OBJECTIVETo explore the effects of Pilose antler polypeptide on apoptosis of chondrocyte and related cytokines in experimental knee osteoarthritis.

METHODSTotally 64 New Zealand White rabbits of 6 months old were randomly divided into 2 groups:normal group(n=8)and model group (n=56). Model group was surgically induced into knee osteoarthritis model by method of Hulth. After successful modeling,the rabbits of model group were further divided into 2 groups: Pilose antler polypeptide-treatment group (n=24) and control group (n=24). Pilose antler polypeptide-treatment group received 0.5 ml intraarticular injection of Pilose antler polypeptide dilution liquid once per 2 days for 30 days while control group received 0.5 ml intra-articular injection of physiological saline. On days 7, 15 and 30 after intervention, articular cartilage samples and synovial fluid were collected respectively. The morphological changes of articular cartilage under optical microscope and the structural change of chondrocyte were observed by transmission electron microscopy. The levels of interleukin-1beta and tumor necrosis factor-alpha in synovial fluid was detected by Enzyme-linked Immunosorbent Assay.

RESULTSAlong with the extending of time, articular cartilage degenerated gradually and chondrocytes apoptosis increased significantly. On days 7,15 and 30 after intervention, the chondrocyte apoptosis index of the Pilose antler polypeptide-treatment group were (20.30 +/- 1.23), (28.60 +/- 2.37), (37.10 +/- 1.82) and those of control group were (31.50 +/- 2.44), (34.40 +/- 1.77), (42.30 +/- 2.33). There were significant differences between them (P<0.05). At the same time, the chondrocyte apoptosis index of the Pilose antler polypeptide-treatment group were lower than those of control group,which had a statistical significance (P<0.05). On days 7,15 and 30 after intervention, the levels of interleukin-1beta in synovia fluid of Pilose antler polypeptide-treatment group were (15.81 +/- 1.26), (12.59 +/- 1.42), (9.57 +/- 0.92) microg/L and the level of tumor necrosis factor-alpha were (48.47 +/- 2.64), (43.46 +/- 1.33), (40.96 +/- 1.05) microg/L, with statistical differences(P<0.05). The levels of interleukin-1beta in synovia fluid of control group were (18.92 +/- 1.83), (20.25 +/- 2.76), (22.13 +/- 2.24) microg/L and the levels of tumor necrosis factor-alpha were (57.92 +/- 2.12), (60.25 +/- 1.48), (63.35 +/- 2.15) microg/L. At the same period,the levels of interleukin-1beta and tumor necrosis factor-alpha were lower than those of the control group,which had a statistical significance (P<0.05).

CONCLUSIONPilose antler polypeptide can inhibit chondrocytes apoptosis, decrease the levels of interleukin-1beta and tumor necrosis factor-alpha and delay the degeneration of articular cartilage to some extent.