Background Bacteria are the most diverse and widely sourced microorganisms in the indoor air of subway stations, where pathogenic bacteria can spread through the air, leading to increased health risks. Objective To understand the status and distribution characteristics of indoor air bacterial pollution in subway stations and compartments in a city of Central South China, and to provide a scientific basis for formulating intervention measures to address indoor air bacteria pollution in subways. Methods Three subway stations and the compartments of trains parking there in a city in Central South China were selected according to passenger flow for synchronous air sampling and monitoring. Temperature, humidity, wind speed, carbon dioxide (CO₂), fine particulate matter (PM_2.5), and inhalable particulate matter (PM₁₀) were measured by direct reading method. In accordance with the requirements of Examination methods for public places-Part 3: Airborne microorganisms (GB/T 18204.3-2013), air samples were collected at a flow rate of 28.3 L·min⁻¹, and total bacterial count was estimated. Bacterial microbial species were identified with a mass spectrometer and pathogenic bacteria were distinguished from non-pathogenic bacteria according to the Catalogue of pathogenic microorganisms transmitted to human beings issued by National Health Commission. Kruskal-Wallis H test was used to compare the subway hygiene indicators in different regions and time periods, and Bonferroni test was used for pairwise comparison. Spearman correlation test was used to evaluate the correlation between CO₂ concentration and total bacterial count. Results The pass rates were 100.0% for airborne total bacteria count, PM_2.5, and PM₁₀ in the subway stations and train compartments, 94.4% for temperature and wind speed, 98.6% for CO₂, but 0% for humidity. The overall median (P₂₅, P₇₅) total bacteria count was 177 (138,262) CFU·m⁻³. Specifically, the total bacteria count was higher in station halls than in platforms, and higher during morning peak hours than during evening peak hours (P<0.05). A total of 874 strains and 82 species were identified by automatic microbial mass spectrometry. The results of identification were all over 9 points, and the predominant bacteria in the air were Micrococcus luteus (52.2%) and Staphylococcus hominis (9.8%). Three pathogens, Acinetobacter baumannii (0.3%), Corynebacterium striatum (0.1%), and Staphylococcus epidermidis bacilli (2.2%) were detected in 23 samples (2.6%), and the associated locations were mainly distributed in train compartments during evening rush hours. Conclusion The total bacteria count in indoor air varies by monitoring sites of subway stations and time periods, and there is a risk of opportunistic bacterial infection. Attention should be paid to cleaning and disinfection during peak passenger flow hours in all areas.

Objective:In chronic hepatitis B (CHB) patients with previous 96-week treatment with tenofovir amibufenamide (TMF) or tenofovir disoproxil fumarate (TDF), we investigated the efficacy of sequential TMF treatment from 96 to 144 weeks.Methods:Enrolled subjects who were previously assigned (2:1) to receive either 25 mg TMF or 300 mg TDF with matching placebo for 96 weeks received extended or switched TMF treatment for 48 weeks. Efficacy was evaluated based on virological, serological, biological parameters, and fibrosis staging. Statistical analysis was performed using the McNemar test, t-test, or Log-Rank test according to the data. Results:593 subjects from the initial TMF group and 287 subjects from the TDF group were included at week 144, with the proportions of HBV DNA<20 IU/ml at week 144 being 86.2% and 83.3%, respectively, and 78.1% and 73.8% in patients with baseline HBV DNA levels ≥8 log10 IU/ml. Resistance to tenofovir was not detected in both groups. For HBeAg loss and seroconversion rates, both groups showed a further increase from week 96 to 144 and the 3-year cumulative rates of HBeAg loss were about 35% in each group. However, HBsAg levels were less affected during 96 to 144 weeks. For patients switched from TDF to TMF, a substantial further increase in the alanine aminotransferase (ALT) normalization rate was observed (11.4%), along with improved FIB-4 scores.Conclusion:After 144 weeks of TMF treatment, CHB patients achieved high rates of virological, serological, and biochemical responses, as well as improved liver fibrosis outcomes. Also, switching to TMF resulted in significant benefits in ALT normalization rates (NCT03903796).

Objective:In chronic hepatitis B (CHB) patients with previous 96-week treatment with tenofovir amibufenamide (TMF) or tenofovir disoproxil fumarate (TDF), we investigated the safety profile of sequential TMF treatment from 96 to 144 weeks.Methods:Enrolled subjects that previously assigned (2:1) to receive either 25 mg TMF or 300 mg TDF with matching placebo for 96 weeks received extending or switching TMF treatment for 48 weeks. Safety profiles of kidney, bone, metabolism, body weight, and others were evaluated.Results:666 subjects from the initial TMF group and 336 subjects from TDF group with at least one dose of assigned treatment were included at week 144. The overall safety profile was favorable in each group and generally similar between extended or switched TMF treatments from week 96 to 144. In subjects switching from TDF to TMF, the non-indexed estimated glomerular filtration rate (by non-indexed CKD-EPI formula) and creatinine clearance (by Cockcroft-Gault formula) were both increased, which were (2.31±8.33) ml/min and (4.24±13.94) ml/min, respectively. These changes were also higher than those in subjects with extending TMF treatment [(0.91±8.06) ml/min and (1.30±13.94) ml/min]. Meanwhile, switching to TMF also led to an increase of the bone mineral density (BMD) by 0.75% in hip and 1.41% in spine. On the other side, a slight change in TC/HDL ratio by 0.16 (IQR: 0.00, 0.43) and an increase in body mass index (BMI) by (0.54±0.98) kg/m 2 were oberved with patients switched to TMF, which were significantly higher than that in TMF group. Conclusion:CHB patients receiving 144 weeks of TMF treatment showed favorable safety profile. After switching to TMF, the bone and renal safety was significantly improved in TDF group, though experienceing change in metabolic parameters and weight gain (NCT03903796).

Objective:To investigate the surgical treatment methods of femoral artery pseudoaneurysm combined with infectious wounds and to evaluate the clinical effects.Methods:The retrospective observational research method was used. Twelve patients with femoral artery pseudoaneurysm combined with infectious wounds who met the inclusion criteria were admitted to Nanjing University of Chinese Medicine Wuxi Integrated Traditional Chinese and Western Medicine Hospital (Affiliated Hospital of Jiangnan University) from October 2014 to September 2022, including 6 males and 6 females, aged from 46 to 78 years. In the primary operation, debridement, tumor resection, and artery suture/venous grafting to repair the artery/artery ligation were performed, and the wound area after tumor resection ranged from 4.0 cm×1.5 cm to 12.0 cm×6.5 cm. Wounds that could be sutured were treated with tension reduction suture and extracutaneous continuous vacuum sealing drainage (VSD), while large wounds that could not be sutured were treated with VSD to control infection. In the secondary operation, tension reduction suture was performed to repair the wounds that could be sutured; large wounds were repaired with adjacent translocated flaps with area of 9.0 cm×5.0 cm to 15.0 cm×7.0 cm. Additionally, when the length of the exposed femoral artery was equal to or over 3.0 cm, the wounds were repaired with additional rectus femoris muscle flap with length of 15.0 to 18.0 cm. The donor areas of the flaps were directly sutured. The wound with artery ligation was treated with stamp skin grafting and continuous VSD. The bacterial culture results of the wound exudate samples on admission were recorded. The intraoperative blood loss, the location of femoral artery rupture, the artery treatment method, and the wound repair method in the primary operation were recorded, and the durations of catheter lavage, catheter drainage, and VSD treatment, and the drainage volume after the operation were recorded. The repair method of wounds in the secondary operation, the durations of catheter drainage and VSD treatment, and the total drainage volume after the operation were recorded. The survivals of flap/muscle flap/stamp skin grafts were observed, and the wound healing time was recorded. Follow-up after discharge was performed to evaluate the quality of wound healing and the walking function and to check whether the pulsatile mass disappeared. B-ultrasound or computed tomography angiography (CTA) was performed again to observe potential pseudoaneurysm recurrence and evaluate the patency of blood flow of the femoral artery.Results:The bacterial culture results of wound exudate samples of all the patients were positive on admission. The blood loss was 150 to 750 mL in the primary operation. The arterial ruptures were located in the femoral artery in 8 cases, in the external iliac artery in 2 cases, and in the femoral arteriovenous fistula in 2 cases. Six cases received direct artery suture, 4 cases received autologous great saphenous vein grafting to repair the artery, 1 case received autologous great saphenous vein bypass surgery, and 1 case received artery ligation. The primary wound suture was performed in 4 cases, along with catheter lavage for 3 to 5 days, catheter drainage for 4 to 6 days, VSD treatment for 5 to 7 days, and a total drainage volume of 80 to 450 mL after the surgery. In the secondary operation, the wounds were sutured directly in 3 cases along with catheter drainage for 2 to 3 days, the wound was repaired with scalp stamp skin graft and VSD treatment for 5 days in 1 case, the wounds were repaired with adjacent translocated flaps in 2 cases with catheter drainage for 2 to 3 days, and the wounds were repaired with rectus femoris muscle flaps+adjacent translocated flaps in 2 cases with catheter drainage for 3 to 5 days . The total drainage volume after the secondary operation ranged from 150 to 400 mL. All the skin flaps/muscle flaps/skin grafts survived after operation. The wound healing time ranged from 15 to 36 days after the primary operation. Follow-up of 2 to 8 months after discharge showed that the wounds of all patients healed well. One patient who underwent femoral artery ligation had calf amputation due to foot ischemic necrosis, and the rest of the patients regained normal walking ability. The pulsatile mass disappeared in inguinal region of all patients. B-ultrasound or CTA re-examination in 6 patients showed that the blood flow of femoral artery had good patency, and there was no pseudoaneurysm recurrence.Conclusions:Early debridement, tumor resection, and individualized artery treatment should be performed in patients with femoral artery pseudoaneurysm combined with infected wounds. Besides, proper drainage and personalized repair strategy should be conducted according to the wound condition to achieve a good outcome.

Objective:To explore the clinical effects of fractional carbon dioxide laser combined with autologous fat injection in the treatment of hypertrophic scar after burn.Methods:From April 2018 to April 2019, 12 patients with hypertrophic scar after burn who met the inclusion criteria were admitted to the Department of Plastic Surgery and Burns of Xuzhou Renci Hospital, and were included in this prospective randomized controlled clinical study. There were 7 males and 5 females with age of (32±11) years and scar area of (612±195) cm 2. One scar was selected from each patient and divided into two equal area scars, and they were divided into combined treatment group and laser alone group with 12 scars in each group according to the random number table. The scar in laser alone group was only treated with fractional carbon dioxide laser, while the scar in combined treatment group was injected with autologous granular fat and then treated with fractional carbon dioxide laser. Scars in the two groups were treated once every 2 months, totally 3 times. Before the first treatment and 6 months after the last treatment, the scars in the two groups were evaluated by modified Vancouver Scar Scale (mVSS), hematoxylin-eosin staining and color Doppler ultrasound. Six months after the last treatment, the curative effect of scars in the two groups was evaluated, and the effective number of scar treatment was calculated. The adverse reactions during the whole treatment were recorded. Data were statistically analyzed with independent sample t test, paired sample t test, and McNemar exact probability method test. Results:Six months after the last treatment, the mVSS score of scars in combined treatment group was (4.5±0.4) points, which was significantly lower than (7.8±0.6) points in laser alone group ( t=10.000, P<0.01). Six months after the last treatment, the mVSS scores of scars in combined treatment group and laser alone group were significantly lower than those before the first treatment ((13.5±0.7) and (13.8±0.6) points, t=8.805, 9.010, P<0.01). The effective number of scar treatment in combined treatment group was significantly more than that in laser alone group ( P<0.05). There was no scar aggravation, infection, or other adverse reactions during the treatment of scars in both groups. Before the first treatment, the scars in both groups had large collagen, disordered arrangement, proliferation of capillaries, infiltration of some inflammatory cells, and disappearance of skin appendages. Six months after the last treatment, the scar collagen in both groups was sparse and orderly arranged, and the vascular density was reduced. The improvement of scars in combined treatment group was more obvious than that of laser alone group. Six months after the last treatment, the scar thickness in combined treatment group was significantly smaller than that in laser alone group ( t=2.657, P<0.05). Before the first treatment, the blood flow of scars in both groups was abundant; 6 months after the last treatment, the blood flow of scars in combined treatment group was significantly less than that in laser alone group. Conclusions:Fractional carbon dioxide laser combined with autologous fat injection in the treatment of hypertrophic scar after burn can significantly reduce the pain and itching symptoms of scar, and improve the thickness, texture, and congestion of scar. The combined treatment has synergistic effect and less adverse reactions, providing a more effective treatment for patients with hypertrophic scar.

The modulation of microenvironment is a key technology towards promoting wound repair and skin regeneration. In recent years, a series of new bioactive materials that modulate the microenvironment and cell behaviors have been developed, demonstrating highly efficient capability of inducing wound repair and skin appendage regeneration. This article summarizes the research development of related new bioactive materials and their mechanisms of action.

Objective:To understand the molecular characteristics and correlation among isolated strains of Brucella melitensis (BM) so as to improve the strategies on prevention and control of the disease in Jiangxi province. Methods:A total of 25 strains of BM isolated from human in 17 counties of Jiangxi province were analyzed by multiple locus variable-number tandem repeat analysis (MLVA) method.Results:A total of 25 strains of BM were classified into 24 independent genotypes with similarities between 67.00% and 100.00% and Simpson index between 0.000 and 0.773. There were 3 genotypes in MLVA8, including 60.00% (15/25) as 42 genotype, 32.00% (8/25) as 43 genotype, and 8.00% (2/25) as 63 genotype, respectively. There were 7 genotypes in MLVA11 identified, with 116 genotype and 125 genotype the main genotypes, accounting for 56.00% (14/25) of all the identified strains.Conclusions:Genes from all the 25 strains of BM that isolated from human being were with high genetic diversities, and various, genotypes. However, no obvious epidemiological correlation was noticed among these strains, indicating the complexity of the source of infection on Brucella in Jiangxi province.

Objective:To compare the difference of pro-healing effect of porcine urinary bladder matrix (UBM) and porcine acellular dermal matrix (ADM) on full-thickness skin defect wounds in diabetic mice.Methods:Thirty-six type 2 diabetic BKS db/db mice aged 10 weeks were divided into UBM group and ADM group according to the random number table, with 18 mice in each group and preoperative molarity of non-fasting blood glucose higher than 16.6 mmol/L. A circular full-thickness skin defect wound with 6 mm in diameter was made on the back of each mouse, and porcine UBM and porcine ADM scaffolds were implanted into the wounds of both groups correspondingly. Immediately after operation and on post operation day (POD) 7, 14, and 28, wounds were observed generally. On POD 7, 14, and 28, 6 mice of each group were collected respectively to calculate the rate of wound epithelialization, and then the corresponding mice were sacrificed after calculation, and the wound tissue was harvested to make slices. Six slices of the mice in the 2 groups on POD 7 and 14 were respectively collected to stain with haematoxylin-eosin (HE), and 6 slices on POD 7 and 28 had Masson′s staining, which were used to observe histopathological changes and scaffold degradation. On POD 7 and 14, 24 slices of each mouse in the 2 groups were collected respectively to detect alpha smooth muscle actin (α-SMA) and CD31 positive expression denoting the growth of myofibroblasts and neovessels respectively and observe the distribution and activation of macrophages with immunohistochemical staining. The wound tissue of mice in the 2 groups on POD 7 and 14 was harvested to detect mRNA expressions of fibroblast growth factor 2 (FGF-2), vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF), and transforming growth factor β 1 (TGF-β 1) by real-time fluorescence quantitative reverse transcription polymerase chain reaction. The sample number of above-mentioned indexes in each group at each time point was 6. Data were statistically analyzed with analysis of variance for factorial design, t test, and Bonferroni correction. Results:(1) General observation showed that integration of UBM scaffold into the wounds of mice in UBM group on most time points was superior, and integration of ADM scaffold into the wounds of mice in ADM group on most time points was inferior. On POD 28, epidermis still did not form in some region of scaffold surface of wounds of mice in ADM group, while wounds of mice in UBM group were completely epithelialized. On POD 7, 14, and 28, wound epithelialization rates of mice in UBM group were respectively (22.4±6.4)%, (68.6±12.4)%, and 100.0%, all significantly higher than (4.5±2.2)%, (23.6±4.6)%, and (64.2±13.2)% in ADM group ( t=7.427, 9.665, 7.655, P<0.01). (2) HE staining and Masson′s staining showed that a large number of cells appeared in wound scaffold of mice in UBM group on POD 7; cells distributed in the whole region of UBM scaffold on POD 14; dermal tissue with structure similar to normal skin formed in the wounds and the fibrous morph of UBM scaffolds disappeared on POD 28. Only a small number of cells appeared in inside of wound scaffolds of mice in ADM group on POD 7; on POD 14, cells were sparsely distributed in ADM scaffolds; on POD 28, the morph of originally robust collagen fiber of ADM scaffolds was still clear and visible. (3) On POD 7, a large number of accumulated myofibroblasts and neovessels appeared in the lower layers of scaffolds of wounds of mice in UBM group; on POD 14, evenly distributed myofibroblasts and neovessels appeared in the upper layers of UBM scaffolds, and most vessels were perfused. On POD 7 and 14, myofibroblasts were sparsely distributed in scaffolds of wounds of mice in ADM group with no or a few neovascular structures perfused unobviously. On POD 7 and 14, α-SMA positive expressions in scaffolds of wounds of mice in UBM group were significantly higher than those in ADM group ( t=25.340, 6.651, P<0.01); CD31 positive expressions were also significantly higher than those in ADM group ( t=34.225, 10.581, P<0.01). (4) On POD 7, a large number of macrophages appeared in the lower layers of scaffolds of wounds of mice in UBM group; on POD 14, macrophages infiltrated into the internal region of UBM scaffolds, and M2 polarization occured without M1 polarization. On POD 7, a small number of macrophages appeared in the bottom of scaffolds of wounds of mice in ADM group; on POD 14, macrophages were few in internal region of ADM scaffold, and neither M2 polarization nor M1 polarization occurred. (5) On POD 7 and 14, mRNA expressions of FGF-2, VEGF, PDGF, and TGF-β 1 in the wound tissue of mice in UBM group were all significantly higher than those in ADM group ( t=7.007, 14.770, 10.670, 8.939; 7.174, 7.770, 4.374, 4.501, P<0.01). Conclusions:Porcine UBM scaffold is better than porcine ADM in facilitating wound repair and dermis reconstruction of full-thickness skin defects in diabetic mice through the induction of myofibroblasts and macrophages immigration, the promotion of neovascularization and expression of pro-healing growth factors.

Objective:To explore the clinical efficacy of different modes of continuous negative pressure wound therapy (NPWT) on venous ulcer wounds of lower limbs, and to analyze the influencing factors.Methods:From January 2018 to December 2019, 53 patients with venous ulcer of lower limbs who met the inclusion criteria and hospitalized in the Affiliated Hospital of Jiangnan University were recruited in this prospective randomized controlled study. According to the random number table, the patients were divided into single negative pressure therapy (SNPT) group (19 patients, 11 males and 8 females), cyclic alternating negative pressure therapy (CANPT) group (17 patients, 12 males and 5 females), and routine dressing change (RDC) group (17 patients, 10 males and 7 females), aged (47±11), (49±10), and (47±10) years respectively. After admission, patients in SNPT group were given continuous NPWT with the single negative pressure setting at -13.3 kPa, patients in CANPT group were also given continuous NPWT but with the cyclic alternating negative pressure setting from -16.0 to -10.7 kPa, while patients in RDC group were given dressing change with vaseline gauze soaked with iodophor. The wound healing rate was calculated on treatment day 7 and 14. Transcutaneous oxygen pressure (TcPO 2) around the wound was detected by TcPO 2 meter before treatment and on treatment day 7 and 14. The wound exudate/drainage fluid was collected on treatment day 1, 4, 7, 10, and 14, with the pH value measured using a pH meter, and the volume of exudate/drainage fluid recorded. Before treatment and on treatment day 7 and 14, venous blood was collected to detect the serum levels of interleukin 1β (IL-1β), IL-6, tumor necrosis factor α(TNF-α), transforming growth factor-β 1 (TGF-β 1), vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF). Before treatment and on treatment day 7 and 14, wound exudates were collected for bacterial culture, and Visual Analogue Scale and Hamilton Anxiety Scale were used to evaluate the degree of wound pain and anxiety of patients respectively. The length of hospital stay and the total treatment cost were counted. Analysis of variance for repeated measurement, one-way analysis of variance, least significant difference test, Kruskal Wallis H test, Mann Whitney U test, chi-square test, Fisher′s exact probability method test, and Bonferroni correction were used to analyze the data. According to the wound healing rate on treatment day 14, the efficiency of patients were divided into two grades of significant healing with wound healing rate≥70% and non significant healing with wound healing rate<70%. According to the two categories of wound healing rate as dependent variables, the levels of TcPO 2, IL-1β, IL-6, TNF-α, TGF-β 1, VEGF, bFGF levels and bacterial detection, wound pain and anxiety before treatment, wound exudate/drainage fluid volume and pH value on treatment day 1 were taken as covariates, and binary classification multifactor logistic regression analysis was used to analyze the risk factors of significant wound healing. Results:(1) On treatment day 7, the wound healing rate of patients in SNPT group was (33±10) %, which was significantly higher than (24±9) % of RDC group ( P<0.05). On treatment day 14, the wound healing rates of patients in SNPT group and CANPT group were (71±15)% and (66±18)%, respectively, which were significantly higher than (45±19)% of RDC group ( P<0.01). (2) Compared with those of RDC group, the TcPO 2 value around the wound of patients was significantly increased in SNPT group on treatment day 14 and in CANPT group on treatment day 7 and 14 ( P<0.05 or P<0.01), the pH value of wound drainage fluid of patients was significantly decreased in SNPT group on treatment day 10 and 14 and in CANPT group on treatment day 7 and 14 ( P<0.05), the volume of wound drainage fluid of patients was significantly reduced in SNPT group on treatment day 10 and 14 and in CANPT group on treatment day 7, 10, and 14 ( Z=-4.060, -4.954, -2.413, -4.085, -4.756, P<0.05 or P<0.01), the serum levels of IL-1β, IL-6, and TNF-α of patients were significantly decreased in SNPT group and CANPT group on treatment day 7 and 14 ( P<0.01), the serum level of TGF-β 1 of patients was significantly increased in CANPT group on treatment day 14 ( P<0.05), the serum levels of VEGF and bFGF were significantly increased in SNPT group and CANPT group on treatment day 14 ( P<0.01), the bacteria detection proportion of wound exudate, wound pain, and anxiety scores of patients were significantly decreased in SNPT group and CANPT group on treatment day 7 and 14 ( P<0.01). Compared between the negative pressure therapy two groups, except the wound pain score of patients in CANPT group was significantly lower than that in SNPT group ( P<0.01) on treatment day 7, the other indicators mentioned above were similar. (3) The length of hospital stay of patients in SNPT group was similar to that in CANPT group ( P>0.05), which were significantly shorter than the time in RDC group ( P<0.01). The total treatment cost of patients among the three groups was similar ( F=1.766, P>0.05). (4) Before treatment, the serum levels of TNF-α and bFGF, TcPO 2 around the wound, and the degree of wound pain were risk factors for significant wound healing (odds ratio=1.109, 0.950, 1.140, 2.169, 95% confidence interval=1.012-1.217, 0.912-0.988, 1.008-1.290, 1.288-3.651, P<0.05 or P<0.01). Conclusions:Clinical application of continuous NPWT under single negative pressure mode and cyclic alternating negative pressure mode has a positive effect on improving the wound base and healing rate of venous ulcer of lower limbs. But cyclic alternating negative pressure mode is significantly more effective than single negative pressure mode in improving TcPO 2 around the wound, reducing wound pH value, reducing exudate volume and relieving pain. The serum levels of TNF-α and bFGF, TcPO 2 around the wound and the degree of wound pain were the risk factors that affect the wound healing significantly.

Objective:To explore the effects of fractional carbon dioxide laser combined with autologous fat injection in the treatment of hypertrophic scar after burn.Methods:From April 2018 to April 2019, 12 patients with hypertrophic scar after burn who met the inclusion criteria were admitted to the Department of Plastic Surgery and Burns of Xuzhou Renci Hospital, and were included in this prospective parallel controlled clinical study. There were 7 males and 5 females with an age of (32±11) years old and scar area of (412±295) cm 2. One scar was selected from each patient and divided into two equal area scars, and they were divided into combined treatment group and laser alone group with 12 scars in each group according to the ramdom number table.The scar in laser alone group was only treated with fractiona carbon dioxide laser, while the scar in combined treatment group was injected with autologous granular fat and then treated with fractional carbon dioxide laser. Scars in the two groups were treated once every 2 months, a total of 3 times. Before the first treatment and 6 months after the last treatment, the scars in the two groups were evaluated by modified Vancouver Scar Assessment Scale (mVSS), hematoxylin-eosin staining and color Doppler ultrasound. Six months after the last treatment, the curative effect of scars in the two groups was evaluated. The adverse reactions during the whole treatment were recorded. Data were statistically analyzed with independent sample t test, paired sample t test, and McNemar exact probability method test. Results:Six months after the last treatment, the mVSS score of scars in combined treatment group was (4.5±0.4) points, which was significantly lower than (7.8 ±0.6) points in laser alone group ( t=10.000, P<0.01). Six months after the last treatment, the mVSS scores of scars in combined treatment group and laser alone group were significantly lower than those before the first treatment [(13.5±0.7) and (13.8±0.6) points, t=8.805, 9.010, P<0.01]. The effective number of scar treatment in combined treatment group was significantly more than that in laser alone group ( P<0.05). There was no scar aggravation, infection, or other adverse reactions during the treatment of scars in both groups. Before the first treatment, the scars in both groups had large collagen, disordered arrangement, proliferation of capillaries, infiltration of some inflammatory cells, and disappearance of skin appendages. Six months after the last treatment, the scar collagen in both groups was sparse and orderly arranged, and the vascular density was reduced. The improvement of scars in combined treatment group was more obvious than that of laser alone group. Six months after the last treatment, the scar thickness in combined treatment group was significantly smaller than that in laser alone group ( t=2.657, P<0.05). Before the first treatment, the blood flow of scars in both groups was abundant; 6 months of the last treatment, the blood flow of scars in combined treatment group was significantly less than that in laser alone group. Conclusions:Fractional carbon dioxide laser combined with autologous fat injection in the treatment of hypertrophic scar after burn can significantly reduce the pain and itching symptoms of scar, and improve the thickness, texture, and congestion of scar. The combined treatment has synergistic effect and less adverse reactions, which provides a more effective treatment for patients with hypertrophic scar.