Fig. 1

Immunodetection of NGF receptors in OA articular cartilage. a Immunostaining of the NGF low-affinity receptor, CD271 (or p75NTR), in fetal (n = 3, biological replicates), healthy (normal, n = 3, biological replicates), and OA (early and late stage, n = 5 each, biological replicates) hyaline cartilage from human femoral condyles, showing the superficial zone, middle zone, and deep zone. b Immunostaining of the NGF high-affinity receptor, TrkA, in OA (late stage) hyaline cartilage from human femoral condyles, showing the superficial zone, middle zone, and deep zone. CD271/p75NTR and TrkA presence is revealed by DAB staining (brown). n = 3–5 biological replicates. Negative control, without the use of primary antibody, is at the bottom-left. Bar = 100 μm. Arrows, positive signals of DAB staining. OA osteoarthritis, p75NTR low-affinity NGFR, TrkA high-affinity NGFR