Objective: To investigate the effect of macrophage colony-stimulating factor-1 (CSF-1) expression in osteosarcoma cells on tumor angiogenesis, and to explore its possible mechanism. Methods: The expressions of CSF-1 and allograft inflammatory factor-1 (AIF-1) in human osteoblasts hFOB1.19, osteosarcoma SAOS-2, MG-63 and U2OS cells were detected by Western blotting. The expressions of AIF-1 and Ras-related C3 botulinum toxin substrate-1 (Rac-1) in osteosarcoma SAOS-2 cells after transfection with siRNA-CSF-1 or siRNAnegative control (siRNA-NC) were detected by Western blotting. The culture supernatant was collected after siRNA-CSF-1 or siRNA-NC was transfected into osteosarcoma SAOS-2 cells, the untransfected SAOS-2 cells were used as the blank control (BC). Then the collected culture supernatant was mixed with the complete medium at a volume ratio of 1∶1 to make the conditioned medium for the culture of human umbilical vein endothelial cells (HUVECs). After treatment with the siRNA-CSF-1 or siRNA-NC conditional medium, the proliferation, migration and tube formation of HUVECs were detected by MTT assay, Transwell chamber assay and tube formation experiment, respectively; The expressions of vascular endothelial growth factor (VEGF) and Rac-1 in HUVECs were detected by Western blotting. After HUVECs were treated with siRNA-CSF-1 conditional medium combined with 0.1% DMSO or Rac-1 activator phorbol 12-myristate 13-acetate (PMA) for 24 h, the cell proliferation, migration and the tube formation were detected by MTT assay, Transwell chamber assay and tube formation experiment, respectively; The expressions of VEGF and Rac-1 in HUVECs were detected again by Western blotting. Results: The expression levels of CSF-1 and AIF-1 proteins in osteosarcoma SAOS-2, MG-63 and U2OS cells were higher than those in osteoblasts hFOB1.19 (all P < 0.05). The expressions of CSF-1 and AIF-1 were positively correlated (R2 = 0.492 2, P = 0.001 2). The expression levels of AIF-1 and Rac-1 in osteosarcoma SAOS-2 cells of siRNA-CSF-1 transfection group were down-regulated (both P < 0.05). After treatment with siRNA-CSF-1 conditional medium, the proliferation, migration and tube formation abilities of HUVECs were decreased (all P < 0.05), and the expression levels of VEGF and Rac-1 were down-regulated (both P < 0.05). Whereas Rac-1 activator reversed the effects of siRNA-CSF-1 conditional medium on the proliferation, migration, tube formation as well as VEGF and Rac-1 expressions of HUVECs (all P < 0.05). Conclusion: CSF-1 in osteosarcoma cells may promote the tumor angiogenesis by AIF-1/ Rac-1 pathway.

【Objective】 To compare the short-term clinical effects of oblique lateral interbody fusion （OLIF） and transforaminal lumbar interbody fusion （TLIF） for treating single-segment lumbar spondylolisthesis. 【Methods】 We retrospectively analyzed the data of 68 patients with single-segment degenerative lumbar spondylolisthesis from January 2019 to February 2020. According to different surgical methods， the patients were divided into OLIF+ anterior screw fixation group （33 cases） and TLIF + posterior pedicle screw fixation group （35 cases）. The operation time， intraoperative blood loss， postoperative drainage， postoperative hospital stay and complication rate were compared between the two groups of patients. The disc height （DH）， lumbar lordosis （LL）， fused segmental lordosis （FSL）， foraminal height （FH）， and spondylolisthesis angle （SA） were measured before and after surgery and during follow-up. The visual analogue scale （VAS） of waist pain and the Oswestry disability index （ODI） were used to evaluate the short-term clinical efficacy. 【Results】 The operation time， intraoperative blood loss， postoperative drainage， and postoperative hospital stay were less in OLIF group than in TLIF group （all P<0.05）. There was no statistically significant difference in VAS or ODI scores between the two groups at the last follow-up after surgery （both P>0.05）. The two groups had statistically significant differences in DH and FH after surgery （P<0.05）， but no significant difference in postoperative LL， FSL or SA （all P>0.05）. There were six （18.2%） and five （14.3%） cases of complications in OLIF group and TLIF group， respectively， with no significant difference （P>0.05）. 【Conclusion】 OLIF and TLIF are equally safe and effective in treating single-segment lumbar spondylolisthesis. However， OLIF combined with anterior screw fixation has the advantages of less surgical trauma， less blood loss， shorter operation time， reduced postoperative hospital stay and shorter recovery time. Therefore， it is a more minimally invasive surgical option.