Fig. 1

Body weight changes, pulmonary inflammation, fibrosis, and cough reflex sensitivity in guinea pigs. The cough reflex index was evaluated on the 7th, 14th, 21st, and 28th day after intratracheal administration of bleomycin (n = 16–18 animals/each time point on days 7 and 14; n = 7–8 animals/each time point on days 21 and 28). Samples were collected on the 14th and 28th das after the cough reflex test (a). Body weights of guinea pigs were measured before and after the administration of bleomycin (b). Cough responses to 0.75 μM capsaicin were recorded prior to and on the 7th, 14th, 21st, and 28th day after bleomycin administration (c). On the 14th and 28th day after the intratracheal administration of bleomycin, the lung tissues were collected after animals were sacrificed. The lung tissue sections were stained by H&E (d) and Masson’s stain (e) to evaluate inflammation and fibrosis. Additionally, the concentration of collagen in lung tissues was measured (f). The results of Masson staining were quantified using the Ashcroft scale (n = 6/group/per time point) (g). The data are expressed as the mean ± SD. *P < 0.05