2.4 Hydroxyproline assay
To estimate the collagen synthesis in the lungs, we measured the amount
of hydroxyproline via ELISA analysis (Shanghai Yubo Biological
Technology). Briefly, lung tissues were homogenized in 1 ml
phosphate-buffered saline (PBS) and centrifuged at 4000 rpm for 15 min.
The supernatant was collected and BCA measurement was performed to
examine the total amount of proteins in lung tissues. Hydroxyproline
content was measured according to the Manufacturer’s instructions and
determined by a colorimetric assay using a spectrophotometer at a
wavelength of 450 nm. Data were present as µg hydroxyproline /µg of lung
tissue.