ACTA1 and chronic obstructive pulmonary disease: Masson’s trichrome stain and Immunohistochemistry presented that compared with COPD rats, collagen volume fraction and α-SMA level reduced in COPD rats treated with NAC + oe-NC + sh-NC, and compared with COPD rats treated with NAC + oe-NC + sh-NC, collagen volume fraction and α-SMA level increased in COPD rats treated with NAC + oe-VWF + sh-NC (Fig. 7F, G).