[Expressions and effects of autophagy-related genes in bleomycin-induced skin fibrosis of mice]

Objective: To investigate the expressions and effects of autophagy-related genes in bleomycin-induced skin fibrosis of mice. Methods: (1) Totally 72 male BALB/c mice aged 6 weeks were divided into blank control group, simple phosphate buffer solution (PBS) group, and bleomycin group according to the random number table, with 24 mice in each group. Mice in blank control group received no treatment, and 100 μL of PBS and bleomycin (1 mg/mL) were respectively injected subcutaneously in the back skin of mice in simple PBS and bleomycin group, once a day for 28 days. On injection day (ID) 7, 14, 21, and 28, 6 mice in each group were collected to observe the skin change on the back of mice with naked eyes. After the observation, the mice were sacrificed and skin tissue on the back was taken. Skin tissue of mice on ID 28 was collected to measure the thickness of skin tissue by routine hematoxylin-eosin staining and observe skin tissue morphology by Masson staining. Skin tissue on ID 7, 14, 21, and 28 was taken to detect content of hydroxyproline by enzyme linked immunosorbent assay, and mRNA and protein expressions of p62, microtubule-associated protein 1 light chain 3 Ⅱ (LC3 Ⅱ) and Beclin-1 were detected by real-time fluorescent quantitative reverse transcription polymerase chain reaction and Western blotting, respectively. (2) Skin tissue of mice in blank control group in experiment (1) was taken to culture fibroblasts (Fbs) in 3rd-6th passages. The cells were divided into blank control group, simple PBS group, and bleomycin group according to the random number table, with 6 wells in each group. Cells in blank control group were not stimulated, and cells in simple PBS group and bleomycin group were stimulated with 20 μL of PBS and bleomycin (1 mg/mL) for 72 h, respectively. Cellular immunofluorescence staining was used to observe the expression of LC3 Ⅱ. Data were statistically analyzed with analysis of variance of factorial design, one-way analysis of variance, t test, and Bonferroni correction. Results: (1) Skin on the back of mice in blank control group and simple PBS group was thin and ruddy, and the veins were clear on ID 7, 14, 21, and 28. Several raised ridges were visible on the puncture site of mice in simple PBS group from ID 14. Skin on the back of mice was ruddy, with several raised ridges visible on the puncture site of mice in bleomycin group on ID 7, the skin turned slightly white on ID 14, the skin turned white obviously with unclear surrounding blood vessels on ID 21, and the skin turned white and the surrounding blood vessels could not be recognized on ID 28. (2) On ID 28, the skin thicknesses of mice in blank control group and simple PBS group were similar (t=0.79, P>0.05). Compared with that in blank control group and simple PBS group, the skin thickness of mice in bleomycin group was significantly increased (t=0.50, 0.50, P<0.01). (3) On ID 28, the skin tissue structure of mice in blank control group and simple PBS group was similar, with a small amount of orderly arranged collagen and evenly distributed hair follicle; the number of collagen of skin in mice of bleomycin group was increased obviously and arranged disorderly, and the number of hair follicle was decreased significantly. (4) On ID 7, 14, 21, and 28, the content of hydroxyproline in the skin tissue of mice in bleomycin group was significantly higher than that in blank control group and simple PBS group (t=0.99, 0.98, 0.50, 0.51, 0.50, 0.50, 0.52, 0.51, P<0.05 or P<0.01). (5) On ID 7, p62 mRNA expression in the skin tissue of mice in bleomycin group was significantly lower than that in simple PBS group (t=0.93, P<0.05). On ID 14 and 21, the mRNA expressions of p62, LC3 Ⅱ, and Beclin-1 in the skin tissue of mice in bleomycin group were significantly higher than those in blank control group (t=0.74, 0.70, 0.58, 0.49, 0.51, 0.74, P<0.05) and simple PBS group (t=0.94, 0.65, 0.65, 0.77, 0.49, 0.51, P<0.05). On ID 28, the mRNA expressions of p62 and Beclin-1 in the skin tissue of mice in bleomycin group were significantly lower than those in blank control group (t=0.50, 0.44, P<0.05) and simple PBS group (t=0.97, 0.55, P<0.05), and that of LC3 Ⅱ was significantly higher than that in blank control group and simple PBS group, respectively (t=0.51, 0.98, P <0.01). (6) On ID 7, 14, 21, and 28, the protein expressions of LC3 Ⅱ in blank control group, simple PBS group, and bleomycin group were 0.167±0.042, 0.122±0.016, 0.553±0.078, 0.118±0.035, 0.120±0.023, 0.117±0.061, 0.581±0.039, 0.159±0.065, 0.233±0.027, 0.304±0.031, 1.020±0.010, 0.089±0.045. On ID 14, the protein expressions of p62 and Beclin-1 in the skin tissue of mice in bleomycin group were significantly higher than those in blank control group (t=0.86, 0.89, P<0.05) and simple PBS group (t=0.42, 0.89, P<0.05). On ID 21, the protein expressions of p62, LC3 Ⅱ, and Beclin-1 in the skin tissue of mice in bleomycin group were significantly higher than those in blank control group and simple PBS group (t=0.82, 0.45, 0.50, 0.79, 0.51, 0.50, P<0.01). On ID 28, the protein expressions of p62, LC3 Ⅱ, and Beclin-1 in the skin tissue of mice in bleomycin group were significantly lower than those in blank control group and simple PBS group (t=0.77, 0.54, 0.52, 0.50, 0.51, 0.50, P<0.05). (7) After culture for 72 h, the expression of LC3 Ⅱ in Fbs of bleomycin group was significantly lower than that of blank control group and simple PBS group, respectively. Conclusions: In the process of bleomycin stimulating skin fibrosis, autophagy-related genes increase firstly and then decrease. When the autophagy process is activated, it is expected to reverse the process of skin fibrosis.

[Effects of anterolateral thigh free flap with fascia lata in repairing dura mater defect after resection of head squamous cell carcinoma]

Objective: To evaluate the clinical effects of anterolateral thigh free flap with fascia lata in the repair of dura mater defect after resection of head squamous cell carcinoma. Methods: From June 2016 to June 2018, Xijing Hospital of Air Force Medical University applied the free transplantation of anterolateral thigh flap with fascia lata to repair the dura mater defect of 12 patients with head squamous cell carcinoma, including 9 males and 3 females, aged from 35 to 74 years. The size of scalp soft tissue defects in patients after carcinoma resection ranged from 12 cm×10 cm to 24 cm×21 cm, and the size of dura mater defect of patients ranged from 7 cm×6 cm to 16 cm×14 cm. The size of flap of patients ranged from 14 cm×12 cm to 27 cm×24 cm, and the size of fascia lata ranged from 8 cm×7 cm to 17 cm×15 cm. The superficial temporal artery and middle temporal vein were connected by end to end anastomosis with the first musculocutaneous perforating branch of the descending branch of lateral femoral artery and its accompanying vein. The flap donor area was transplanted with autologous split-thickness skin graft from trunk and fixed with packing. Postoperative survival of flaps and skin grafts was observed. The patients were followed up regularly. The cranial magnetic resonance imaging was performed to observe the recurrence of intracranial tumors and dural integrity, shape of the flap and whether the donor site region was left with significant dysfunction were observed. Results: All the flaps and skin grafts survived well in 12 patients after surgery. Ten patients had primary healing at the edge of the flap suture; 2 patients had local sinus tract formation at the suture site of flap, with a small amount of cerebrospinal fluid leakage, and were recovered after outpatient dressing change. The patients were followed up for 10 to 36 months, and 3 patients with tumors involving in the dura mater sagittal sinus region had postoperative intracranial tumor recurrence. The tumor was resected again. All the patients had good dural integrity. The flaps of all patients were in good shape, and no obvious dysfunction remained in the flap donor site. Conclusions: Free transplantation of anterolateral thigh flap with fascia lata is an effective and reliable method to repair the dura mater defect following head squamous cell carcinoma resection. It can repair the scalp and dura mater defects caused by the invasion of squamous cell carcinoma and provide possibilities for skull reconstruction.

[Effect of silent information regulator 1 on the LPS induced lncRNA expression of macrophages in mice]

Objective: To investigate the effect of Silent information regulator 1 (Sirt1) on the expression profile of long non-coding RNA (lncRNA) in macrophages upon lipopolysaccharide (LPS) treatment. Methods: Peritoneal macrophages (PM) were isolated from nine wild-type C57BL/6 male mice (wild-type group) and nine myeloid-specific Sirt1 knock-out mice (knock-out group). RNA samples were extracted from macrophages stimulated with 1 μg/ml LPS. Sequencing and the differentially expressed lncRNA were screened after the RNA was quantified. The threshold set for up-and down-regulated genes was a fold change (wild-type group/knock-out group) ≥2 and P≤0.05. Afterwards, gene ontology (GO) and pathway enrichment analysis were conducted and co-expression network map was constructed. Results: Four hundred and forty five lncRNA genes were differentially expressed (185 lncRNA genes were up-regulated and 260 lncRNA genes were down-regulated). Two hundred mRNA genes were differentially expressed (113 mRNA genes were up-regulated and 87 mRNA genes were down-regulated). It was found that the differentially expressed lncRNA genes and the predicted corresponding target genes were mainly distributed in the regions of biological processes of macrophage inflammatory response, macrophage chemotaxis and cell metabolism by GO and pathway enrichment analysis. Conclusion: lncRNA expression profile changes significantly in LPS induced macrophages isolated from Sirt1 knock out mice, which is closely related to the function of macrophages.

[Advances in the research of poststernotomy dehiscence and repair with tissue flap transplantation]

Sternotomy is a routine surgical pathway for heart, lung, and mediastinal surgery. Poststernotomy dehiscence is a common complication of sternotomy, in which infection after poststernotomy dehiscence is one of the most serious postoperative complications in cardiothoracic surgery. Previously, conventional dressing, negative pressure wound therapy, and skin stretching device were used in the treatment of poststernotomy dehiscence, but the outcome of each single method was poor, which caused great pain and burden to the patients and their families. In recent years, tissue flap containing rich blood supply has drawn a lot of attention because of its good wound cover, stable thoracic reconstruction, low infection recurrence rate, and less postoperative complication. In this paper, we reviewed the epidemiological characteristics of poststernotomy dehiscence, and summarized the various classifications for poststernotomy dehiscence and the therapeutic effects of different tissue flap repair. We hope that this review would provide a basis for further construction of the treatment system for poststernotomy dehiscence and the formation of a treatment guideline.

[Application of low temperature thermoplastic plate combined with special abdominal band in fixing abdominal pedicled flap for repairing 17 patients with deep electric burn wounds in hands]

If the abdominal pedicled flaps are not well fixed after repair of deep electric burn wounds in hands, many problems such as poor blood supply may occur. In order to solve the above problems, we designed and manufactured the individualized low temperature thermoplastic plate combined with special abdominal band to fix abdominal pedicled flaps for repairing of 17 patients (12 males and 5 females, aged 2-35 years) with deep electric burn wounds in hands from February 2016 to August 2018, and achieved the desired results. The shoulder joint, elbow joint, and wrist joint were fixed by low temperature thermoplastic plate according to the 1/2 circumference of the patient's side chest and upper arm, and the braking of wrist joint and elbow joint was strengthened by special abdominal band. Application of the combined method of fixing abdominal pedicled flaps in repairing deep electric burn wounds in hands has high success rate of flap transplantation. It is simple to make and practical, and worthy of clinical promotion.

[Application of adipose stem cells in tissue repair and reconstruction]

Adipose stem cells (ASCs) are mesenchymal stem cells derived from adipose tissue, and they have potentials of self-renewal and multi-directional differentiation. Compared with bone marrow mesenchymal stem cells, ASCs have many advantages, such as easy access, easy cultivation, and abundant content, which are valuable seed cells in the field of repair and reconstruction. In recent years, with the deepening of the researches on differentiation, regulation, and function of ASCs, the clinical application of ASCs has gradually increased with good therapeutic effects.

[Analysis of influencing factors on hepatic encephalopathy in patients with non-cirrhotic portal hypertension]

Objective: To investigate the incidence of hepatic encephalopathy (HE) in patients with non-cirrhotic portal hypertension (NCPH) and to explore its risk factors. Methods: The incidence rate of HE in 150 cases with NCPH was evaluated in two hospitals, and 188 cases of compensated cirrhosis patients were taken as control. Logistic regression was used to screen for independent risk factors for HE in patients with NCPH. Results: The incidence of overt hepatic encephalopathy (OHE) in patients with NCPH was not statistically significantly different from that in patients with cirrhosis (4.7% vs. 6.9%, P = 0.682). The incidence of mild hepatic encephalopathy (MHE) was significantly lower than that of cirrhosis patients (32.7% vs. 46.3%, P < 0.05). The presence of upper gastrointestinal bleeding, infection and portosystemic venous shunt were the main independent factors for HE in NCPH patients (OR > 1, P < 0.05). Conclusion: HE is one of the important complications of NCP, and may be influenced by factors such as upper gastrointestinal bleeding, infection and portosystemic venous shunt.

[Observation on the effects of multidisciplinary comprehensive intervention in integrated treatment of patients with extremely severe burns]

Objective: To explore the effects of multidisciplinary comprehensive intervention in integrated treatment of patients with extremely severe burns. Methods: One hundred and ten patients hospitalized in our center from July 2013 to August 2017 met the criteria for inclusion in this study, and their medical records were retrospectively analyzed. According to the medical model at that time, 56 patients hospitalized from July 2013 to July 2015 received routine comprehensive treatment led by doctors, and they were included in the conventional intervention group. From August 2015 to August 2017, 54 patients were treated with integrated multidisciplinary interventions performed by a team consisting of physicians, intensive care nurses, burn nurses, intravenous infusion nurses, wound stoma nurses, and rehabilitation therapists, and they were included in the integrated intervention group. Acute Physiological and Chronic Health Assessment Ⅱ (APACHE Ⅱ) scores on admission and 4 weeks after treatment, incidences of pressure injury, wound sepsis, lung infection, and catheter-related infection during hospitalization, length of stay in intensive care unit (ICU) and total length of hospital stay, and Abbreviated Burn Specific Health Scale (BSHS-A) scores at discharge and 3 months after discharge were analyzed. Data were processed with t-test and chi-square test. Results: The APACHE Ⅱ scores of patients in the two groups were close on admission (t=0.573, P>0.05). Four weeks after treatment, the APACHE Ⅱ scores of patients in the two groups were obviously lower than those on admission within the same group (t=5.697, 4.853, P<0.01), and the score of the integrated intervention group was obviously lower than that of the conventional intervention group (t=2.170, P<0.05). No pressure injury was observed in patients of any group during hospitalization. The incidences of wound sepsis, lung infection, and catheter-related infection of patients in the integrated intervention group were 18.5% (10/54), 3.7% (2/54), and 9.3% (5/54), respectively, significantly lower than 42.9% (24/56), 21.4% (12/56), and 26.8% (15/56) of the conventional intervention group, χ²=4.073, 6.075, 3.962, P<0.05. The length of stay in ICU of patients in the integrated intervention group was (50±5) d, obviously shorter than (62±4) d of the conventional intervention group (t=2.852, P<0.01). The total length of hospital stay of patients in the integrated intervention group was (115±8) d, obviously shorter than (140±7) d of the conventional intervention group (t=16.885, P<0.01). At discharge and 3 months after discharge, the scores of BSHS-A, physical function, psychological function, and general health status of 50 patients in the integrated intervention group were significantly higher than those of 48 patients in the conventional intervention group (t=2.886, 3.126, 2.416, 2.544, 2.033, 3.471, 2.588, 2.210, P<0.05 or P<0.01), while the scores of social function of patients in the two groups were close (t=1.570, 1.350, P>0.05). Conclusions: Integrative treatment of patients with extremely severe burns by multidisciplinary comprehensive intervention can significantly alleviate the severity of burns, reduce the incidences of wound sepsis, lung infection, and catheter-related infection, shorten the length of stay in ICU and total length of hospital stay, and improve the quality of life.

[Clinical comparative study of pulsed dye laser and ultra-pulsed fractional carbon dioxide laser in the treatment of hypertrophic scars after burns]

Objective: To compare the efficacy and safety of pulsed dye laser (PDL) and ultra-pulsed fractional carbon dioxide laser (UFCL) in treating hypertrophic scars after burns. Methods: Two hundred and twenty one patients with hypertrophic scar after burns conforming to the study criteria were admitted to our unit from February 2015 to October 2017, and their data were retrospectively analyzed. Patients were divided into group PDL (n=122) and group UFCL (n=99) according to the treatment method. Patients in group PDL were treated with PDL once every 3-4 weeks. Patients in group UFCL were treated with UFCL once every 6-12 weeks. Patients in both groups were treated until 12 months after having scar. Scars were scored by Vancouver Scar Scale (VSS) before and after treatment. Patients' pain was evaluated by Visual Analogue Scale (VAS) method before and after treatment. Blood flow in scar was monitored and recorded before treatment and in treatment months 6 and 12. Satisfaction degree of patients was recorded 3-6 months after treatment, and the satisfaction rate was calculated. Adverse reactions including duration of erythema/purpura, VAS in treatment, and loss of working time were recorded. Data were processed with one-way analysis of variance, t test, and Chi-square test. Results: (1) VSS scores of patients in groups PDL and UFCL after treatment were significantly lower than those before treatment in the same group (t=11.34, 12.77, P<0.05). The decreasing VSS scores of patients after treatment in groups PDL and UFCL were (5.8±1.1) and (6.0±1.4) points, respectively, and there was no statistically significant difference between the two groups (t=1.91, P>0.05). (2) VAS of patients in groups PDL and UFCL after treatment were significantly lower than those before treatment in the same group (t=7.12, 5.23, P<0.05). The decreasing VAS of patients after treatment in groups PDL and UFCL were (4.0±0.6) and (3.2±1.3) points, respectively, and there was no statistically significant difference between the two groups (t=1.93, P>0.05). (3) Scar blood flow of patients in group PDL in treatment months 6 had no obvious change compared with that before treatment (t=1.59, P>0.05), while that in treatment months 12 significantly decreased compared with that before treatment and that in treatment months 6 (t=3.17, 6.96, P<0.05). Scar blood flow of patients in group UFCL in treatment months 6 significantly increased compared with that before treatment (t=6.01, P<0.05), while that in treatment months 12 significantly decreased compared with that in treatment months 6 (t=4.52, P<0.05), but had no obvious change compared with that before treatment (t=0.92, P>0.05). (4) The satisfaction degree of patients in group PDL was 80.3% (98/122), which in group UFCL was 76.8% (76/99), and there was no statistically significant difference between the two groups (χ(2)=0.97, P>0.05). (5) The duration of erythema/purpura of patients in group PDL was (5.2±0.7) d, significantly shorter than (6.1±0.5) d in group UFCL (t=2.49, P<0.05). The VAS of patients in group PDL during treatment was (1.9±0.9) points, significantly lower than (4.7±0.4) points in group UFCL (t=4.85, P<0.05). Loss of working time of patients in group UFCL was (9.17±0.72) d, which was significantly longer than (3.96±0.23) d in group PDL (t=3.17, P<0.05). Conclusions: PDL and UFCL have definite effects on hypertrophic scar, while PDL with light pain, minor wound, and fast recovery time, is safe and effective for treatment of early hypertrophic scar and worthy of clinical promotion and application, especially for children and patients with poor pain tolerance.

[Effects of free superficial temporal fascia flaps and skin grafts in repairing deep wounds in posterior ankle region of extensively burned patients]

Objective: To observe the effects of the method of combining free superficial temporal fascia flaps with skin grafts in repairing deep wounds in posterior ankle region of extensively burned patients. Methods: From September 2013 to February 2017, 11 extensively burned patients with deep tissue defects in posterior ankle region were treated in our unit. Two patients had tissue defects in bilateral posterior ankle regions. The wound sizes ranged from 5.8 cm×4.6 cm to 11.7 cm×5.2 cm. Free superficial temporal fascia flaps with the same sizes as the wounds were designed and resected to repair wounds in posterior ankle regions after debridement. The proximal end of superficial temporal veins and posterior tibial veins were performed with end-to-end anastomosis, and superficial temporal arteries and posterior tibial arteries were performed with end-to-side anastomosis. Skin grafts were resected to cover the superficial temporal fascia flaps according to patients' condition of donor sites. The donor sites were sutured directly. Results: All fascial flaps in 11 patients survived, while 2 skin grafts had partial necrosis, and they healed after secondary skin graft. All patients were followed up for 6 to 13 months, and the shape and function of the operation sites in all patients recovered well. Conclusions: The method of combining free superficial temporal fascia flaps with skin grafts can repair deep wounds in posterior ankle regions of extensively burned patients. It has the advantages of good appearances in the recipient sites, strong resistances to infection of fascia flaps, minimal damages to the donor sites, short course of disease, and good prognosis of patients.

[Clinical efficacy observation on combination of narrow-spectrum medium-wave ultraviolet, red light, and low power He-Ne laser in treating post-burn eczema]

Objective: To investigate the clinical effects of combined utilization of narrow-spectrum medium-wave ultraviolet, red light, and low power He-Ne laser on treatment of post-burn eczema. Methods: From July 2014 to July 2017, 80 patients with post-burn eczema who met the study inclusion criteria were treated in our burn rehabilitation center, and their clinical data were analyzed retrospectively. Patients were divided into ultraviolet treatment group, red light treatment group, laser treatment group, and combination treatment group according to the utilized treatment methods, with 20 cases in each group. Patients in ultraviolet treatment group were treated with narrow-spectrum medium-wave ultraviolet once every other day for 10 minutes each time. Patients in red light treatment group and laser treatment group were treated with red-light and low power He-Ne laser respectively once a day for 10 minutes each time. Patients in combination treatment group were treated with combination of the above three methods without sequence or interval time, and the treatment time and interval time were the same as the previously described. All patients were treated for four weeks since the time of admission. The itching degree, surface area of the affected body, degree of keratosis, and degree of cracking of target tissue were evaluated using Eczema Area and Severity Index (EASI) scoring method after each treatment. Eczema improvement rate was calculated according to the total score of EASI to determine the curative effect. The therapeutic effective time was recorded. The therapeutic effective rate was calculated according to the total scores of EASI before treatment for the first time and 4 weeks after treatment. Besides, the adverse reactions of patients were also observed and recorded. Data were analyzed by Chi-square test, Kruskal-Wallis rank sum test, Wilcoxon signed rank sum test, one-way analysis of variance, Least Significant Difference-t test, and Bonferroni correction. Results: Therapeutic effective times of eczema of patients in ultraviolet treatment group, red light treatment group, and laser treatment group were similar, respectively (13.7±1.3), (16.4±1.6), and (15.1±1.7) d (t=0.32, 0.58, 0.74, P>0.05). The therapeutic effective time of combination treatment group was (6.3±0.9) d, significantly shorter than that of ultraviolet treatment group, red light treatment group, or laser treatment group (t=5.62, 4.72, 4.61, P<0.05 or P<0.01). Compared with those before treatment for the first time, eczema itching degree, surface area of affected body, degree of keratosis, degree of cracking, and total score of EASI of patients in ultraviolet treatment group, red light treatment group, laser treatment group, and combination treatment group showed obvious improvement in 4 weeks after treatment (Z=5.372, 4.392, 4.284, 3.998, 4.092, 3.904, 4.042, 4.216, 3.684, 3.890, 5.081, 4.794, 4.094, 3.493, 3.995, 5.084, 4.903, 4.384, 3.995, 4.063, P<0.05 or P<0.01). Each item score and total score of EASI of eczema of patients in the first three groups were close (P>0.05), while each item score and total score of EASI of eczema of patients in combination treatment group was significantly better than those of ultraviolet treatment group, red light treatment group, and laser treatment group (H=2.482, 2.491, 3.583, 3.462, 6.025, 2.492, 3.693, 3.085, 3.482, 6.042, 5.831, 5.831, 4.893, 4.092, 6.931, P<0.05). Therapeutic effective rates of eczema of patients in ultraviolet treatment group, red light treatment group, and laser treatment group were close, respectively 60%, 60%, and 55% (χ(2)=1.46, 1.63, 0.97, P>0.05). The therapeutic effective rate of eczema of patients in combination treatment group was 90%, significantly higher than that of ultraviolet treatment group, red light treatment group, or laser treatment group (χ(2)=3.43, 4.15, 2.97, P<0.05 or P<0.01). There were no serious adverse reactions appeared in patients of all the four groups after treatment. Three patients in ultraviolet treatment group had local skin erythema, which was alleviated after symptomatic treatment. Conclusions: Combination of narrow-spectrum medium-wave ultraviolet, red light, and low power He-Ne laser in treating post-burn eczema is superior to single therapy in terms of clinical effective time and efficacy, which has no obvious adverse reaction and is worthy of promotion.

[Strategy for wound repair of skin and soft tissue defect and systematic rehabilitation treatment for functional reconstruction of patients with severe burn or trauma on knees]

Objective: Strategy for wound repair of skin and soft tissue defect and systematic rehabilitation treatment for functional reconstruction of patients with severe burn or trauma on knees. Methods: From January 2015 to October 2016, 26 patients with skin and soft tissue defect on knees after severe burn or trauma were hospitalized in our unit. Among these patients, 14 patients had patellar ligament defect, and 16 patients had knee joint capsule defect. Wound debridement was operated on 1 to 3 days after admission. After debridement, the area of skin and soft tissue defect ranged from 10 cm×7 cm to 42 cm×18 cm. Vacuum sealing drainage (VSD) treatment was performed after debridement, and flap transplantation operation was performed after VSD treatment for 5 to 7 days. Defects of nine patients were treated with local rotation flaps. Seven patients with skin and soft tissue defects on knees and knee joint capsule defects of 5 cm×3 cm to 9 cm×7 cm were treated with free anterolateral femoral flaps combined with fascia lata. Ten patients with skin and soft tissue defects on knees and patellar ligament defects of 6 cm×3 cm to 12 cm×4 cm were treated with free anterolateral femoral flaps combined with iliotibial tract. The area of flaps ranged from 11 cm×9 cm to 22 cm×15 cm. After flap transplantation operation, functional reconstruction of knee joint was carried out according to early, continuous, and sequential systematic rehabilitation treatment strategy. The pain degree and function of knee joint of patients were scored by the International Knee Documentation Committee (IKDC) Knee Evaluation Form before operation and 12 months after operation. The knee joint flexion and extension degrees of patients were measured by joint protractor in 2 weeks and 12 months after operation. The color Doppler ultrasound was used to evaluate integrity of knee joint capsule and continuity of patellar ligament of patients in 6 and 12 months after operation. Results: All flaps of 26 patients survived well, and wounds healed completely after the operation. Distal parts of flaps of 2 patients treated with free anterolateral femoral flaps had local necrosis after the operation, and their wounds healed after debridement and transplantation of autologous intermediate split-thickness skin graft of thigh. The IKDC Knee Evaluation Form score of patients was (79±8) points in 12 months after operation, which was significantly higher than (64±7) points before operation (t=7.20, P<0.05). The flexion degree of knee joint of patients was (117±10)° in 12 months after operation, which was significantly larger than (35±8)° in 2 weeks after operation (t=32.65, P<0.05). The extension degree of knee joint of patients was (12±9)° in 12 months after operation, which was significantly smaller than (61±9)° in 2 weeks after operation (t=19.63, P<0.05). In 6 and 12 months after operation, 9 patients treated with local rotation flaps had good integrity of knee joint capsule and continuity of patellar ligament; 7 patients treated with free anterolateral femoral flaps and fascia lata had good integrity of knee joint capsule; 10 patients treated with free anterolateral femoral flaps and iliotibial tract had good continuity of patellar ligament. During follow-up of 12 months, all flaps survived well; knees of all patients had good appearance; knee joints functioned normally. Conclusions: Good appearance and function of knees can be achieved by repairing wound of skin and soft tissue defect on knees after severe burn or trauma with local rotation flaps or free anterolateral femoral flaps with fascia lata or iliotibial tract plus systematic rehabilitation treatment of knee joint in early stage after flap transplantation operation.

[Effects of microRNA-34a on regulating silent information regulator 1 and influence of the factor on myocardial damage of rats with severe burns at early stage]

Objective: To explore the effects of microRNA-34a on regulating silent information regulator 1 (SIRT1) and influence of SIRT1 on myocardial damage of rats with severe burns at early stage. Methods: (1) Twenty-four Sprague-Dawley (SD) rats were divided into sham injury (SI) group, simple burns (SB) group and SIRT1 agonist (SA) group according to the random number table (the same grouping method below), with 8 rats in each group. Rats in groups SB and SA were inflicted with 30% total body surface area full-thickness scald (hereinafter referred to as burns) on the back, and rats in group SI were sham injuried on the back. Immediately after injury, rats in groups SI and SB were intraperitoneally injected with normal saline of 50 mL/kg, and rats in group SA were intraperitoneally injected with normal saline of 50 mL/kg and 1 mg/mL resveratrol of 50 mg/kg. At 6 h post injury, abdominal aortic blood was collected to make serum and myocardial tissue of rats was collected. (2) Myocardial cells of twelve neonatal SD rats were collected and divided into microRNA-34a mimic control (MMC) group, microRNA-34a mimic (MM) group, microRNA-34a inhibitor control (MIC) group, and microRNA-34a inhibitor (MI) group, which were respectively transfected with gene sequences of mimic control, mimic, inhibitor control, and inhibitor of microRNA-34a. The microRNA-34a expression level and protein expression level of SIRT1 in myocardial cells were respectively detected by real-time fluorescence quantitative reverse transcription polymerase chain reaction (RT-PCR) and Western blotting. Another batch of myocardial cells were divided into microRNA-34a inhibitor control+ burn serum (MCB) group, microRNA-34a inhibitor+ burn serum (MB) group, and microRNA-34a inhibitor+ burn serum + EX527 (MBE) group. Myocardial cells in group MCB were transfected with gene sequence of inhibitor control, and myocardial cells in the later groups were transfected with gene sequence of inhibitor of microRNA-34a. After transfection of 48 h, myocardial cells in group MBE were cultured in Dulbecco's modified Eagle's medium (DMEM) solution for 6 hours, with serum in group SB of volume fraction of 10% and final amount-of-substance concentration of 1 mol/L, and myocardial cells in the other 2 groups were cultured in DMEM solution with serum from rats of group SB of volume fraction of 10%. The protein expression levels of myocardial cells of SIRT1, cleaved-caspase-3, and Bax were detected by Western blotting. (3) Myocardial tissue from (1) was collected to detect expression levels of microRNA-34a and mRNA of SIRT1 in groups SI and SB by real-time fluorescence quantitative RT-PCR. Morphology of myocardial tissue of rats in groups SI, SB, and SA was observed with biological image navigator. The mRNA expression levels of interleukin 1β (IL-1β) and tumor necrosis factor (TNF-α) of rats in groups SI, SB, and SA were detected by real-time fluorescence quantitative RT-PCR. The expression levels of cleaved-caspase-3, and Bax of myocardial tissue of rats in groups SI, SB, and SA were detected by Western blotting. Data were processed with one-way analysis of variance and least-significant difference test. Results: (1) After transfection of 48 h, the expression level of microRNA-34a of myocardial cells in group MM was 4.67±0.92, significantly higher than 1.03±0.04 in group MMC (P<0.01); the protein expression level of SIRT1 of myocardial cells in group MM was 0.35±0.06, significantly lower than 1.12±0.11 in group MMC (P<0.01). After transfection of 48 h, the expression level of microRNA-34a of myocardial cells in group MI was 0.26±0.07, significantly lower than 1.33±0.07 in group MIC (P<0.01); the protein expression level of SIRT1 of myocardial cells in group MIC was 1.12±0.16, significantly lower than 1.74±0.34 in group MI (P<0.01). At 6 h after culture, compared with those in group MCB, the SIRT1 protein expression level of myocardial cells in group MB was significantly increased (P<0.05), while cleaved-caspase-3 and Bax protein expression levels of myocardial cells in group MB were significantly decreased (P<0.05). Compared with those in group MB, the SIRT1 protein expression level of myocardial cells in group MBE was with no significantly statistical difference (P>0.05), and cleaved-caspase-3 and Bax protein expression levels were significantly increased (P<0.05). (2) At 6 h post injury, compared with that in group SI, the microRNA-34a expression level of myocardial tissue in group SB was significantly increased (P<0.01), and the mRNA expression level of SIRT1 of myocardial tissue in group SB was significantly decreased (P<0.01). At 6 h post injury, myocardial cells in group SI arranged neatly with normal nucleus and no inflammatory cells infiltration; myocardial cells in group SB arranged disorderly, with no abnormal nucleus, and obvious inflammatory cells infiltration; myocardial cells in group SA arranged neatly, with normal nucleus and little inflammatory cells infiltration. At 6 h post injury, compared with those in group SB, the mRNA expression levels of IL-1β and TNF-α, and the protein expression levels of cleaved-caspase-3 and Bax of myocardial tissue in groups SI and SA were significantly decreased (P<0.01). Conclusions: The microRNA-34a expression level of myocardial tissue of rats with severe burns at early stage increases, which decreases the expression level of SIRT1, and increases the expression levels of IL-1β, TNF-α, cleaved-caspase-3 and Bax, leading to obvious myocardial damage. Activation of SIRT1 can alleviate myocardial damage of rats with severe burns at early stage through decreasing expression levels of IL-1β, TNF-α, cleaved-caspase-3, and Bax.

[A retrospective study of tumor and fertility outcomes after fertility-sparing surgical treatment of patients with borderline ovarian tumors]

Objective: To study tumors and fertility outcomes after fertility-sparing surgical treatment with borderline ovarian tumors (BOT). Methods: One hundred and nineteen patients with BOT enrolled from 3 hospitals between January 2004 and January 2017 were analysed retrospectively.The clinical data and follow-up results were obtained and analyzed. Results: Among the 119 BOT patients, 55 patients underwent fertility-sparing surgery.The median age was 43 years (interquartile range: 15-80 years). There were 103 patients (86.55%) in stage Ⅰ, and 16 patients (13.45%) in stage Ⅱ and above.The median follow up time was 68 months (range: 4-155). (1)Tumor outcomes: 13 patients recurred and 3 patients died.Progression free survival (PFS) and the overall survival rate had no significant difference between the two groups (85.45% vs 92.19% P=0.309, 96.4% vs 98.4% P=0.492). PFS was related to FIGO stage, invasive implantation and chemotherapy by univariate analysis (P<0.05). The multivariate Cox regression model analysis showed that FIGO stage and invasive implantation were independent prognostic factors for PFS (P<0.05). (2) Pregnancy outcomes: 28 patients had a planned for pregnancy in fertility-sparing group, with 13 (46.43%) of them were pregnancy. Conclusions: FIGO stage and invasive implantation were the important factors of prognosis.Fertility-sparing surgery is safe and feasible to preserve the fertility of young patients.

[Advances in the research of molecular mechanism of negative pressure wound therapy in improving wound healing]

Recently, negative pressure wound therapy (NPWT) is a rising technology to improve wound healing. In clinical application, it benefits fast debridement and wound close, limits infection, and promotes wound healing. It is an effective therapy for all kinds of acute or chronic wound. Currently, researches demonstrate that NPWT promotes angiogenesis, granulation tissue growth, and extracellular matrix remodeling through regulating the signaling of anti-inflammatory cytokines, mechanicalreceptor and chemoreceptor, which is related to several growth factors and inflammatory factors. Here we focus on the recent advances in the mechanism of NPWT in promoting wound healing, looking forward to providing a review of NPWT and related researches.

[Effects of human amniotic epithelial stem cells-derived exosomes on healing of wound with full-thickness skin defect in rats]

Objective: To investigate the effects of human amniotic epithelial stem cells-derived exosomes on healing of wound with full-thickness skin defect in rats. Methods: (1) Human amniotic epithelial stem cells were isolated from the amnion tissue of 5 full-term pregnant women in Department of Obstetrics of our hospital by the method of trypsin digestion, and their morphology was observed. The third passage of cells were stained with rhodamine-phalloidin for cytoskeleton observation. The third passage of cells were identified with flow cytometry through the detection of expressions of cell surface markers CD29, CD31, CD34, CD90, CD105, SSEA3, SSEA4 and immunity-related marker human leukocyte antigen-D related site (HLA-DR). The third passage of cells were also assessed the ability of adipogenic and osteogenic differentiation. (2) The third passage of human amniotic epithelial stem cells were cultured in DMEM medium supplemented with 10% exosome-free fetal bovine serum. Exosomes were isolated from culture supernatant by the method of ultracentrifugation and represented with scanning electron microscope for morphologic observation. (3) Six adult SD rats were anesthetized, and four 1 cm×1 cm sized wounds with full-thickness skin defect were made on the back of each rat. The wounds on the back of each rat were divided into control group, 25 μg/mL exosomes group, 50 μg/mL exosomes group, and 100 μg/mL exosomes group according to the random number table (with 6 wounds in each group), and a total volume of 100 μL phosphate buffered saline, 25 μg/mL exosomes, 50 μg/mL exosomes, and 100 μg/mL exosomes were evenly injected around the wound through multiple subcutaneous sites, respectively. The wound healing rate was calculated based on measurement on post injury day (PID) 7, 14, and 21. On PID 21, the healed wound tissue of each group was collected and stained with HE to observe and count skin accessories, and the arrangement of collagen fibers was observed with Masson staining. Data were processed with analysis of variance for repeated measurement, analysis of variance of randomized block design, one-way analysis of variance, and Bonferroni test. Results: (1) The cells, which were isolated and cultured, displayed typical cobblestone morphology with many microvilli on cell surface. Among the cells, the positive expression rates of CD29, CD90, SSEA3, and SSEA4 were above 50.0%, and the rate of CD105 was 8.0%, while the rates of CD31, CD34, and HLA-DR were almost 0. The cells could differentiate into adipocytes and osteoblasts. The above results revealed that the cells cultured were human amniotic epithelial stem cells. (2) Human amniotic epithelial stem cells-derived exosomes were round or oval vesicles with diameter from 50 to 150 nm. (3) On PID 7 and 21, wound healing rates of the four groups were close (with P values above 0.05). On PID 14, wound healing rates of 50 and 100 μg/mL exosomes groups were (89.8±4.3)% and (92.0±4.6)% respectively, significantly higher than the wound healing rate of control group [(80.3±6.4)%, P<0.05 or P<0.01]. Moreover, the wound healing rate of 100 μg/mL exosomes group was significantly higher than that of 25 μg/mL exosomes group [(83.3±5.1)%, P<0.05]. On PID 21, the numbers of skin accessories in 50 and 100 μg/mL exosomes groups were 4.3±1.4 and 5.1±1.6 respectively, obviously more than those of control group and 25 μg/mL exosomes group (respectively 1.4±0.5 and 1.8±0.6, with P values below 0.01). Well reorganized collagen fibers were observed just in the healed wound tissue of 50 and 100 μg/mL exosomes groups. Conclusions: Human amniotic epithelial stem cells-derived exosomes can promote healing of wound with full-thickness skin defect in rats.

[Effects of hypoxia on the phenotype transformation of human dermal fibroblasts to myofibroblasts and the mechanism]

Objective: To investigate the effects of hypoxia on the phenotype transformation of human dermal fibroblasts to myofibroblasts and the mechanism. Methods: The third passage of healthy adult human dermal fibroblasts in logarithmic phase were cultured in DMEM medium containing 10% fetal bovine serum for the following five experiments. (1) In experiments 1, 2, and 3, cells were divided into normoxia group and hypoxia group according to the random number table, with 10 dishes in each group. Cells of normoxia group were cultured in incubator containing 21% oxygen, while those of hypoxia group with 1% oxygen. At post culture hour (PCH) 0 and 48, 5 dishes of cells were collected from each group, respectively. mRNA expressions of markers of myofibroblasts including alpha smooth muscle actin (α-SMA), type Ⅰ collagen, and type Ⅲ collagen of cells were determined with real time fluorescent quantitative reverse transcription polymerase chain reaction in experiment 1. Protein expressions of α-SMA, type Ⅰ collagen, and type Ⅲ collagen of cells were determined with Western blotting in experiment 2. The protein expression of nuclear factor-kappa B (NF-κB) of cells was determined with Western blotting in experiment 3. (2) In experiment 4, cells were divided into normoxia group, hypoxia group, and hypoxia+ pyrrolidine dithiocarbamate (PDTC) group according to the random number table, with 5 dishes in each group. Cells in the former two groups were treated the same as those in experiment 1. Cells in hypoxia+ PDTC group were treated the same as those in hypoxia group plus adding 4 mL PDTC with a final molarity of 10 μmol/L in the culture medium. At PCH 48, the protein expression of NF-κB of cells was determined with Western blotting. (3) In experiment 5, cells were divided into normoxia group, hypoxia group, hypoxia+ PDTC group, and normoxia+ PDTC group according to the random number table, with 5 dishes in each group. Cells in the former three groups were treated the same as those in experiment 4. Cells in normoxia+ PDTC group were treated the same as those in normoxia group plus adding 4 mL PDTC with a final molarity of 10 μmol/L in the culture medium. At PCH 48, protein expressions of α-SMA, type Ⅰ collagen, and type Ⅲ collagen of cells were determined with Western blotting. Data were processed with analysis of variance of factorial design, one-way analysis of variance, and LSD-t test. Results: (1) Compared with those of normoxia group at corresponding time point, mRNA expressions and protein expressions of α-SMA, type Ⅰ collagen, and type Ⅲ collagen and the protein expression of NF-κB in fibroblasts of hypoxia group were not changed obviously at PCH 0 (with t values from -1.21 to 2.04, P values above 0.05), while mRNA expressions and protein expressions of α-SMA, type Ⅰ collagen, and type Ⅲ collagen and the protein expression of NF-κB significantly increased at PCH 48 (with t values from -12.57 to -3.44, P values below 0.01). (2) At PCH 48, the protein expression of NF-κB in fibroblasts of hypoxia group was 0.83±0.12, significantly higher than that of normoxia group (0.17±0.06, t=-16.96, P<0.001). The protein expression of NF-κB in fibroblasts of hypoxia+ PDTC group was 0.31±0.08, significantly lower than that of hypoxia group (t=12.73, P<0.001). (3) At PCH 48, protein expressions of α-SMA, type Ⅰ collagen, and type Ⅲ collagen in fibroblasts of hypoxia group were 0.73±0.09, 1.25±0.10, and 1.16±0.07, respectively, significantly higher than those of normoxia group (0.14±0.06, 0.87±0.08, and 0.77±0.13, respectively, with t values from 9.24 to 11.24, P values below 0.001). The protein expression of α-SMA in fibroblasts of normoxia+ PDTC group was 0.24±0.07, significantly higher than that of normoxia group (t=4.22, P<0.01). Protein expressions of type Ⅰ collagen and type Ⅲ collagen in fibroblasts of normoxia+ PDTC group were 0.25±0.06 and 0.32±0.11, respectively, significantly lower than those of normoxia group (with t values respectively -4.31 and -3.88, P values below 0.01). Protein expressions of α-SMA, type Ⅰ collagen, and type Ⅲ collagen in fibroblasts of hypoxia+ PDTC group were 0.09±0.08, 0.38±0.12, and 0.47±0.08, respectively, significantly lower than those of hypoxia group (with t values from 11.78 to 22.98, P values below 0.001). Conclusions: Hypoxia can significantly up-regulate the expressions of α-SMA, type Ⅰ collagen, and type Ⅲ collagen in human dermal fibroblasts, which may promote the phenotype transformation of fibroblasts to myofibroblasts, and this is likely to be associated with the activation of NF-κB signal pathway.

[To enhance study on translation and application of mesenchymal stem cells in wound repair]

Wound repair is a complicated process of interactions among numerous types of cells, involving the activation of multiple cells and various cytokines. The extensive burn and chronic wound are already big challenges for clinic due to the limitations of existing treatment means. Stem cell technology, as a new therapy, may be the optimum choice for wound repair. Mesenchymal stem cells are multipotent cells with self-renewal and differentiation capacity and have a broad tissue distribution, which are promising in treating wound, and it is worthy to discuss and analyze their role, clinical translation and application in wound repair, the facing problems at present and solving strategies as well.

[Advances in the research of nutrition therapy in patients with severe burn]

Patients with severe burn are characterized by strong oxidative stress and intense inflammatory response, which will cause metabolic disorder. Therefore, nutrition therapy is very important for severe burn. Nutrition therapy includes enteral nutrition (EN) and parenteral nutrition, and EN has the unique advantages. In recent years, more and more researchers focused on the EN for severe burn injuries, but there were still some confusing problems needing to solve. This article reviews the recent research about nutrition therapy for severe burn, including the route of feeding, energy requirements, and supplements of protein, carbohydrates, and microelements, and so on, so as to clarify some confusing questions about nutrition therapy for severe burn in clinical practice.

[Lay emphasis on the basic research in the field of burn surgery in China]

The therapeutic methods and effects have been improved greatly in burn care and management with several important advancements in the past few decades, resulting in more effective patient stabilization and significantly decreased mortality in China. However, the challenging clinical problems still exist, such as a lack of ideally efficient scheme and drugs to protect damaged tissue and internal organs after severe burn, the limited functional cosmetic outcomes of current treatment techniques and synthetic skin substitutes for deep burn wound repair and reconstruction, the high mortality of severe sepsis accompanying with burn injury patients, and the uncontrolled scar formation and modification or potential regeneration in burn wound healing, a further exploration into both underling mechanisms and curable therapies. This article emphasizes the important roles of the basic study in exploration of above clinical issues in the viewpoint of the advanced development of modern life sciences and relevant techniques.

[Cross merging promoting innovative development: a discussion on challenges and opportunities that burn surgery faces]

Burn surgery in the 21st century is now facing both serious challenges and opportunities for development. Interlacing of different disciplines is not only the source of scientific innovation and development in science of burn surgery, but also the trend of advancement of the discipline in the future. Therefore, it is imperative that burn surgery should strengthen multidisciplinary cooperation in order to develop new treatment concept and technology, widen and deepen basic researches with interdisciplinary methodology, and combine the translational medicine, integration medicine, and precision medicine, in order to form the salient feature of discipline of burn surgery.

Extracellular redox state regulates catecholamine biosynthesis in PC12 cells with insulin resistance

Extracellular cysteine (Cys)/cystine (CySS) redox potential (Eh) plays a crucial role in maintaining redox homeostasis and an alteration of redox state occurs in various physiological conditions, including diabetes, cancer, and aging. This study was designed to determine whether a variation in extracellular redox state would alter the function of insulin-resistant PC12 cells. Various redox states were established by providing different extracellular Cys/CySS Eh to insulin-resistant PC12 cells. We intensively investigated the relationship between redox state and catecholamine biosynthesis in PC12 cells, and evaluated the changes in cellular reactive oxygen species (ROS), catecholamine (CA) synthesis, tyrosine hydroxylase (TH) expressions, and the activity of rate-limiting enzyme in CA synthesis by using DCF-fluorescence, HPLC, and the real-time PCR, respectively. We also determined the protein levels of NF-E2-related factor 2 (Nrf2), a redox sensitive transcription factor, using an ELISA assay. We found that the oxidized Cys/CySS Eh (0 mV) pretreatment decreased CA, TH, and Nrf2 levels, but induced ROS overproduction. Insulin induced a significant increase in CA synthesis and ROS production, blocked by more reducing redox conditions. The paradox of CA and TH alterations between insulin and 0 mV groups may be attributed to degree of redox imbalance as evidenced by different ROS levels in 2 groups, which is further confirmed by CA alterations in different concentrations of hydrogen peroxide. Additionally, dithiole-3-thione (D3T, an inducer of Nrf2) corrected 0 mV-induced TH inhibition. In conclusion, CA biosynthesis in insulin-resistant PC12 cells could be influenced by extracellular Cys/CySS redox effects on cellular redox sensitive transcription factors.

A mechanism underlying hypertensive occurrence in the metabolic syndrome: cooperative effect of oxidative stress and calcium accumulation in vascular smooth muscle cells

Several lines of evidence indicate that reactive oxygen species (ROS) overproduction under the metabolic syndrome condition is the leading cause of cardiovascular events. Calcium is an important stimulus for vasoconstriction and plays a pivotal role in the development of hypertension. Here, we investigate whether a relationship exists between metabolic syndrome-induced mitochondrial ROS overproduction and Ang II-mediated Ca2+ release in vascular smooth muscle cells (VSMC). The effect of mitochondrial ROS on AT1 expression, and Ca2+ and IP3 generation was studied in 2 VSMC models of metabolic syndrome using fura-2/AM probes and ELISA-based assay. Ang II-mediated aortic ring contraction in SD rats fed with high-fat diet (HFD) was measured using a force transducer connected to chart recorder. In the metabolic syndrome, almost 2-fold increased mitochondrial O2 - significantly upregulated AT1 expressions by ~60%, companied by elevated Ca2+ and IP3 levels in VSMC and enhanced aortic rings contraction. All these increments were blocked by rotenone (inhibitor of mitochondrial respiratory chain complex I), ruthenium red (inhibitor of calcium uniporter), cyclosporin A (inhibitor of mitochondrial permeability pore), and N-acetylcysteine. Therefore, in the states of metabolic syndrome, ROS overproduction in mitochondrial complex I enhances Ang II-mediated vascular contraction via an AT1-dependent pathway. In addition, the import of Ca2+ from endoplasmic reticulum to mitochondria via calcium uniporter and mitochondrial permeability pore seems to serve as a mechanism to further aggravate mitochondrial damage and vascular dysfunction that may contribute to the occurrence of hypertension.

[The biological effect of matrix metalloproteinase-1 in epidermal repair]

OBJECTIVE

To review the role of matrix metalloproteinase-1 (MMP-1) in the course of healing in wounded skin.

METHODS

The recent literatures on MMP-1 in skin wound repair were reviewed, which gave the insight into the local effect of MMP-1 during re-epithelialization.

RESULTS

Following injury, basal keratinocytes, moving from the wound edge and interact with dermal matrix proteins in the wound bed, were induced to express MMP-1 in a specific space-time pattern. MMP-1 cleaved the collagen, thereby altering its structure and affinity by which the keratinocytes binded it. MMP-1 served a beneficial role in wound healing by facilitating the proliferation and movement of keratinocytes over the collagen-rich wound bed during re-epithelialization.

CONCLUSION

MMP-1 expression of migrating keratinocytes directly influences the re-epithelialization during the course of healing of the wounded skin.

[Effect of microsectioning medulla, pH and temperature on rhythmical respiratory discharge activity of medulla-spinal preparation isolated from newborn rat]

AIM AND METHODS

The brain stem and the spinal cord were isolated from 0-4-day-old rats, placed in a bath and perfused with artificial cerebrospinal fluid (aCSF) in vitro. Spontaneous rhythmic neural activity could be recorded from phrenic (C4v, C5v) and hypoglossal nerves (XII). By microsection of medulla of medulla-spinal preparation, rhythmical respiratory discharge activity (RRDA) of C4v, C5v and XII were observed.

RESULTS

Medulla-spinal preparation survival about six to eight hours when preparation was perfused continuously with aCSF. RRDA of C4v or C5v and XII was synchronous and continued about four to six hours. RRDA of C4v or C5v and XII could not be perturbed until a level of 500 microm rostral to obex was reached when cutting brain stem coronally in a rostral-to-caudal direction, and until a horizontal plane at middle level was reached when cutting brain stem dorsal-ventrally from dorsal surface of the stem. RRDA of XII also could not be perturbed until a level just caudal to the caudalis root of the XII (50 micro m caudal to the obex) when cutting brain stem caudal-rostrally. Frequency of respiration gradually decreased and amplitude of RRDA gradully enhanced when pH of fluid perfused from 7.45 up to 7.85, and RRDA enhanced when from 7.35 down to 6.85 and ceased when 4.5 RRDA enhanced when temperature of fluid perfused from 27 degrees C up to 37 degrees C, and decreased when from 38 degrees C up to 41 degrees C and when from 27 degrees C down to 23 degrees C, and ceased when 42 degrees C or 22 degrees C.

CONCLUSION

A respiratory rhythm generating site is located in mNRF, there are neurons those are susceptible to change of pH and temperature in mNRF.