Investigation of MMP-1 genetic polymorphisms and protein expression and their effects on the risk of Kashin-Beck disease in the northwest Chinese Han population

Table 3 Immunohistochemical expression of MMP-1 in different layers of the articular cartilage in the two groups

Articular cartilage	Groups	Level of expression				Positive rate (%)
Articular cartilage	Groups	Negative	+	++	+++	Mean ± SD
Upper layer	Control (n = 21)	0	0	13	8	45.27 ± 20.48
Upper layer	KBD (n = 22)	0	0	3	19	67.02 ± 16.19*
Middle layer	Control (n = 21)	0	9	7	5	35.71 ± 24.80
Middle layer	KBD (n = 22)	0	1	6	15	58.19 ± 18.01*
Deeper layer	Control (n = 21)	6	15	0	0	3.00 ± 32.44
Deeper layer	KBD (n = 22)	0	9	8	5	34.87 ± 27.23*
Total layers	Control (n = 21)	0	12	7	2	27.92 ± 13.59
Total layers	KBD (n = 22)	0	0	11	11	53.32 ± 14.58*

ISSN: 1749-799X