOS count of airway wall and airway reactivity decreased in the experimental group. The levels of TLR2 and TLR4 were significantly elevated in the third week compared with the first week (p<0.05).

CONCLUSIONS: The treatment of DXM can alleviate the pathological changes of the lung tissue in SD immature rat with allergic asthma, reduce EOS infiltration in the airway wall, decrease airway reactivity, and elevate expressions of TLR2 and TLR4.