Fig. 1.

Experimental design of the study. Seventy C57BL/6J mice were randomly divided into two treatment groups (n=35 for each group). (A) Group I: mice were instilled intratracheally with B(a)p (1 mg/mouse) and lipopolysaccharide (LPS) (5 µg/mouse), once a week for 4 times, on Tuesday and Friday, respectively. At Week 4, mice continued to be treated with LPS, once every four weeks for 5 times. (B) Group II: mice were exposed to B(a)p (1 mg/mouse, once a week for 4 times) and 3 weeks later instilled intratracheally with LPS (2.5 µg/mouse) once every three weeks for 5 times. Thirty weeks after the week of the last dose of B(a)p, mice were anaesthesia by pentobarbital sodium.