Fig. 1.

MA induced chronic lung injury. a MA-induced chronic lung injury by H&E staining (Olympus BX 51, Japan, × 200 and × 400). Long-term exposure to MA caused more compact lung parenchyma, the thickened alveolar septum, and the reduced number of alveolar sacs. b The thickness of the alveolar septum. c The number of alveolar sacs. d Percentage of weight gain of rats in the Con and MA groups (n = 9). e Percentage of right heart index gain of rats in the CON and MA groups (n = 9). The quantification of b and c was 11analyzed in 3 visual fields randomly selected in a section (n = 3), respectively. Data are presented as the mean ± SD. *P < 0.05, **P < 0.01 vs. CON. CON, control; MA, methamphetamine