Tibialis anterior muscles (TA) were fixed in 10% formalin for 24 h and embedded in paraffin. Immunohistochemistry was carried out as previously described (2 (link)) using antibodies directed against cluster of differentiation 68 (CD68), 4-hydroxy-2-nonenal (HNE), interleukin 1-beta detecting mature and precursor form (IL-1β), interleukin 18 detecting only mature form (IL-18), peroxiredoxin 3 (PRDX3), and tumor necrosis factor alpha (TNFα) (Supplementary Information, Table S1). Whole muscle sections were scanned, and then the optical density of diaminobenzidine (DAB, ThermoFisher-Scientific, Waltham, MA, USA) deposits (IL‐1β, TNFα, HNE and PRDX3) or the percentage of stained areas (IL-18, CD68) was quantified using Fiji (NIH, Maryland, USA). TA sections were also stained with haematoxylin and eosin. In addition, Quadriceps (Q) sections (described below) were stained with Picro-Sirius red (Abcam, Cambridge, UK) to evaluate muscle fibrosis. Fibrotic tissue was scored setting a color balance threshold and data obtained were expressed as the percentage of total section area.
Free full text: Click here