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Figure 3. Light micrographs of 10-µm-thick serial sagittal sections of the posterior portion that faces the upper compartment of synovitis-induced rat TMJs (synov-TMJ), with ISNT (a,b) or TUNEL (c,d) staining for DNA strand breaks. The sections were pre-treated without proteinase K (PK-) (a,c), or with PK (PK+) (b,d). (a) In the section without PK treatment, there is no reactivity for ISNT in the G1 (grade 1, synovial lining 4–6 layers thick) synovitis of the synovitis-induced TMJ. F: synovial fold. V: blood vessel. Inset: higher magnification of the area indicated by arrowheads in Fig. 3a. The nuclei (N) of the multilayered synovial lining cells are negative for ISNT. (b) In the sections that were treated with PK, ISNT-positivity is found in the synovial lining cells of synovitis-induced TMJs with G1 grade synovitis, and in the fibroblasts of the subsynovial layer. Inset: higher magnification of the area indicated by arrowheads in Fig. 3b. Strong reactivity for ISNT is observed in the nuclei of the multilayered synovial lining cells. (c,d) In the sections without PK (c) or with PK (d) treatment, the synovial lining cells of synovitis-induced TMJs with G1 synovitis are negative for TUNEL. Insets: higher magnification of the areas indicated by arrowheads in Figs. 3c and 3d. There is no TUNEL reactivity in the nuclei of the multilayered synovial lining cells. Eosin staining. Original magnification: x800 and x1600 (inset). Bar = 50 µm.
