Effect of Estrogen Receptor on Degenerative Change of Articular Cartilage in Adult Rabbit Knee

Kim, Jung Man; Chang, Cheong Ho; Kim, Sung Jin

Abstract

The purpose of this study was to evaluate the effect of estrogen receptor on the degenerative change of articular cartilage by observation of different changes of histology, matrix glycosaminoglycan and chondrocyte proliferation. In sixty-four Newzealand rabbits, experimental instability was made to induce degenerative changes by sectioning the anterior cruciate ligament, medial collateral ligament and medial meniscus of the left knees. In the oophorectomy group (32 rabbits), knee surgery was performed at 6 weeks following bilateral oophorectomy. In the non-oophorectomy group (32 rabbits), knee surgery was performed without oophorectomy. Four rabbits were killed at 0, 1, 2, 4, 8, 12, 16, 20 weeks, respectively, after the knee operation. Total immunohistochemical scores of estrogen receptor were evaluated between the two groups. Histologic evaluation of H-E staining was conducted by alcian blue staining. Evaluation of chondrocyte proliferation was carried out by immunohistochemistry using monoclonal antibody to 5-bromo-2 -deoxyuridine. The stainability of each staining was calculated using semi-quantitative analysis and statistical differences were evaluat- ed by ANOVA test and LSD multiple comparison test. Total immunohistochemical scores of estrogen receptor in the non-oophorectomy group were higher than the oophorectomy group (P<0.05). In the non-oophorectomy group, the histologic scores and the histochemical scores of glycosaminoglycan were lower than the oophorectomy group after 4 weeks and 8 weeks respectively (P<0.05). The immunohistochemical score of BrdU was the highest at 2 week and then decreased after 4weeks in both groups. The immunohistologic scores of non-oophorectomy group was significant higher than oophorectomy group between 1 and 4 weeks (P<0.05). Our results suggested that the estrogen might aggravate the degenerative change of the knee joint in rabbits by decreasing matrix glycosaminoglycan and increasing chondrocyte proliferation.