ABSTRACT
Objective To explore the proliferative changes and clinical significance of osteoclasts (OC) in various stages of osteoarthritis (OA). Methods Twenty healthy adult male SD rats were made the model by modified Hulht procedure,the left knee served as the control group and the right knee as the OA model group. The total knee joint (n=5) was collected at postoperative 1, 2,4,8 weeks, fixed at 4 ℃ 4% poly formaldehyde (PFA) liquid, embedded by paraffin for conducting sections, and stained by TRAP,toluidine blue(TB) and safranine O (Saf O)fast staining. Then the cartilage morphology change was observed and OC positive cells number with TRAP staining were semi-quantitatively detected,the OA cartilage destruction progression was evaluated by Mankin's method and SPSS17.0 statistics software was used to conduct statistical analysis. Results OC in the two groups showed the transient change of rapidly increasing and then decreasing. The OC number at 1 week in the control group (left knee) was (65.20±4.12) cells/mm2 ,and was gradually reduced at 2,4 weeks,which were (47.20±4.31) cells/mm and (26.20±3. 87) cells/mm2 ,which at 8 weeks was almost invisible, the number of cells was (7.00 ± 2.28) cells/mm2 ;the OC number at 1 week in the OA model group (right knee) was (70.40 ± 5.46) cells/mm2 ,increased to (86.20± 5.42)cells /mm2 at 2 weeks, reduced to (38. 0 ± 3.16) cells/mm2 at 4 weeks , was almost invisible at 8 weeks, the number of cells was (6.21 ± 2.93 ) cells/mm2 . The OC number at 2,4 weeks in the model group was significantly higher than that in the control group, the difference had statistical significance (P<0.05). Conclusion Large numbers of osteoclasts are proliferated in the early and middle stages of rat knee osteoarthritis, which indicating that OC might be involved in the formation of osteoarthritis.