The Detection Of Senescence-associated Beta-galactosidase (SA-beta-gal) And C-Fos Protein In The Cartilage Of OA And Their Significance

Objective: To study the expression of senescence-associated beta-galactosidase(SA-beta-gal) and c-Fos protein in the different impaired cartilage of osteoarthritis(OA).To approach the correlation and possible involvement of senescent chondrocyte and c-fos oncogene in pathogenesis and progression of human osteoarthritis .Methods: To collect 50 cartilage specimens from OA and normal joint, on the basis of improved Mankin pathological score to divide into four groups , normal group 9 specimens(group A), mild impaired group 10 specimens(group B), medium impaired group 15 specimens(group C), severe impaired group 13 specimens(group D)(3 specimens discarded because of experimental mistake). Then use the immunohistochemistry to detect the expression of SA-beta-gal and c-Fos protein in the cartilage specimens. To calculate the percentage of the positive chondrocytes and analysis the correlation between the percentage of the positive chondrocytes and the different impaired cartilage.Results:1.There are no SA-beta-gal positive chondrocytes in the group A , the percentage of the SA-beta-gal positive chondrocytes in the group B is 13.00±5.77%,the percentage of the SA-beta-gal positive chondrocytes in the group C is 31.65±6.91%, the percentage of the SA-beta-gal positive chondrocytes in the group D is 51.95±6.21%,there are significant differences between each group (p<0.05) .2. The percentage of the c-Fos protein positive chondrocytes in the group A is 1.08±1.39%, the percentage of the c-Fos protein positive chondrocytes in the group B is 25.76±8.81%, the percentage of the c-Fos protein positive chondrocytes in the group C is 36.70±4.22%, the percentage of the c-Fos protein positive chondrocytes in the group D is 12.37±8.85%, there are significant differences between each group(p<0.05) .3. According to Spearman rank correlation test, the percentage of the SA-beta-gal positive chondrocytes have direct correlation with the improved Mankin pathological score (r=0.940, p<0.05). The percentage of the c-Fos positive chondrocytes have no correlation with the improved Mankin pathological score (r=0.275, P>0.05) . The percentage of the c-Fos positive chondrocytes have no correlation with the percentage of the SA-beta-gal positive chondrocytes (r=0.164, P >0.05) .Conclusion:1.The senescence of chondrocytes maybe is one of important pathogenesis in OA.2.With the cartalege of OA impaired by degrees, the percentage of the senescent chondrocytes increases.3.The expression of c-Fos protein shows no direct correlation with the severity of OA and the percentage of the SA-beta-gal positive chondrocytes,but increases in the mild and medium impaired cartilage, indicate that c-fos oncogene may play an important role in the early and medium stage OA to compensate for cell division.