Objective To compare the clinical outcome of Asian proximal femoral nail anti-rotation( PFNA-Ⅱ) with different length in the treatment of femoral intertrochanteric fractures(type A1,A2). Methods A study of 80 pa-tients with femoral intertrochanteric fractures (type A1,A2)were conducted, 35 patients of which were operated with short PFNA-Ⅱ (170 mm),while 45 patients with long ones(200,240 mm). Comparisons were made between two groups in operative time, intraoperative bleeding, hidden blood loss, transfusion rate, distance from tip to anterior cortex, rate of nail tip anterior abutment, hospitalization time, Harris hip score and postoperative complications. Re-sults There were no significant differences between two groups in hospitalization time, Harris hip score of and post-operative complications(P>0. 05). Compared with long nails, short nails showed less operative time, fewer intraop-erative bleeding and hidden blood loss, longer distance from tip to anterior cortex and lower transfusion rate and rate of anterior abutment,the differences were statistically significant(P<0. 05). Conclusions Both long and short nails achieve well clinical outcome in the treatment of femoral intertrochanteric fractures(type A1,A2), however short nails demonstrate more therapeutic advantage due to less surgical trauma and better geometric match with femur,thus short nails are preferred in the cases that both long and short nails are acceptable.

BACKGROUND: Recent studies have demonstrated that sterol regulatory element binding protein-2 (SREBP-2) plays a key role in osteoarthritis, but its exact pathogenesis remains incompletely understood yet. OBJECTIVE:To investigate the expression of SREBP-2 in the process of interleukin-1β-induced articular chondrocyte degenerationin vitro. METHODS: Articular chondrocytes obtained from C57BL/6J mice were culturedin vitro. After the second passage, cels were randomly divided into four groups: control group, and three experimental groups treated with 10 μg/L interleukin-1β for 24, 48 and 72 hours, respectively. RESULTS AND CONCLUSION:The cels became hypertrophic after being stimulated by interleukin-1β, and the staining of colagen X was positive at 72 hours. MTT assay demonstrated that the cel activity after stimulation with interleukin-1β decreased with time. Results of RT-PCR showed that the expression of SREBP-2 and SREBP cleavage activating protein mRNA was significantly increased after stimulation with interleukin-1βas compared with the control group and increased with time. On the contrary, the expression of aggrecan and colagen II mRNA was decreased with time. It is revealed that interleukin-1β could inhibit the proliferation of regular chondrocytes and the expression of its extracelular matrix, and furthermore, induce chondrocyte hypertrophy. The expression of SREBP-2 showed a negative relationship with key cartilage genes during this interleukin-1β-induced degeneration.

Objective To observe the effect of tumor necrosis factor-α (TNF-o) on the catabolism of chondrocyte extracellular matrix.Methods Articular cartilage obtained from C57BL/6J mice was digested and cultured in vitro.After the second passage, cells were randomly divided into four groups: group 1 (control group), and three experimental groups treated with 10 μg/L TNF-α for 24, 48 and 72 h respectively.Inverted microscope was employed to observe the cells and immunocytochemistry staining was used to identify chondrocyte.The proliferation of each group was measured by thiazolyl blue (MTT) colorimetry.Rreal-time quantitative polymerase chain reaction (Real-time PCR) was used to detect the mRNA expression of matrix metalloproteinase-13 (MMP-13), sterol-regulatory element binding protein (SREBP)-2, aggrecan and collagen Ⅱ.Results After consecutive passages, the primary chondrocytes had transformed into circle or polygonal shapes.Immunocytochemistry staining showed the second passage chondrocytes which cytoplasm was stained claybank were positive for anti-collagen Ⅱ antibody.MTT assay demonstrated that the absorbance (A) value was significantly lower in each TNF-α experimental group than in the control group (24 h: 86.7％, 48 h: 78.0％, 72 h: 73.5％).Real-time PCR results showed that the expression of MMP-13 and SREBP-2 mRNA was significantly increased (P ＜0.01) in each TNF-oα experimental group as compared with the control group and increased with time [24 h: 0.142 ±0.073, 1.555 ±0.087 (P ＜0.05);48 h: 0.178±0.005, 1.917 ±0.153 (P ＜0.01);72 h: 0.197 ±0.062, 2.187 ±0.135 (P ＜0.01)].On the contrary, the expression of aggrecan and collagen Ⅱ mRNA was decreased in each TNF-α experimental group and decreased with time [24 h : 0.689 ±0.064, 0.567±0.038 (P＜0.05);48 h: 0.620±0.049 (P＜0.01), 0.304±0.029 (P＜0.05);72 h: 0.114 ±0.078, 0.092 ±0.009 (P ＜0.01)].Conclusion TNF-α could induce chondrocyte to produce MMP-13, which leads to break the balance of the extracellular matrix metabolism and promotes the catabolism.In addition, the expression of SREBP-2 showed a negative relationship with key cartilage genes during this process.