Morphological characterization of intra-articular HMGB1 expression during the course of collagen-induced arthritis

Table 1 Expression of extranuclear HMGB1 compared to those of TNF and IL-1β

		Lining			Sublining			Destructive zone			Cartilage			Vessels
Days p.i.	M.A.I.	HMGB1	TNF	IL-1β	HMGB1	TNF	IL-1β	HMGB1	TNF	IL-1β	HMGB1	TNF	IL-1β	HMGB1	TNF	IL-1β
		1			1			1			1			1
0	0	0	0.5	0.5	0	0	0	-	-	-	1	0	1	0	0	0
3	0	0	0.5	0.5	0	0	0	-	-	-	1	0	1	0	0	0
6	0	0	0.5	0.5	0	0	0	-	-	-	1	0	1	0	0	0
10	0	0.5	0.5	0.5	0.5	0	0	-	-	-	1	0	1	0	0	0
15	3.2 ± 1.8	1	1	1	1	0.5	0	-	-	-	1	0	1	0	0.5	0
21	9.8 ± 3.3	2	4	2	3	3	3	3	3	3	2	0	2	1	3	1
28	11.0 ± 2.3	2	4	2	3	3	3	3	3	3	2	0	2	1	3	1
38	11.8 ± 2.6	2	4	2	3	3	3	3	3	3	2	0	2	1	3	1

The relative frequencies of positively stained cells in the articular tissue were estimated by immunohistochemistry and assigned an expression score on a scale of 0 to 4: 0, negative cells; 0.5, less than 0.5%; 1, 0.5% to 5%; 2, 5% to 20%; 3, 20% to 50%; and 4, more than 50% positively stained cells. For clinical evaluation, a mean arthritis index (M.A.I.) was calculated for the group of four animals studied per time point and expressed as the mean ± standard deviation. The destructive zone did not appear until day 21 p.i. and was defined as synovial tissue adjacent to areas of cartilage and bone destruction. HMGB1, high-mobility group chromosomal box protein 1; IL-1β, interleukin-1-beta; p.i., post-immunization; TNF, tumor necrosis factor.

ISSN: 1478-6362