[Research of the expression of subchondral bone of Indian hedgehog with early experimental osteoarthritis induced by mechanical stress].

To investigate the the expression of subchondral bone of Indian hedgehog(Ihh) with early experimental osteoarthritis induced by mechanical stress. The animals were equally divided into two groups: experimental group(E-group, =15) and control group(S-group, =15). The right knee joints of E-group underwent surgery, which involved in both medial collateral ligament (MCL) transaction and medial meniscectomy, while the control group was only carried out with a sham operation.The rats were killed at 1, 2 and 4 weeks postsurgery to obtain the right knee joints. Immunostaining and immunofluorescence double staining were performed to evaluate the expression of Ihh in subchondral bone, respectively. The polynuclear giant cells in the subchondral bone of E-Group expressed Ihh in their cytoplasm 1 and 2 weeks post-surgery, except for 4 week, while those of S-Group appeared negative at all three time points postsurgery. There is statistically difference between the mean density of positive area of Ihh in sections of E-group and S-group both in 1 week (E-group: 0.351+ 0.086, S-group: 0.153±0.017, <0.05) and 2 weeks (E-group: 0.303±0.026, S-group: 0.176±0.013, <0.05), but without statistically difference in 4 weeks (E-group: 0.092±0.033, S-group: 0.136±0.014, >0.05) post surgery. Trap positive giant cells in subchondral bone of E-group were also found Ihh positive, which indicated expression of Ihh in osteoclast . Ihh maybe play an important role in pathogenesis of early experimental osteoarthritis.