Objective: To investigate the effects of adipose-derived stem cells (ADSCs) and endothelial cells (ECs) on the survival and neovascularization of fat tissue transplants.
Methods: The ADSCs were isolated by collagenase digestion from the adipose tissues voluntarily donated by the patients undergoing mastectomy, and subcultured. The passage 3 ADSCs were used for subsequent experiments. The residual fat tissues were used to prepare fat particles (FPs). The human umbilical vein endothelial cells (HUVECs) were used as ECs for subsequent experiments. Eighty healthy male nude mice, aged 4-6 weeks, were randomly divided into 4 groups ( n=20). The mice were received subcutaneous injection at the dorsum of 1 mL FPs+0.3 mL normal saline (NS) in control group, 1 mL FPs+2×10 6 ECs+0.3 mL NS in ECs group, 1 mL FPs+2×10 6 ADSCs+0.3 mL NS in ADSCs group, and 1 mL FPs+1×10 6 ECs+1×10 6 ADSCs+0.3 NS in ADSCs+ECs group. General observations of the injection sites were performed, and the survival of the mice was recorded. At 2, 4, 8, and 12 weeks after injection, grafted fat tissues were firstly assessed by ultrasonography, then they were collected for volume measurement (water displacement method) and histology observation (HE staining and immunofluorescence staining).
Results: All mice survived until the end of experiment. At each time point, no significant difference was noted between groups in ultrasonography assay. There was no significant blood flow signal in the grafted fat tissues, or cysts, calcification, solid occupying in recipient area. Generally, the volume of grafted fat tissues decreased with time in all groups. Specifically, the volumes of grafted fat tissues were larger in ADSCs group and ADSCs+ECs group than that in control group and ECs group ( P<0.05) at each time point, and in ADSCs group than in ADSCs+ECs group ( P<0.05) at 8 and 12 weeks. HE staining showed that all groups had similar tendencies in general histology changes, and remodeling in ADSCs group was the fastest than in the other groups. By immunofluorescence staining for neovascularization, the new vessels in all groups were increasing with time. The vessel densities were higher in ECs group, ADSCs group, and ADSCs+ECs group than in control group ( P<0.05) at each time point, in ADSCs group than in ECs group and ADSCs+ECs group ( P<0.05) at 4 weeks, in ADSCs group and ADSCs+ECs group than in ECs group ( P<0.05) at 8 and 12 weeks.
Conclusion: ADSCs can significantly increase the survival of transplanted fat tissue, which may be related to promoting the neovascularization.
目的: 探讨脂肪来源干细胞（adipose-derived stem cells，ADSCs）及血管内皮细胞（endothelial cells，ECs）对脂肪移植术后血管新生及脂肪成活的影响。.
方法: 取乳房切除术患者自愿捐赠的脂肪组织，采用胶原酶消化法分离培养 ADSCs，取第 3 代细胞进行实验；同时制备游离脂肪颗粒。取健康 4～6 周龄雄性裸鼠 80 只，随机分为 4 组（ n=20），分别于裸鼠背部皮下注射 1 mL 脂肪颗粒+0.3 mL 生理盐水（对照组）、1 mL 脂肪颗粒+2×10 6 个人脐静脉内皮细胞株（human umbilical vein endothelial cells，HUVECs）+0.3 mL 生理盐水（ECs 组）、1 mL 脂肪颗粒+2×10 6 个 ADSCs+0.3 mL 生理盐水（ADSCs 组）、1 mL 脂肪颗粒+1×10 6 个 HUVECs+1×10 6 个 ADSCs+0.3 mL 生理盐水（ADSCs+ECs 组）。注射后观察各组裸鼠存活情况，大体观察背部移植区色泽、形状。2、4、8、12 周时背部移植区行超声影像学观察，取标本采用排水法测量其体积，组织学观察移植脂肪大体结构变化情况，免疫荧光染色观察血管新生情况。.
结果: 各组裸鼠均存活至实验完成。移植后各时间点各组超声检测结果无明显差异，移植脂肪内部均未见明显血流信号，未见囊肿、钙化、实性占位等异常表现。移植后各时间点，ADSCs 组及 ADSCs+ECs 组移植脂肪体积均高于 ECs 组及对照组（ P<0.05）；且 8、12 周时 ADSCs 组明显高于 ADSCs+ECs 组（ P<0.05）。HE 染色示移植后各组组织学形态变化趋势相似，但 ADSCs 组组织重塑速度快于其他各组。免疫荧光染色示随时间延长各组新生血管逐渐增加，各时间点 ECs 组、ADSCs 组、ADSCs+ECs 组微血管密度均高于对照组（ P<0.05）；4 周时 ADSCs 组微血管密度高于 ECs 组及 ADSCs+ECs 组（ P<0.05）；8、12 周时 ADSCs 组及 ADSCs+ECs 组高于 ECs 组（ P<0.05），ADSCs 组及 ADSCs+ECs 组间比较差异无统计学意义（ P>0.05）。.
结论: ADSCs 可提高移植脂肪存活率，且该促进作用可能与促进血管新生相关。.
Keywords: Fat grafting; adipose-derived stem cells; endothelial cells; nude mouse.