Coincidental increase of leukotriene B4 between cerebral cortex and lung tissue of sensitized rats.

AIM: To explore the changes of leukotrienes (LT) in cerebral cortex and lung tissues in ovalbumin-induced rat asthma model and effects of different anti-asthma drugs on the changes.

METHODS

Aerosol antigen-induced changes of inflammation in bronchoalveolar lavage fluids (BALF), pulmonary and brain histologic section in sensitized rats were investigated. Changes of LTB4 and LTC4 in lung and cerebral cortex homogenates were analyzed by reverse-phase high performance liquid chromatography (RP-HPLC).

RESULTS

The number of inflammatory cells in BALF and the score of lung and brain histological examination from antigen- challenged rats were significantly higher than that from control group (P<0.05). Dexamethason (DXM, 0.5 mg/kg, ip) and ketotifen fumarate (KF, 5 mg/kg, ig) markedly reduced total leukocyte number in BALF, and inhibited eosinophil accumulation, reduced the infiltration of eosinophils, and improved mucous edema and epithelial lesion of bronchi and bronchioles. In addition, RP-HPLC results shown LTB4 in lung and cerebral cortex homogenates were increased in antigen-challenged rats [(4.1+/-2.4) ng/g and (1.5+/-0.9) ng/g, respectively] compared with control group [(1.55+/-0.21) ng/g and (0.7+/-0.3) ng/g, respectively, P<0.05], both DXM (0.5 mg/kg, ip) and KF (5 mg/kg, ig) reduced LTB4 amount in lung[(1.4+/-0.6) ng/g and (1.8+/-0.7) ng/g] and cerebral cortex homogenates [(0.5+/-0.4) ng/g and (0.7+/-0.4) ng/g] in asthma rats. LTC4 content in lung homogenates in asthma rats was increased compared with control group [(1.9+/-0.9) ng/g and (0.5+/-0.3) ng/g, respectively] (P<0.05), but it has no change in cerebral cortex homogenates. DXM (0.5 mg/kg, ip) and KF (5 mg/kg, ig) reduced LTC4 amount in lung homogenates in asthma rats [(0.8+/-0.6) ng/g and (1.0+/-0.3) ng/g, respectively] (P<0.05).

CONCLUSION

The results indicate there is coincidental increase of LTB4 between central nervous system and lung tissues in asthma rats. DXM and KF can inhibit the change.