Difference in apoptosis-associated genes expression profiling and immunohistology analysis between Kashin-Beck disease and primary osteoarthritis

Kashin-Beck disease (KBD) is a chronic and deformed endemic osteoarthritis, without fully known etiology. As compared to primary osteoarthritis (POA), its pathogenesis still exists controversial. We performed this study to discriminate the difference in genes expression involved in apoptosis from KBD cartilages and POA cartilages. Microarray analysis and Ingenuity Pathway Analysis (IPA) were used to identify the molecular mechanisms/canonical pathways implicated in KBD arthritis. Immunohistochemistry staining was carried out to detect tissue distribution of PDCD5 and EGR1 in the knee cartilages from KBD and POA. The 23 up-regulated apoptosis-related genes with >2-fold change were identified. "Role of Macrophages, Fibroblasts, and Endothelial Cells in Rheumatoid Arthritis" signaling was screened as the most relevant pathway through IPA. The 8 differentially regulated genes were verified by qRT-PCR analysis. Programmed cell death 5 in middle and deeper zones and early growth response 1 in superficial and middle zones showed protein overexpressed in KBD cartilage samples comparing to those in POA cartilage samples. Data indicates a higher expression level of apoptosis-related functional genes in KBD articular cartilage compared with POA articular cartilage.