[Effects and mechanism of hepatocyte growth factor-modified human adipose mesenchymal stem cells on wound healing of full-thickness skin defects in diabetic rats].

Objective: To investigate the effects and mechanism of hepatocyte growth factor (HGF)-modified human adipose mesenchymal stem cells (ADSCs) on the wound healing of full-thickness skin defects in diabetic rats. Methods: The experimental research method was adopted. The discarded abdominal adipose tissue was collected from a 35-year-old healthy female who underwent abdominal liposuction in the Department of Plastic Surgery of the First Affiliated Hospital of Air Force Medical University in December 2019. The long spindle-shaped primary ADSCs were obtained by collagenase digestion, and the third passage of cells were identified by flow cytometry to positively express ADSCs surface markers CD29 and CD90 and negatively express CD34 and CD45. The third passage of ADSCs were used for the subsequent experiments. ADSCs were transfected with lentivirus-mediated HGF for 4 h (obtaining HGF modified ADSCs) and then routinely cultured for 24 h. The cell morphology was observed under an inverted phase contrast microscope, and the transfection rate was calculated. Eighty-one male Sprague-Dawley rats aged 4 weeks were induced into diabetic rat model by high glucose and high fat diet combined with streptozotocin injection. A full-thickness skin defect wound of 1.5 cm×1.5 cm was made on the back of each rat. The injured rats were divided into phosphate buffer solution (PBS) group, ADSCs alone group, and HGF-modified ADSCs group according to the random number table, with 27 rats in each group. The rats were injected with the same volume of corresponding substances around the wound on post injury day (PID) 1, 3, and 7, respectively. Nine rats in each group were selected according to the random number table, the wound area of whom was measured on PID 0 (immediately), 3, 7, 10, and 14 (after injection on injection day), and the wound healing rates on PID 3, 7, 10, and 14 were calculated. Nine remaining rats in each group were sacrificed after injection on PID 3 and 7, respectively, and the skin tissue around the wound were collected. The mRNA expressions of inflammatory factors such as tumor necrosis factor α (TNF-α), interleukin 1β (IL-1β), and IL-10 on PID 3 and collagen type Ⅰ and Ⅲ on PID 7 were detected by real-time fluorescent quantitative reverse transcription polymerase chain reaction. The expression level of vascular endothelial growth factor (VEGF) was detected by enzyme-linked immunosorbent assay on PID 7. The protein expression of nuclear factor κb-p65 on PID 3 and phosphorylation level of protein kinase B (Akt) on PID 7 were detected by Western blotting. Data were statistically analyzed with analysis of variance for repeated measurement, one-way analysis of variance, least significant difference t test, and Bonferroni correction. Results: After 24 h of culture, the HGF-transfected human ADSCs showed good morphology, which was not different with the non-transfected ADSCs, and the transfection rate reached 90%. On PID 3, 7, 10, and 14, the wound healing rates of rats in HGF-modified ADSCs group were (31.5±1.0)%, (75.2±2.0)%, (92.2±1.3)%, and (99.1±1.8)%, respectively, being significantly higher than (21.4±1.3)%, (61.4±1.5)%, (80.1±2.1)%, and (92.4±1.8)% in PBS group and (25.1±2.1)%, (67.2±1.3)%, (89.3±1.4)%, and (95.1±2.1)% in ADSCs alone group (t=1.452, 0.393, 0.436, 0.211, 4.982, 3.011, 4.211, 7.503, P<0.05 or P<0.01). On PID 3, compared with those in PBS group and ADSCs alone group, the mRNA expressions of TNF-α and IL-1β and protein expression of nuclear factor κb-p65 in the skin tissue around the wound of rats in HGF-modified ADSCs group were significantly decreased (t=7.281, 17.700, 9.447, 6.231, 13.083, 7.783, P<0.01), and the mRNA expression of IL-10 in the skin tissue around the wound of rats in HGF-modified ADSCs group was significantly increased (t=-6.644, -6.381, P<0.01). On PID 7, compared with those in PBS group and ADSCs alone group, the mRNA expressions of collagen type Ⅰ and Ⅲ, the expression level of VEGF, and the phosphorylation level of Akt in the skin tissue around the wound of rats in HGF-modified ADSCs group were significantly increased (t=-5.126, -4.347, -5.058, -3.367, -10.694, -19.876, -4.890, -6.819, P<0.05 or P<0.01). Conclusions: HGF-modified human ADSCs can significantly promote the wound healing of full-thickness skin defects in diabetic rats. The mechanism may be related to the inhibition of TNF-α and IL-1β expression, the promotion of IL-10, collagen type Ⅰ and Ⅲ, and VEGF expression, which could be related to the inhibition of nuclear factor κB signaling pathway, and the promotion of Akt signaling pathway.目的： 探讨肝细胞生长因子（HGF）修饰人脂肪间充质干细胞（ADSC）对糖尿病大鼠全层皮肤缺损创面愈合的影响及其机制。 方法： 采用实验研究方法。取2019年12月于空军军医大学第一附属医院整形科行腹部抽脂术的1名35岁健康女性术后弃用腹部脂肪组织，采用胶原酶消化法获取呈长梭形的原代ADSC，其第3代细胞经流式细胞仪鉴定阳性表达ADSC表面标志物CD29、CD90，阴性表达CD34、CD45。取第3代ADSC进行后续实验。采用慢病毒介导的HGF转染ADSC 4 h（获得HGF修饰ADSC）后，常规培养24 h，倒置相差显微镜下观察细胞形态并计算转染率。取81只4周龄雄性SD大鼠，通过高糖高脂饮食联合链脲佐菌素注射诱导为糖尿病大鼠模型后，在每只大鼠背部制作1.5 cm×1.5 cm全层皮肤缺损创面。采用随机数字表法，将致伤大鼠分为磷酸盐缓冲液（PBS）组、单纯ADSC组、HGF修饰ADSC组，每组27只，均分别于伤后1、3、7 d在创周注射相同体积的相应物质。采用随机数字表法选取各组9只大鼠，于伤后0（即刻）、3、7、10、14 d（注射日注射后）测量创面面积并计算伤后3、7、10、14 d创面愈合率。伤后3、7 d行当日注射后分别处死各组剩余大鼠中的9只，取创周皮肤组织，采用实时荧光定量反转录PCR法检测伤后3 d肿瘤坏死因子α（TNF-α）、白细胞介素1β（IL-1β）、IL-10及伤后7 d Ⅰ、Ⅲ型胶原的mRNA表达，采用酶联免疫吸附测定法检测伤后7 d血管内皮生长因子（VEGF）的表达水平，采用蛋白质印迹法检测伤后3 d核因子κB-p65蛋白表达、伤后7 d蛋白激酶B（Akt）的磷酸化水平。对数据行重复测量方差分析、单因素方差分析、LSD-t检验及Bonferroni校正。 结果： 培养24 h，转染HGF的ADSC形态良好，与未转染ADSC无差异，转染率达90%。伤后3、7、10、14 d，HGF修饰ADSC组大鼠创面愈合率分别为（31.5±1.0）%、（75.2±2.0）%、（92.2±1.3）%、（99.1±1.8）%，显著高于PBS组的（21.4±1.3）%、（61.4±1.5）%、（80.1±2.1）%、（92.4±1.8）%和单纯ADSC组的（25.1±2.1）%、（67.2±1.3）%、（89.3±1.4）%、（95.1±2.1）%（t=1.452、0.393、0.436、0.211，4.982、3.011、4.211、7.503，P<0.05或P<0.01）。伤后3 d，与PBS组和单纯ADSC组比较，HGF修饰ADSC组大鼠创周皮肤组织中TNF-α、IL-1β的mRNA表达及核因子κB-p65的蛋白表达均显著降低（t=7.281、17.700、9.447，6.231、13.083、7.783，P<0.01），IL-10的mRNA表达显著升高（t=-6.644、-6.381，P<0.01）。伤后7 d，与PBS组和单纯ADSC组比较，HGF修饰ADSC组大鼠创周皮肤组织中Ⅰ、Ⅲ型胶原的mRNA表达及VEGF表达水平、Akt磷酸化水平均明显升高（t=-5.126、-4.347、-5.058、-3.367，-10.694、-19.876、-4.890、-6.819，P<0.05或P<0.01）。 结论： HGF修饰的人ADSC可显著促进糖尿病大鼠全层皮肤缺损创面愈合，其机制可能与抑制TNF-α、IL-1β表达，促进IL-10、Ⅰ型胶原、Ⅲ型胶原及VEGF的表达相关，且可能与抑制核因子κB信号通路、促进Akt信号通路有关。.