OBJECTIVETo observe the expression of Clara cell secretory protein(CCSP) in the Kunming mouse model of n-hexane long-term inhalation, and to discuss the functions of Clara cell in injury lung induced by n-hexane.

METHODS24 healthy mice were randomly divided into 4 groups: one control group and three n-hexane groups (4 w, 8 w and 12 w), 6 each group. Primary concentration of n-hexane was 17.6 g/m3, 8 hours per day, 6 d per week. After inhalation, n-hexane concentration of blood from celiac artery was detected. The lungs were embedded with paraffin and HE staining in the routine. The ratio of Clara cells with CCSP reaction in bronchiole and the number of macrophage cells with lysozyme reaction were determined by immuno-histochemistry.

RESULTSIn the poisoning groups, the average n-hexane concentration of blood was significantly higher than that of the control group (P < 0.01). There were apparent pathologic damages in lungs of the poisoning mice. In poisoning 4 w, 8 w and 12 w groups, the ratio of Clara cells was significantly decreased [(73.33 +/- 4.21)%, (60.98 +/- 4.94)%, (34.04 +/- 2.33)% in terminal bronchiole, and (75.44 +/- 7.91)%, (58.54 +/- 4.86)%, (33.35 +/- 2.67)% in respiratory bronchiole] as compared with the control mice [(80.26 +/- 6.43)% and (81.74 +/- 7.75)%, P < 0.05 or P < 0.01], meanwhile the numbers of macrophage cells were gradually increased [(21.39 +/- 7.41), (28.54 +/- 10.73), (48.97 +/- 19.55) per microscopic field at 200x] in poisoning mice than those in control mice [(7.84 +/- 3.12) per microscopic field at 200x, P < 0.05 or P < 0.01].

CONCLUSIONIn injury lungs after n-hexane inhalation, Clara cells are the target cells of n-hexane toxicity effect. Clara cells play an extensive protective role in lung inflammation.