Lectin histochemical staining profiles in sections of OA cartilage. (a) Binding of PNA to complex chondrons of a severely degenerated cartilage region could be completely blocked with lactose (inset) ascertaining carbohydrate-specific binding. (b) Omission of the incubation step with biotinylated LEA (first-step reagent) from processing excluded probe-independent signal generation. (c, d) ConA staining: staining pattern of MS ≤4 regions included chondrocytes in deep zones of cartilage (c). Intense staining of matrix and chondrons (inset) in MS ≥9 regions (d). (e) PSA staining: positivity of chondrons (inset) and matrix, predominantly in MS ≥9 cartilage. (f, g) PHA-E staining: whereas MS ≤4 regions were negative (f), MS ≥9 areas (g) presented positive chondrons (inset) and matrix. (h) PHA-L staining: binding sites were restricted to chondrons (insert) and matrix of MS ≥9 cartilage. (i-j) VAA staining: whereas the chondrons of MS ≤4 areas were negative (i), reactivity was observed both in chondrons (inset) and matrix of MS ≥9 cartilage (j). (k) LEA staining: reactivity for chondrons (inset) and matrix of MS ≥9 regions. (l) MAA-I staining: reactivity included chondrons (inset) and matrix of MS ≥9 cartilage. (m, n) SNA staining: weak staining of matrix and no staining of chondrons in MS ≤4 cartilage (m), whereas both chondrons (inset) and matrix were positive in MS ≥9 regions (n). (o) DBA staining: positivity in chondrons (inset) and matrix of MS ≥9 cartilage. (p, q) PNA staining: positive chondrocytes sparely distributed in the deeper zones of MS ≤4 cartilage (p; arrows, inset). In MS ≥9 cartilage (q), intense matrix staining was observed, whereas chondrons were mostly negative (inset). (r) JAC staining: absent in chondrons (inset), but present in superficial zones of MS ≥9 cartilage. Bars in inserts of d,e,g,l,n,p,q,r: 50μm. Bars in inserts of h,j,k,o: 100μm. MS, Mankin score; OA, osteoarthritis.
Toegel et al. Arthritis Research & Therapy 2013 15:R147 doi:10.1186/ar4330