TGF-β 3c2s2基因转染骨髓间充质干细胞对创面愈合中转化生长因子β表达的影响及意义

目的：外伤后病理性瘢痕的形成与创面的愈合过程有着密切的联系。创伤愈合时期引入细胞因子或生长因子及其他影响因素。调节创伤愈合机制，即可能改变细胞外基质结构。达到预防瘢痕形成的目的。实验拟观察TGF-β3c2s2基因转染的骨髓间充质干细胞在创面修复与重塑过程中对转化生长因子β1和转化生长因子β3表达的影响。 方法：实验于2005-10／2007-03年在重庆医科大学附属儿童医院外科实验室、动物实验中心完成。①实验材料：四五周龄日本大耳白兔2只，体质量300～400g，雌雄不限；健康成年日本大耳白兔20只。体质量1．7-2．5kg。雌雄不限，均由重庆医科大学动物实验中心提供，实验过程中对动物处置符合动物伦理学标准。②实验方法：选取四五周龄日本大耳白兔分离培养骨髓闻充质干细胞。选取健康成年日本大耳白兔20只，每只兔耳腹侧制作2个皮肤、软骨全层缺损创面共80个。创面以自身对照为前提随机分为4组。每组20个创面：实验组：加入Ad—TGF-β3c2s2转染的骨髓间充质干细胞：空白对照组：加入消毒的DMEM／F12（不含胎牛血清）：腺病毒组：加入Ad—TGF—β3c2s2腺病毒；骨髓间充质干细胞组：加入骨髓间充质干细胞。③实验评估：观察瘢痕形成情况。苏木精-伊红染色、免疫组织化学技术观察瘢痕组织的组织学形态和检测瘢痕组织中转化生长因子β1和转化生长因子β3表达和变化规律。 结果：①实验组在整个过程中无明显高出周围皮肤的瘢痕形成。其他组上皮化后。创面均逐渐形成不同程度的瘢痕。伤后45d瘢痕增生程度达高峰。明显高出皮肤表面；持续至90d左右。②实验组和腺病毒组结构较接近正常皮肤，比正常皮肤胶原排列致密。略厚：空白对照组、骨髓间充质干细胞组伤后45d可见浅层组织结构排列紊乱。胶原纤维粗大?     

磷脂多不饱和脂肪酸抑制兔耳增生性瘢痕

背景：多不饱和脂肪酸有抑制细胞炎症反应及免疫功能的作用,增生性瘢痕的形成与炎症、细胞免疫、细胞因子有着密切关系,但目前尚无应用多不饱和脂肪酸防治增生性瘢痕的实验研究。目的：探讨磷脂多不饱和脂肪酸对兔耳增生性瘢痕的抑制作用。方法：在9只新西兰大白兔兔耳腹侧做直径1cm的圆形全层皮肤缺损创面,每侧6个,共108个,其中形成增生性瘢痕92个,瘢痕形成率为85%。实验分3组：每只兔耳靠前3个创面涂磷脂多不饱和脂肪酸霜,右耳靠后3个创面涂多磺酸黏多糖乳膏,创面上皮化后立即涂药,每日1次,左耳靠后3个创面自然愈合。分别在术后28,42,63,90d,观察创面的愈合情况;显微镜下观察瘢痕组织的厚度、胶原纤维和成纤维细胞密度;免疫组织化学染色检测胶原纤维的表达。结果与结论：涂抹磷脂多不饱和脂肪酸霜和多磺酸黏多糖乳膏可使增生性瘢痕体积缩小、厚度变薄、成纤维细胞密度减小、胶原纤维表达减少。尤以磷脂多不饱和脂肪酸霜的效果最为明显。说明磷脂多不饱和脂肪酸可抑制兔耳增生性瘢痕的形成,减轻瘢痕的增生程度。     

转化生长因子βⅠ型受体、Ⅰ型胶原在人皮肤增生性瘢痕组织周边区和中心区的表达

背景:近年来国内外学者对转化生长因子β及其受体的研究较多,但转化生长因子β受体1在增生性瘢痕组织周边区分布情况尚未见报道.目的:比较转化生长因子βⅠ型受体和Ⅰ型胶原在人皮肤增生性瘢痕组织周边区和中心区表达与分布.方法:收集新疆医科大学第一附属医院整形外科和新疆医科大学附属肿瘤医院乳腺、头颈外科1999/2002住院及门诊各类瘢痕手术患者30例,其中增生性瘢痕20例;非增生性瘢痕10例.取材瘢痕中心区、周边区及正常皮肤组织,每例6块共180块.用免疫组织化学方法检测组织转化生长因子βⅠ型受体、Ⅰ型胶原蛋白含量,对其阳性反应进行定量统计分析.结果与结论;增生性瘢痕组织转化生长因子βⅠ型受体、Ⅰ型胶原水平明显高于非增生性瘢痕组织和正常皮肤,且免疫阳性反应强.增生性瘢痕周边区转化生长因子β、型受体含量100%,明显高于中心区20%(P<0.05);而Ⅰ型胶原中心区与周边区均为100%,差异无显著性意义.非增生性瘢痕周边区、中心区转化生长因子βⅠ型受体、Ⅰ型胶原差异无显著性意义(P>0.05):正常皮肤组织转化生长因子βⅠ型受体、Ⅰ型胶原含量极少.结果提示,增生性瘢痕周边区转化生长因子βⅠ型受体表达高于中心区,增生性瘢痕周边区的防治可能是临床防治工作的重点.     

Platelet‐derived transforming growth factor‐β1 promotes keratinocyte proliferation in cutaneous wound healing

Platelets are a recognised potent source of transforming growth factor‐β1 (TGFβ1), a cytokine known to promote wound healing and regeneration by stimulating dermal fibroblast proliferation and extracellular matrix deposition. Platelet lysate has been advocated as a novel personalised therapeutic to treat persistent wounds, although the precise platelet‐derived growth factors responsible for these beneficial effects have not been fully elucidated. The aim of this study was to investigate the specific role of platelet‐derived TGFβ1 in cutaneous wound healing. Using a transgenic mouse with a targeted deletion of TGFβ1 in megakaryocytes and platelets (TGFβ1^fl/fl.PF4‐Cre), we show for the first time that platelet‐derived TGFβ1 contributes to epidermal and dermal thickening and cellular turnover after excisional skin wounding. In vitro studies demonstrate that human dermal fibroblasts stimulated with platelet lysate containing high levels of platelet‐derived TGFβ1 did not exhibit enhanced collagen deposition or proliferation, suggesting that platelet‐derived TGFβ1 is not a key promoter of these wound healing processes. Interestingly, human keratinocytes displayed enhanced TGFβ1‐driven proliferation in response to platelet lysate, reminiscent of our in vivo findings. In summary, our novel findings define and emphasise an important role of platelet‐derived TGFβ1 in epidermal remodelling and regeneration processes during cutaneous wound healing.     

兔耳增生性瘢痕的形态学观察与羟脯氨酸含量变化

Inrecentyears，excessivedermalhyperplasiafollowingtotalskinlossofrabbit＇seariswidelyreportedbydomesticandforeignre－searchers．Histologicalstudiesshowexcessivedermalhyperplasiahascloserelationwithhypertrophicscarofhuman犤１－２犦．Characteristicsofcollagenmetabolismandmorphologicalchangeslawaboutexcessivedermalhyperplasiaremainunclear．Theinvolvedmechanismistheobjectiveofthisstudy．１Materialandmethod１．１Treatmentandcreationofwoundsinanimals８Japaneselarge－earrabbitsregardingnogenderwerei…     

密闭性敷料在小儿慢性伤口的应用研究

目的探讨处理小儿慢性伤口的最佳治疗方法以及创面愈合中保持湿润的最佳时间。方法选择同类伤口观察组和对照组各50例,对照组采用传统的纱布敷料覆盖,观察组则根据伤口的不同愈合阶段选择适当的密闭透气性敷料覆盖,分别在使用后2 d3、d、4 d5、d观察创面肉芽组织生长情况及不同通透性的透气膜对伤口愈合的影响。采用同一标准观察两组伤口愈合时间、换药时间及次数。结果观察组伤口愈合时间明显缩短,换药时疼痛明显减轻,换药次数及时间减少,平均治疗费用降低25%左右。结论根据伤口的状况及不同愈合阶段采用适当的密闭性敷料,可明显缩短伤口愈合时间,减少瘢痕的形成。同时观察到,在小儿慢性伤口红色期以间隔3~4 d换药时间最佳,透气膜的通透性越小,上皮的再生越快。     

Extracorporeal shock wave treatment improves incisional wound healing in diabetic rats

Impaired wound healing in surgical patients with diabetes increases the incidence of infection, prolongs hospitalization, and even increases the rate of mortality. Low-energy extracorporeal shock wave treatment (ESWT) was reported to accelerate chronic wound healing by promoting revascularization and tissue regeneration; however, it is not known if ESWT could also improve healing of acute surgical incisional wounds in diabetes. In this study, using a rat model of diabetes, we investigated the effect of low-energy ESWT on collagen content in wound tissues and its efficacy in incisional wound healing. A single dorsal incisional wound was inflicted in streptozotocin-induced diabetic rats, and they received ESWT at different time post-wounding. Rats were sacrificed on days 7 and 14 post-wounding. Wound breaking strength, hydroxyproline content, histological characteristics and the expression of transforming growth factor beta 1 (TGF-β1) were analyzed. As a result, the wound breaking strength was significantly enhanced and the hydroxyproline content in wound tissues was increased at each time point examined. The number of fibroblasts was signicantly increased, and the new collagen fibers were more abundant at the wound site after ESWT. Furthermore, the expression of TGF-β1 was up-regulated after ESWT on day 7 post-wounding. These results suggest that low-energy ESWT can increase collagen content, enhance wound breaking strength and improve the healing of incisional wound in diabetic rats. The increased collagen content may be attributed, at least in part, to the up-regulation of TGF-β1 expression in wound tissues.     

Analysis of hypertrophic and normal scar gene expression with cDNA microarrays

Hypertrophic scar is one form of abnormal wound healing. Previous studies have suggested that hypertrophic scar formation results from altered gene expression of extracellular matrix molecules. A broadscale evaluation of gene expression in hypertrophic scars has not been reported. To better understand abnormalities in hypertrophic scar gene expression, we compared messenger RNA expression in hypertrophic scars, normal scars, and uninjured skin with the use of complementary (c)DNA microarrays. Total RNA was extracted from freshly excised human hypertrophic scars, normal scars, or uninjured skin and reverse transcribed into cDNA with the incorporation of [33P] deoxycytidine triphosphate. The resulting radioactive cDNA probes were hybridized onto cDNA microarrays of 4000 genes. Hybridization signals were normalized and analyzed. In the comparison of tissue samples, mean intensities were calculated for each gene within each group (hypertrophic scars, normal scars, and uninjured skin). Ratios of the mean intensities of hypertrophic scars to normal scars, hypertrophic scars to uninjured skin, and normal scars to uninjured skin were generated. A ratio that was greater than 1 indicated upregulation of any particular gene and a ratio that was less than 1 indicated downregulation of any particular gene. Our data indicated that 142 genes were overexpressed and 50 genes were underexpressed in normal scars compared with uninjured skin, 107 genes were overexpressed and 71 were underexpressed in hypertrophic scars compared with uninjured skin, and 44 genes were overexpressed and 124 were underexpressed in hypertrophic scars compared with normal scars. Our analysis of collagen, growth factor, and metalloproteinase gene expression confirmed that our molecular data were consistent with published biochemical and clinical observations of normal scars and hypertrophic scars. cDNA microarray analysis provides a powerful tool for the investigation of differential gene expression in hypertrophic scar samples and either uninjured skin or normal scars. Our data validate the use of this technology for future studies on gene expression during repair processes of normal and abnormal wounds.     

Recombinant human erythropoietin stimulates angiogenesis and healing of ischemic skin wounds

Wound healing in ischemic tissues such as flap margins due to inadequate blood supply is still a source of considerable morbidity in surgical practice. Adequate tissue perfusion is particularly important in wound healing. We investigated the effects of recombinant human erythropoietin (rHuEPO) on wound healing in an ischemic skin wound model. Sixty-three Sprague-Dawley rats were used. Normal incisional wound and H-shaped double flaps were used as the wound models. Animals were treated with rHuEPO (400 IU/kg) or its vehicle. Rats were killed on different days (3, 5, and 10 days after skin injury) and the wounded skin tissues were used for immunohistochemistry and for analysis of vascular endothelial growth factor content and collagen content. Tissue transglutaminase immunostaining of histological specimens was used as a vascular marker to determine the level of microvessel density. The results showed a higher level of vascular endothelial growth factor protein and an increased microvessel density in ischemic wounds with rHuEPO treatment than the normal incisional wounds and ischemic control wounds. Collagen content was higher in the incisional wounds and in the ischemic wounds with rHuEPO treatment compared with the ischemic control wounds. Our results suggest that erythropoietin may be an effective therapeutic approach in improving healing in ischemic skin wounds.     

碱性成纤维细胞生长因子对增生性瘢痕与正常皮肤成纤维细胞胶原、纤维连接蛋白表达的影响

背景:碱性成纤维细胞生长因子能促进愈合伤口产生胶原蛋白、纤维连接蛋白和基质酶的基质成分.然而,细胞增殖、细胞外基质及新生血管的形成或伤口基质重塑过程失调,会导致瘢痕组织过度增殖.目的:观察碱性成纤维细胞生长因子在正常皮肤创面愈合和增生性瘢痕形成中的作用.方法:从5例进行瘢痕修复手术患者身上同时取正常皮肤和增生性瘢痕组织,分离培养正常人皮肤成纤维细胞和增生性瘢痕成纤维细胞.应用RT-PCR和酶联免疫吸附法检测两种成纤维细胞胶原、纤维连接蛋白基因表达和蛋白合成.采用JC-1染色和流式细胞术测定成纤维细胞线粒体膜电位改变,采用化学发光法检测细胞内ATP水平改变.观察碱性成纤维细胞生长因子对两种细胞的上述指标的影响.结果与结论:不同浓度碱性成纤维细胞生长因子可减慢增生性瘢痕成纤维细胞生长,抑制增生性瘢痕成纤维细胞Ⅰ型胶原表达和合成(P<0.05).碱性成纤维细胞生长因子对正常皮肤和增生性瘢痕成纤维细胞Ⅲ型胶原表达和合成均无影响.然而可上调正常皮肤成纤维细胞表达纤维连接蛋白(P<0.05).此外,10,100 μg/L碱性成纤维细胞生长因子处理后增生性瘢痕成纤维细胞线粒体膜电位呈去极化趋势,正常皮肤成纤维细胞中ATP水平显著增高(P<0.05).结果表明,碱性成纤维细胞生长因子在正常皮肤创面愈合和增生性瘢痕形成中可能有不同的作用和机制.     

Promotion of diabetic wound healing by collagen scaffold with collagen‐binding vascular endothelial growth factor in a diabetic rat model

Aims: Studies show that VEGF can promote tissue regeneration in diabetic wounds. The aim of this study was to evaluate the effects of a new composite biomaterial, a collagen scaffold with CBD‐VEGF, for wound healing in a diabetic rat model. Materials and methods: We produced a collagen scaffold loaded with CBD‐VEGF, which allowed VEGF to bind to the collagen scaffold. The diabetic rat model was constructed by injecting streptozocin (STZ) peritoneally and removing a 2 x 2.5 cm thick slice of skin from the back of the animal. Animals were randomly divided into 4 groups: blank control (BC Group, n = 24), collagen scaffold loaded with PBS (PBS Group, n = 24), collagen scaffold loaded with NAT‐VEGF (NAT‐VEGF Group, n = 24), and collagen scaffold loaded with CBD‐VEGF (CBD‐VEGF Group, n = 24). Wounds of the BC Group were covered with gauze and those of the PBS, NAT‐VEGF and CBD‐VEGF Groups were grafted by corresponding collagen scaffolds, respectively. Healing rates were calculated and compared among groups. Wound tissue was evaluated by histologic analysis. Results: The CBD‐VEGF group showed a higher wound healing rate, better vascularization and higher level of VEGF in the granulation tissue wound compared with NAT‐VEGF and PBS groups. Conclusions: The collagen scaffold with CBD‐VEGF promoted wound healing in a diabetic rat model, which could potentially provide better therapeutic options for the treatment of diabetic wounds. Copyright © 2012 John Wiley & Sons, Ltd.     

细菌纤维素减轻兔耳增生性瘢痕的作用

背景：国内外已有研究报道细菌纤维素对皮肤创伤愈合具有促进作用,但是其对增生性瘢痕是否有治疗作用尚不清楚。目的：观察细菌纤维素对兔耳增生性瘢痕的疗效。方法：建立兔耳腹侧增生性瘢痕模型,术后第21天创面上皮化后,对每只兔耳5个不同瘢痕面随机给予5种不同处理方式：持水性分别为1：5,1：6,1：8细菌纤维素组、阳性对照组（贴敷瘢痕贴）、阴性对照组（未贴任何敷料且瘢痕自然生长）。观察不同处理后第0,14,21,28,42,56天瘢痕面大体形态学及组织学变化。结果与结论：持水性1：5,1：6,1：8细菌纤维素组瘢痕增生厚度低于阴性对照组,但高于阳性对照组（P〈0.01）。与阴性对照组比较,持水性1：5,1：6,1：8细菌纤维素组瘢痕组织中真皮层薄,成纤维细胞少,胶原纤维较细、排列较整齐;与阳性对照组组比较,持水性1：5,1：6,1：8细菌纤维素组成纤维细胞数稍多,胶原也稍粗、排列也稍不整齐。3种细菌纤维素组间瘢痕厚度及成纤维细胞数量为1：5细菌纤维素组〉1：6细菌纤维素组〉1：8细菌纤维素组（P〈0.05）。说明细菌纤维素有效抑制了兔耳创面愈合后增生性瘢痕的形成,并且持水性越高,效果越好。     

Wound Healing Activities of Rafflesia Hasseltii Extract in Rats

The effects of topical application of Rafflesia hasseltii buds and flowers extract on the rate of wound healing and histology of healed wound were assessed. Four groups of adult male Sprague Dawley rats were experimentally wounded in the posterior neck area. A thin layer of blank placebo was applied topically to wounds of Group 1 rats. Wounds of experimental animals (Group 2 and 3) were treated with placebo containing 5% and 10% R. hasseltii buds extract, respectively. A thin layer of Intrasite gel was applied topically to wounds of Group 4 animals as reference. Macroscopically, wounds treated with placebo containing 5% and 10% R. hasseltii buds extract or Intrasite gel have been significantly accelerated the rate of wound healing compared to placebo-treated wounds. Histological analysis of healed wounds has confirmed this effect. Wounds treated with placebo containing 5%, 10% R. hasseltii buds extract or Intrasite gel showed markedly less scar width at wound enclosure and granulating tissue contained markedly more collagen and proliferating fibroblasts, but with the absence of inflammatory cells compared to wounds treated with blank placebo. In conclusion, the findings of increased rate of wound closure and contraction together with the histological findingssuggest that Rafflesia hasseltii buds extract is very effective in accelerating the wound healing process.     

Development of a Histomorphologic Scale to Quantify Cutaneous Scars after Burns

OBJECTIVE: Cutaneous wound healing in adults invariably results in scarring; however, there are few scales to quantify the degree of such scarring. The authors developed a histomorphologic scale for quantifying scarring after cutaneous burn injury. METHODS: As part of a randomized trial comparing a variety of burn therapies, 40 partial-thickness burns were created on the backs and flanks of anesthetized pigs and treated with a tissue adhesive, antibiotic ointment, occlusive dressing, or dry gauze. Gross scar appearance was independently assessed by two investigators at 90 days on a 100-mm visual analog scale (VAS) marked "best appearance" at the high end. One of the investigators repeated the observation 30 days later. Full-thickness biopsies were taken 90 days after injury and evaluated histologically by a dermatopathologist for the presence of hyperkeratosis, epidermal hyperplasia, presence and depth of scar (defined as abnormally oriented collagen under polarized light), fibroplasia, vascular proliferation, and absence of adnexa, including hair follicles, apocrine glands, and smooth muscles. One point was assigned for each category in the presence of a normal finding, whereas an abnormal finding was assigned a score of zero. The normal dermis (absence of abnormal collagen) was given a score of 3, while decreasing scores of 2 to 0 were given for progressively deeper scars (i.e., 2 for papillary dermis, 1 for upper half of reticular dermis, and 0 for deep dermal lower half). The total histomorphologic score was derived by adding the scores on the individual items. The score ranges from 0 to 10 from worst scarring to absence of scarring, respectively. A subset of observations was evaluated a second time by one of the observers one month later. Intraobserver reliability of the histomorphologic scale was assessed with Spearman's correlation. Inter- and intraobserver Pearson's correlations for the gross scar VAS were calculated, and the correlation between gross and histomorphologic scores was assessed. RESULTS: Intraobserver correlation for individual histomorphologic categories ranged from 0.19 to 1.00. Intraobserver correlation for the total histologic score was 0.95. Inter- and intraobserver correlations for the gross scar VAS were 0.8 each. Correlation between the histomorphologic scale and the gross scar VAS was 0.38. CONCLUSIONS: A new reliable histomorphologic method for quantifying and scoring cutaneous scars is described together with a reliable scar VAS. However, these two scales are not highly correlated.     

The effect of lidocaine/prilocaine cream on an experimental wound healing model.

The effects of lidocaine/prilocaine cream on wound healing were evaluated in this study. An incisional wound model on abdominal wall was performed on mice. A full thickness skin incision 2 cm in length was performed then it was sutured primarily with 4/0 polypropylene. In group I (n = 10) only suturing was done (control group), in group II (n = 10) lidocaine cream was applied after suturing on wound site and it was repeated for 6 days (twice in a day), in group III (n = 10) lidocaine/prilocaine cream was applied topically after suturing and repeated 6 days (twice in a day). At day 7, incisions were excised for evaluating tensile strength and 5-hydroxyproline (5-HP) values. Tensile strength values were lowest in control group and highest in lidocaine/prilocaine treatment group. 5-HP values were also expressed the same results. Both tensile strength and 5-HP values increased significantly in treatment groups in regard to the control (p < 0.05). It was concluded that lidocaine/prilocaine cream as topical anaesthetic agent had no adverse effect in an incisional wound model, furthermore it may have some beneficial effects on wound healing which remains to be evaluated and it can be used safely in day-to-day emergency practices.     

Effects of topical elk velvet antler on cutaneous wound healing in streptozotocin-induced diabetic rats

OBJECTIVE: Wound repair is a finely orchestrated process involving cellular, molecular, physiologic, and biochemical interactions that restore the integrity of damaged tissue. Cyclic replacement of deer antlers requires rapid regenerative growth, in many ways analogous to that encountered during tissue repair. Molecular mechanisms regulating these processes are not fully understood, but it is increasingly apparent that growth factors are important mediators. Previous studies have shown that elk velvet antler (EVA) contains various growth factors and that a water-soluble extract stimulates dermal fibroblast growth in vitro. DESIGN: The efficacy of EVA water-soluble extract on wound healing in streptozotocin-induced diabetic rats was EVAluated using a full-thickness cutaneous wound model. Animals were randomly selected to receive topical application of either control or EVA gel. Daily photographs of the wounds served to measure the rate of wound closure. Wound-edge biopsies obtained on postoperative days 2 and 10 allowed histologic evaluation and measurement of transforming growth factor-beta 1 (TGF-beta (1)) concentrations by enzyme-linked immunoabsorbent assay. RESULTS: Wounds treated with the EVA topical gel were significantly smaller by postoperative day 6. TGF- beta (1) protein expression was not different in EVA-treated wounds compared to control wounds. CONCLUSIONS: This study indicates that topical treatment with an EVA water-soluble extract accelerates repair of cutaneous wounds in diabetic rats. Further studies are warranted to reveal the mechanisms involved in EVA enhancement of wound closure and to determine if this compound is an economical pharmacologic agent in the treatment of normal and compromised wounds.     

The Presence of B-type Natriuretic Peptide in Burns and the Responsiveness of Fibroblasts to BNP: Proof of Principle

Background: B‐type natriuretic peptide (BNP) released from cardiac myocytes plays an important role in cardiac homeostasis through cyclic guanosine monophosphate (cGMP) activation. BNP also reduces cardiac remodeling and fibrosis. The antifibrotic effects of BNP are mediated in part by blocking the effects of transforming growth factor β, a profibrotic cytokine that plays a significant role in cutaneous wound healing. It is unclear if BNP plays any role in cutaneous wound healing. Objectives To investigate if BNP levels would be elevated in thermally injured human skin and if human‐derived fibroblasts would respond to BNP exposure by increasing levels of cGMP. Methods This was an in vitro analysis of human skin. Skin samples and cells were collected from patients with and without thermal injury. The authors stained three skin samples from normal skin (taken at the time of elective cosmetic surgery) with antibodies to BNP and compared these with three tissue samples obtained from burned human skin taken during tangential excision of deep burns. Normal human‐derived fibroblasts and keratinocytes were exposed in triplicate to BNP in vitro, and cGMP accumulation was evaluated. Levels of cGMP were quantified and compared with analysis of variance. Results BNP was present in all specimens of thermally injured skin (especially around collagen, epithelial cells, and endothelial cells) but not in any uninjured skin samples (p = 0.05, single‐tailed Fisher's exact test). In vitro grown fibroblasts showed significant increases of cGMP levels with increasing levels of BNP exposure (mean [±SD]: 0.6 [±0.3], 1.2 [±0.2], 4.6 [±0.1], and 5.0 [±0.9] pmol/mL with BNP concentrations of 0, 10, 500, and 1,000 nmol/L, respectively; p < 0.001). The effect of BNP on keratinocytes was minimal and below the level of quantification. Conclusions: These findings demonstrate proof of principle that human fibroblasts are responsive to the effects of BNP in vitro and that BNP is present in injured skin, suggesting that BNP may play a role in cutaneous wound healing.     

Reduced wound contraction after grafting of full-thickness burns with a collagen and chondroitin-6-sulfate (GAG) dermal skin substitute and coverage with biobrane

Full-thickness burns destroy both the epidermal and dermal tissues of the skin. This study evaluates a collagen and chondroitin-6-sulfate dermal skin substitute (graft) that was applied to excised full-thickness burns and covered with Biobrane. Experimental conditions included: (a) no burn, subcutaneous implantation of the graft; (b) burn, excision, graft, coverage with Biobrane and bandages; (c) burn, excision, no graft, coverage with Biobrane and bandages; (d) burn only. forty-one days post-surgery, subcutaneous implantation (N = 3) of the graft caused no detectable contraction or necrosis of the overlying skin, whereas all burn wounds contracted. Measurements of wounds (percentage of original wound size) showed statistically significant differences between the following treatments; (a) graft plus Biobrane (N = 10), 34%; (b) no graft plus Biobrane (N = 9), 25%; (c) untreated burns (N = 6), 16%. Semi-quantitative evaluation of time to healing indicated by spontaneous detachment of Biobrane from wounds showed that grafted, excised wounds healed in an average of 2.7 weeks, while ungrafted, excised wounds required an average of 4.3 weeks to heal. Histological appearance of healed wounds after grafting and coverage with Biobrane resembles undamaged skin without epidermal adnexal structures. Excision of full-thickness burn eschar, followed by grafting with a collagen and chondroitin-6-sulfate dermal skin substitute and coverage with Biobrane provides reduced wound contraction within a six-week period of observation compared to non-excised wounds. Both more rapid and more complete wound healing took place compared to excised wounds that were not grafted.     

Functionalized PVA–silk blended nanofibrous mats promote diabetic wound healing via regulation of extracellular matrix and tissue remodelling

Chronic cutaneous ulcers, a complex pathophysiological diabetic condition, represent a critical clinical challenge in the current diabetes mellitus pandemic. Consequently, there is a compelling need for bioactive dressings that can trigger healing processes for complete wound repair. Silk fibroin (SF), a natural protein polymer from mulberry and non‐mulberry silkworms, has properties that support accelerated wound healing rate. SF from non‐mulberry variety possesses additional cell‐binding motifs (arginine, glycine, and aspartate), offering cell–material interactions. This study is aimed to investigate wound healing efficacy of dressings made up of various SF varieties blended with poly(vinyl alcohol) biopolymer in alloxan‐induced diabetic rabbit model. The nanofibrous mats have been developed using electrospinning and functionalized with growth factors and LL‐37 antimicrobial peptide for sustained delivery. Following post 14‐day treatment, non‐mulberry SF (NMSF)‐based dressings healed the wounds faster, in comparison with their mulberry Bombyx mori SF, poly(vinyl alcohol), and control counterparts (p < .01). NMSF‐based dressings also supported faster granulation tissue development, angiogenesis, and reepithelialization of wounds. Gene expression study of matrix metalloproteinases and collagen proteins affirmed higher extent of tissue remodelling during the repair process. Furthermore, there was organized extracellular matrix deposition (collagen type I, collagen type III, elastin, and reticulin) and higher wound breaking strength in NMSF compared with other groups after 4 weeks. These results validated the potential of NMSF‐based bioactive dressings to regulate extracellular matrix deposition leading to faster and complete repair of chronic diabetic cutaneous wounds.     

烫伤创面愈合后的瘢痕形成与神经支配

背景:既往研究表明神经因素在创面愈合中具有重要调控作用,但有关神经调节与创面愈合后瘢痕形成之间的关系鲜有报道。目的:观察烧伤创面愈合过程中神经支配与创面愈合质量之间的关系。方法:将30只大鼠右侧T9~L1阶段脊神经根切断,制作失神经支配皮肤模型;然后在大鼠背部右侧失神经支配皮肤区域制作直径4cm的深Ⅱ度烫伤创面,设为模型组,左侧对称正常皮肤制作同样的创面,设为对照组,伤后连续观察创面变化,于7,14,21 d采用免疫组织化学法观察Ⅰ和Ⅲ胶原分泌情况,并计算Ⅰ/Ⅲ型胶原比例的变化,探讨创面愈合速度及愈合质量。结果与结论:模型组Ⅰ,Ⅲ型胶原分泌和Ⅰ/Ⅲ型胶原比值于伤后各时间点均显著低于对照组(P<0.05)。模型组Ⅰ型胶原分泌与伤后7,14,21 d逐渐增加(P<0.05),Ⅲ型胶原于伤后21 d时分泌明显增高(P<0.05),Ⅰ/Ⅲ型胶原比值与伤后21 d时明显降低(P<0.05)。结果证实,创面早期神经支配可以促进创面愈合,创面重塑期减轻神经支配可能会改善创面重塑质量。