Objective:To investigate the influence and mechanism of bone marrow mesenchymal stem cells (BMSCs) overexpressing growth arrest specific 6, i.e. GAS6/BMSCs on full-thickness skin defect wounds in diabetic mice.Methods:This study was an experimental study. Twelve 8-week-old male C57BL/6J mice were divided into a control wound group with only full-thickness skin defects and a diabetic wound group with diabetic full-thickness skin defects according to the random number table method, with 6 mice in each group. The wound healing rates were calculated at 3, 7, 14, and 21 days after injury. At 21 days after injury, wound tissue specimens were collected for hematoxylin-eosin staining to observe the histopathological conditions; Masson staining was performed to detect collagen deposition; immunohistochemical staining was performed to detect the number of proliferating cell nuclear antigen (PCNA)-positive cells and CD31-positive cells, representing cell proliferation and capillary density, respectively; immunofluorescence staining was performed to detect the number of F4/80 and myeloperoxidase (MPO) double-positive cells, indicating efferocytosis. Two 4-week-old male C57BL/6J mice were used to extract BMSCs, and GAS6/BMSCs were constructed through adenovirus transfection and successfully identified. Eighteen 8-week-old male C57BL/6J mice were used to create diabetic full-thickness skin defect wound models and divided into phosphate buffered solution (PBS) group, BMSC group, and GAS6/BMSC group (with 6 mice in each group) according to the random number table method. Immediately after injury, PBS, BMSC single-cell suspension, and GAS6/BMSC single-cell suspension were injected locally into the wounds of the three groups of mice, respectively. The wound healing rates were calculated, and the cell proliferation, capillary density, and efferocytosis were detected at the same time points as the previous experiments.Results:At 3, 7, 14, and 21 days after injury, the wound healing rates of mice in diabetic wound group were significantly lower than those in control wound group (with t values of 7.99, 8.62, 9.80, and 5.85, respectively, P<0.05). Compared with those in control wound group, the wound tissue of mice in diabetic wound group showed the infiltration of a large number of inflammatory cells and reduced collagen deposition at 21 days after injury. At 21 days after injury, the number of PCNA-positive cells and CD31-positive cells in the wound tissue of mice in diabetic wound group were significantly less than that in control wound group (with t values of 6.61 and 5.38, respectively, P<0.05). At 21 days after injury, the number of F4/80 and MPO double-positive cells in the wound tissue of mice in diabetic wound group was 3.3±0.8, which was significantly less than 12.7±1.8 in control wound group ( t=11.00, P<0.05). At 14 and 21 days after injury, the wound healing rates of mice in BMSC group were significantly higher than those in PBS group ( P<0.05); at 3, 7, 14, and 21 days after injury, the wound healing rates of mice in GAS6/BMSC group were significantly higher than those in BMSC group ( P<0.05). At 21 days after injury, the number of PCNA-positive cells in the wound tissue of mice in BMSC group was significantly higher than that in PBS group ( P<0.05), and the number of PCNA-positive cells and CD31-positive cells in the wound tissue of mice in GAS6/BMSC group were significantly higher than that in BMSC group ( P<0.05). At 21 days after injury, the number of F4/80 and MPO double-positive cells in the wound tissue of mice in BMSC group was 4.2±1.2, which was similar to 3.5±1.1 in PBS group ( P>0.05); the number of F4/80 and MPO double-positive cells in the wound tissue of mice in GAS6/BMSC group was 8.2±1.2, which was significantly more than that in BMSC group ( P<0.05). Conclusions:Dysfunctional efferocytosis of macrophage exists in the full-thickness skin defect wounds of diabetic mice, while GAS6/BMSC can promote wound healing by restoring the efferocytosis of macrophages.

Objective:To investigate the influence and mechanism of bone marrow mesenchymal stem cells (BMSCs) overexpressing growth arrest specific 6, i.e. GAS6/BMSCs on full-thickness skin defect wounds in diabetic mice.Methods:This study was an experimental study. Twelve 8-week-old male C57BL/6J mice were divided into a control wound group with only full-thickness skin defects and a diabetic wound group with diabetic full-thickness skin defects according to the random number table method, with 6 mice in each group. The wound healing rates were calculated at 3, 7, 14, and 21 days after injury. At 21 days after injury, wound tissue specimens were collected for hematoxylin-eosin staining to observe the histopathological conditions; Masson staining was performed to detect collagen deposition; immunohistochemical staining was performed to detect the number of proliferating cell nuclear antigen (PCNA)-positive cells and CD31-positive cells, representing cell proliferation and capillary density, respectively; immunofluorescence staining was performed to detect the number of F4/80 and myeloperoxidase (MPO) double-positive cells, indicating efferocytosis. Two 4-week-old male C57BL/6J mice were used to extract BMSCs, and GAS6/BMSCs were constructed through adenovirus transfection and successfully identified. Eighteen 8-week-old male C57BL/6J mice were used to create diabetic full-thickness skin defect wound models and divided into phosphate buffered solution (PBS) group, BMSC group, and GAS6/BMSC group (with 6 mice in each group) according to the random number table method. Immediately after injury, PBS, BMSC single-cell suspension, and GAS6/BMSC single-cell suspension were injected locally into the wounds of the three groups of mice, respectively. The wound healing rates were calculated, and the cell proliferation, capillary density, and efferocytosis were detected at the same time points as the previous experiments.Results:At 3, 7, 14, and 21 days after injury, the wound healing rates of mice in diabetic wound group were significantly lower than those in control wound group (with t values of 7.99, 8.62, 9.80, and 5.85, respectively, P<0.05). Compared with those in control wound group, the wound tissue of mice in diabetic wound group showed the infiltration of a large number of inflammatory cells and reduced collagen deposition at 21 days after injury. At 21 days after injury, the number of PCNA-positive cells and CD31-positive cells in the wound tissue of mice in diabetic wound group were significantly less than that in control wound group (with t values of 6.61 and 5.38, respectively, P<0.05). At 21 days after injury, the number of F4/80 and MPO double-positive cells in the wound tissue of mice in diabetic wound group was 3.3±0.8, which was significantly less than 12.7±1.8 in control wound group ( t=11.00, P<0.05). At 14 and 21 days after injury, the wound healing rates of mice in BMSC group were significantly higher than those in PBS group ( P<0.05); at 3, 7, 14, and 21 days after injury, the wound healing rates of mice in GAS6/BMSC group were significantly higher than those in BMSC group ( P<0.05). At 21 days after injury, the number of PCNA-positive cells in the wound tissue of mice in BMSC group was significantly higher than that in PBS group ( P<0.05), and the number of PCNA-positive cells and CD31-positive cells in the wound tissue of mice in GAS6/BMSC group were significantly higher than that in BMSC group ( P<0.05). At 21 days after injury, the number of F4/80 and MPO double-positive cells in the wound tissue of mice in BMSC group was 4.2±1.2, which was similar to 3.5±1.1 in PBS group ( P>0.05); the number of F4/80 and MPO double-positive cells in the wound tissue of mice in GAS6/BMSC group was 8.2±1.2, which was significantly more than that in BMSC group ( P<0.05). Conclusions:Dysfunctional efferocytosis of macrophage exists in the full-thickness skin defect wounds of diabetic mice, while GAS6/BMSC can promote wound healing by restoring the efferocytosis of macrophages.

Objective To compare the genetic barriers to development of primary mutations related to drug resistance to protease inhibitors (PI), nucleioside reverse transcriptase inhibitors ( NRTI ), and non-nucleioside reverse transcriptase inhibitors ( NNRTI ) among human immunodeficiency virus (HIV)-1 CRF01_AE, CRF07_BC, and CRF08_BC strains, and to understand the difference of varying patterns of drug resistance related mutations within these subtypes. Methods One hundred and ninety naive HIV-positive subjects from Nanning City and Liuzhou City, Guangxi Zhuang Autonomous Region, were recruited. Peripheral blood samples were collected from all participants. HIV-1 RNAs were extracted from plasma, and the pol regions were amplified and sequenced. Sequences were subjected to phylogenetic analysis to determine the subtypes of HIV-1 isolates. Nucleotide transitions and transversions were counted for each primary mutation in these sequences. According to the phenomena that transitions occur on average 2. 5 times frequently than transversions, each transition was scored as 1, and each transversion scored as 2. 5. The sum of the scores for a particular substitution was calculated, and this value was taken as the genetic barrier to development of this mutation. Then, the differences of genetic barriers among the subtypes were assessed by Kruskal-Wallis test and Nemenyi test. Results A total of 123 sequences of CRF01_AE,CRF07_BC and CRF08_BC strains were selected. CRF08_BC had a lower genetic barrier for T/S69Dsubstitution than CRF01_AE and CRF07_BC (χ2 =107. 501, P＜0.01), while CRF01_AE and CRF07_BC had lower genetic barriers for V118I and L210W substitution than CRF08_BC. In addition,CRF07_BC had a decreased genetic barrier for V106M compared with CRF01_AE and CRF08_BC.Conclusions In the presence of the same selective pressure, subtypes CRF01_AE and CRF07_BC may be more likely to develop V118I and L210W substitution than CRF08_BC. However, CRF08_BC may be more likely to develop T/S69D substitution than CRF01_AE and CRF07_BC. Meanwhile, CRF07_BC may be easier to develop V106M substitution than CRF01_AE and CRF08_BC.