The Roles Of AKT, ERK1/2and Related Molecules In Human Osteoarthritic Chondrocytes

OBJECTIVE: To investigate the role of protein kinase B (AKT) and extracellularsignal regulated kinase(ERK1/2) in normal and osteoarthritis chondrocytes．METHODS: The samples of knee cartilage were obtained from the normal donors(n=5,23-40years old) and the patients undergoing total knee arthroplasty with thediagnosis of OA (n=18,60-78years old)．The chondrocytes were isolated andidentified by Toluidine Blue staining and IHC(typeⅡcollegen); the expression levelsof AKT、p-AKT、ERK1/2、p-ERK1/2、p-P70S6K and PCNA were tested in normaland osteoarthritic chondrocytes by Western blotting. Real-time fluorescencequantitative PCR was used to detect the expression levels of aggrecan and type IIcollagen gene in normal and osteoarthritic chondrocytes; IHC was used to detect theexpression characteristics of p-AKT and p-ERK1/2in the normal and osteoarthriticcartilage.RESULTS: The expression of p-AKT and p-P70S6K in normal chondrocytes ishigher, compared with OA chondrocytes(P<0.05). And the mRNA level of aggrecanand type II collagen in normal chondrocytes is higher than that in OA chondrocytes(P<0.05).The expression of p-ERK1/2and PCNA in normal chondrocytes is lowerthan that in OA chondrocytes(P<0.05)..Meanwhile, the expression of p-AKT innormal cartilage is higher than that in OA cartilage (P<0.05). The expression of p-ERK1/2in OA cartilage is higher than that in normal cartilage (P<0.05).CONCLUSION: AKT might regulate aggrecan and type II collagen synthesis viaP70S6K, and ERK1/2might regulate OA chondrocytes proliferation by increasing theexpression of PCNA. Both AKT and ERK1/2play important roles in the pathogenesisof OA.