The antifibrogenic effects of liposome-encapsulated IFN-alpha2b cream on skin wounds.

Interferons (IFN), including IFN-alpha2b, have been used as antifibrogenic factors to modulate the excessive production of extracellular matrix (ECM) associated with dermal fibroproliferative disorders. This study was conducted to examine the ability of a dermal cream containing liposome-encapsulated IFN-alpha2b (LIPO+IFN) to affect the synthesis of ECM in open and reepithelialized wounds. Full-thickness skin wounds in 32 female Hartley guinea pigs (6 wounds per animal, 3 on each side) were made with an 8-mm biopsy punch. Each wound on the right side received 3,000 U LIPO+IFN, whereas wounds on the left side received cream containing empty liposomes. Histologic examination revealed a significant reduction in scar formation in LIPO+IFN-treated but not in vehicle-treated wounds. Northern analysis showed reductions in type I procollagen mRNA in healed wounds treated with LIPO+IFN (day 4 groups: 1596.9 +/- 207 vs. 3710.2 +/- 493 densitometry units, p < 0.01, n = 8). This was consistent with a reduction in the concentration of collagen in the tissue, assayed as 4-hydroxyproline (day 4 group: 38.5 +/- 3.8 vs. 54.5 +/- 3.9 microg per tissue, p < 0.01, n = 8). Even when applied to reepithelialized wounds, LIPO+IFN caused a marked reduction in type I collagen mRNA (1938.5 +/- 579 vs. 4085.7 +/- 1271 densitometry units, p < 0.01, n = 8). These findings support the concept of the early topical use of this antifibrogenic agent for treatment of dermal fibroproliferative disorders, such as hypertrophic scars.     

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1 cm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28,42,63,90 d,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。     

Ski, a modulator of wound healing and scar formation in the rat skin and rabbit ear

We recently demonstrated that Ski is a novel wound healing-related factor that promotes fibroblast proliferation and inhibits collagen secretion. Here, we show that increasing local Ski expression by gene transfer not only significantly accelerated wound healing by relieving inflammation, accelerating re-epithelialization and increasing formation of granulation tissue, but also reduced scar formation by decreasing collagen production in rat dermal wounds. Similarly, ski gene transfer accelerated wound healing, reduced the protuberant height and volume of scars and increased collagen maturity in a hypertrophic scar model in the rabbit ear. Conversely, reducing Ski expression in the wound by RNA interference resulted in significantly slower wound healing and increased scar area in rat dermal wounds. We demonstrated that these effects of Ski are associated with transforming growth factor-β-mediated signalling pathways through both Smad2/3-dependent and Smad-independent pathways. Together, our results define a dual role for Ski in promoting wound healing and alleviating scar formation, identifying a new target for therapeutic approaches to preventing scar hyperplasia and accelerating wound healing.     

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。     

Establishment of a long‐term hypertrophic scar model by injection of anhydrous alcohol: A rabbit model

The processes of hypertrophic scar formation are extremely complex, and current animal models have limitations in terms of the complete characterization of lesions. An ideal animal model is indispensable for exploring the complex progression of scar formation to elucidate its pathophysiology and to perform therapeutic testing. This study aimed to establish a long‐term, consistent and easily testable animal model by injecting anhydrous alcohol into the dorsal trunk dermis of rabbits. The rabbits were injected with different amounts of anhydrous alcohol. Anhydrous alcohol was infiltrated into the subcutaneous and superficial fascia. The optimal amount of anhydrous alcohol was determined by measuring the area and thickness of the scar. The typical model was established by determining the optimum dosage, and then we analysed the histological characteristics and fibrosis‐associated protein expression. The dermal scar was generated by treating with 2 ml/kg anhydrous alcohol and displayed histopathologic features that characterize human hypertrophic scarring, including a parallel collagen fibre orientation, dermal and epidermal thickening, broad collagen deposition and the loss of dermal adnexal structures. The expression of fibrotic pan‐markers was also enhanced. Moreover, the scar features and duration were compared between the anhydrous alcohol model and the rabbit ear model. Our results show that injecting anhydrous alcohol in the rabbit model thickened the dermal tissue, stimulated dermal fibroproliferation and resulted in hypertrophic scars with protein and histologic features similar to those seen in humans. Taken together, the findings from this study show that our model could be a feasible and useful tool for further research on the pathogenesis of hypertrophic scars.     

重组人内抑素对兔耳创面瘢痕组织血管内皮生长因子、转化生长因子-β_1和碱性成纤维细胞生长因子表达的影响

目的观察重组人内抑素(rh Endostatin)对兔耳创面瘢痕增生及血管内皮生长因子(VEGF)、转化生长因子β1(TGF-β1)和碱性成纤维细胞生长因子(b FGF)表达的影响,探讨rh Endostatin抑制瘢痕增生的分子机制。方法健康新西兰大耳白兔20只,均分为正常对照组、模型组、生理盐水(NS)对照组、rh Endostatin(5 g/L)治疗组和醋酸曲安奈德(TA,40 g/L)对照组;除正常对照组外其余各组均进行增生性瘢痕动物模型的复制,在兔耳腹侧面制作1cm×1cm大小创面。术后第28天,rh Endostatin治疗组瘢痕皮内注射相应浓度rh Endostatin(100μl),NS对照组注射等量生理盐水,隔日1次,共6次;TA对照组瘢痕块内注入相应浓度曲安奈德(100μl),每周1次,共2次;模型组术后不接受处理。术后第47天摄片并收集瘢痕及正常皮肤标本,应用免疫组织化学方法检测VEGF、TGF-β1和b FGF的表达。结果形态学观察结果显示,术后第47天rh Endostatin治疗组瘢痕皮肤色泽变浅,变软变平,体积减小,与模型组和NS对照组比较有明显差异;免疫组织化学检测结果可见,与模型组和NS对照组相比,rh Endostatin治疗组VEGF和TGF-β1蛋白表达减少,b FGF表达增加,差异均具有统计学意义(P0.01)。结论 rh Endostatin能有效抑制兔耳创面瘢痕增生,其机制可能与rh Endostatin影响VEGF、TGF-β1和b FGF蛋白的表达有关。     

Effects of keratinocyte growth factor-2 (KGF-2) on wound healing in an ischaemia-impaired rabbit ear model and on scar formation

Keratinocyte growth factor-2 (KGF-2), also described as fibroblast growth factor-10 (FGF-10), is a member of the fibroblast growth factor family. KGF-2 shares 57 per cent sequence homology to previously reported KGF-1 (FGF-7). In skin, both growth factors are expressed in the dermal compartment. KGF-1 and KGF-2 bind to the same receptor with high affinity, the KGFR isoform of FGFR2, which is exclusively expressed by epithelial cells. This study examines the in vivo function of topically applied KGF-2 on wound healing using an ischaemia-impaired rabbit dermal ulcer model, in young and aged animals. Histological analysis of the wounds showed that KGF-2 significantly promoted re-epithelialization in both young and old animals. Similar results have been observed with KGF-1 in this model. In addition, KGF-2 enhanced granulation tissue formation in both young and old rabbits, a biological effect not found with KGF-1, suggesting a possible indirect mechanism which enhances neo-granulation tissue formation. Immunohistological staining of day 7 wounds with proliferating cell nuclear antigen (PCNA) antibody demonstrated a significant increase of dermal cell proliferation in KGF-2-treated wounds compared with placebo wounds. These results suggest a mesenchymal–epithelial interaction that is mediated by a paracrine feedback loop of KGF-2. Because of the wound healing impairment observed with ageing, the wound healing response to KGF-2 was also studied in ischaemic wounds of aged animals. Administration of KGF-2 led to significant stimulation of epithelial growth and granulation tissue formation. The effects seen in the old animals were delayed compared with the young animals. Lastly, the effect of KGF-2 was examined in a rabbit model of scar formation. Quantification of scar elevation index showed no significant differences in scar formation when KGF-2 was compared with buffer placebo. Compared with other growth factors, including KGF-1 and TGF-β which have previously been examined in these models, KGF-2 is the most effective and causes no obvious scarring. Copyright © 1999 John Wiley & Sons, Ltd.     

Location of injury influences the mechanisms of both regeneration and repair within the MRL/MpJ mouse

The adult MRL/MpJ mouse regenerates all differentiated structures after through-and-through ear punch wounding in a scar-free process. We investigated whether this regenerative capacity was also shown by skin wounds. Dorsal skin wounds were created, harvested and archived from the same animals (MRL/MpJ and C57BL/6 mice) that received through-and-through ear punch wounds. Re-epithelialization was complete in dorsal wounds in both strains by day 5 and extensive granulation tissue was present by day 14 post-wounding. By day 21, wounds from both strains contained dense amounts of collagen that healed with a scar. The average wound area, as well as alpha-smooth muscle actin expression and macrophage influx were investigated during dorsal skin wound healing and did not significantly differ between strains. Thus, MRL/MpJ mice regenerate ear wounds in a scar-free manner, but heal dorsal skin wounds by simple repair with scar formation. A significant conclusion can be drawn from these data; mechanisms of regeneration and repair can occur within the same animal, potentially utilizing similar molecules and signalling pathways that subtly diverge dependent upon the microenvironment of the injury.     

Regulation of scar formation by vascular endothelial growth factor

Vascular endothelial growth factor (VEGF-A) is known for its effects on endothelial cells and as a positive mediator of angiogenesis. VEGF is thought to promote repair of cutaneous wounds due to its proangiogenic properties, but its ability to regulate other aspects of wound repair, such as the generation of scar tissue, has not been studied well. We examined the role of VEGF in scar tissue production using models of scarless and fibrotic repair. Scarless fetal wounds had lower levels of VEGF and were less vascular than fibrotic fetal wounds, and the scarless phenotype could be converted to a scar-forming phenotype by adding exogenous VEGF. Similarly, neutralization of VEGF reduced vascularity and decreased scar formation in adult wounds. These results show that VEGF levels have a strong influence on scar tissue formation. Our data suggest that VEGF may not simply function as a mediator of wound angiogenesis, but instead may play a more diverse role in the wound repair process.     

生物止血材料医用胶黏合儿童额面部开放性伤口创面的可行性

背景：生物止血材料医用胶在体液、血液作用下的扩散性好,可迅速发生聚合反应,产生较理想的止血、促进愈合等作用。 目的：观察医用胶作为止血材料在儿童额面部开放性伤口创面中的临床应用价值。 方法：选择以生物材料医用胶黏合额面部开放性伤口的1 218例儿童为观察组,以常规丝线缝合额面部开放性伤口的600例儿童为对照组,比较两组伤口愈合时间、术后伤口出血情况、缝线反应、色素沉着情况及瘢痕增生程度。 结果与结论：观察组手术时间、出血量及伤口愈合时间均少于对照组(P < 0.05),有效止血率高于对照组(P < 0.05);观察组中1 215例伤口Ⅰ期愈合,对照组中586例伤口Ⅰ期愈合。随访12个月,观察组瘢痕愈合平整,无线结瘢痕及针眼瘢痕,与临近皮肤肤色相近,美容效果良好;对照组瘢痕较明显,可见线结瘢痕及针眼瘢痕,大部分伤口周围出现红斑、硬结及瘢痕增生。使用生物止血材料医用胶黏合儿童额面部开放性伤口具有良好的生物相容性及美容效果,且使用安全、方便。中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程      

Partial dermal regeneration is induced by biodegradable collagen-glycosaminoglycan grafts

We have sequentially documented the early morphologic events that result in partial regeneration of the adult guinea pig dermis. This phenomenon occurs when a full-thickness skin wound is grafted with a highly specific collagen-glycosaminoglycan (CG) copolymer which has been seeded with autologous dermal and epidermis cells (Yannas IV, Lee E, Orgill DP, Skrabut EM, Murphy GF, Proc Natl Acad Sci USA 86:933-937, 1989). By day 7, ultrastructural analysis disclosed highly organized associations between mononuclear cells and CG fibers involving prominent extension of pseudopod-like processes toward the fiber surface. Spatial organization of cells was not evident in ungrafted wounds. By day 10, more than 50% of the CG grafts had been degraded and extensive neovascularization was observed in various stages of formation. By day 14, dermal fibroblasts in the graft site demonstrated random alignment of long axes, and a minor fraction (less than 10%) exhibited features of myofibroblasts. A majority (greater than 50%) of dermal fibroblasts in ungrafted wounds were identified as myofibroblasts at this time, and their axes were regularly aligned in parallel with the overlying epidermal layer. Scattered CG copolymer fragments were engulfed by macrophages by day 14, and complete dissolution occurred by day 21. Dermal blood vessels formed a discrete, subepidermal plexus oriented parallel to the epidermal plane by days 14 to 17 in grafted wound beds but not in ungrafted ones. Progressive, randomly oriented collagen deposition occurred at graft sites during the 1st year, whereas collagen fibers in ungrafted wounds were aligned in a horizontal plane atypical of a forming scar. By 1 year, the graft sites resembled normal dermis, with well-defined dermal papillae, normal anastomosing superficial vasculature, nerve fibers, and random collagen fiber morphology. Wound sites at this juncture resembled a mature scar, with a flattened dermal-epidermal interface; rare and disorganized vessels and nerves; and collagen fibers parallel to the epidermis. This investigation demonstrates the critical importance of highly specific extracellular matrix in induction of dermal morphogenesis.     

Design and in vivo evaluation of a molecularly defined acellular skin construct: reduction of early contraction and increase in early blood vessel formation

Skin substitutes are of great benefit in the treatment of patients with full thickness wounds, but there is a need for improvement with respect to wound closure with minimal contraction, early vascularisation, and elastin formation. In this study we designed and developed an acellular double-layered skin construct, using matrix molecules and growth factors to target specific biological processes. The epidermal layer was prepared using type I collagen, heparin and fibroblast growth factor 7 (FGF7), while the porous dermal layer was prepared using type I collagen, solubilised elastin, dermatan sulfate, heparin, fibroblast growth factor 2 (FGF2) and vascular endothelial growth factor (VEGF). The construct was biochemically and morphologically characterised and evaluated in vivo using a rat full thickness wound model. The results were compared with the commercial skin substitute IntegraDRT and untreated wounds. The double-layered construct was prepared according to the design specifications. The epidermal layer was about 40 μm thick, containing 9% heparin and 0.2 μg FGF7 mg per layer, localised at the periphery. The dermal layer was 2.5 mm thick, had rounded pores and contained 10% dermatan sulfate+heparin, and 0.7 μg FGF2+VEGF mg per layer. The double-layered skin construct was implanted in a skin defect and on day 7, 14, 28 and 112 the (remaining) wound area was photographed, excised and (immuno) histologically evaluated. The double-layered skin construct showed more cell influx, significantly less contraction and increased blood vessel formation at early time points in comparison with IntegraDRT and/or the untreated wound. On day 14 the double-layered skin construct also had the fewest myofibroblasts present. On day 112 the double-layered skin construct contained more elastic fibres than IntegraDRT and the untreated wound. Structures resembling hair follicles and sebaceous glands were found in the double-layered skin construct and the untreated wound, but hardly any were found in IntegraDRT. The results provide new opportunities for the application of acellular skin constructs in the treatment of surgical wounds.     

Interpenetrating polymer networks containing gelatin modified with PEGylated RGD and soluble KGF: synthesis, characterization, and application in in vivo critical dermal wound

The purpose of this study was to evaluate the biocompatibility and the efficacy in wound healing of a gelatin-based interpenetrating polymer network (IPN) containing poly(ethylene glycol) (PEG)-ylated RGD and soluble KGF-1 (RGD-IPN+KGF). IPNs were applied to full-thickness wounds on a rat model. Wound healing was assessed through histological grading of the host response and percent area contraction at 2 days, 1 week, 2 weeks, and 3 weeks. A control IPN containing unmodified gelatin (unmod-IPN) and a conventional clinical bandage were applied to similar wounds and also evaluated. During the first week of healing, the unmod-IPN and conventional dressing wound showed a greater amount of contraction than that of RGD-IPN+KGF. However, by 3 weeks the extent of wound contraction was comparable between treatments. The RGD-IPN+KGF treated wound demonstrated lower macrophage and fibroblast densities at 3 weeks as compared to unmod-IPN treated wounds. RGD-IPN+KGF acted as a tissue scaffold while preventing the entry of foreign bodies, advantages not seen with the conventional dressing. The extent of cellularity and extracellular matrix organization was higher for wounds healed with RGD-IPN+KGF than those healed with unmod-IPN. These results indicate that both soluble and immobilized bioactive factors can be incorporated into our IPN platform to enhance the rate and the quality of dermal wound healing.     

Diminished type III collagen promotes myofibroblast differentiation and increases scar deposition in cutaneous wound healing

The repair of cutaneous wounds in the postnatal animal is associated with the development of scar tissue. Directing cell activities to efficiently heal wounds while minimizing the development of scar tissue is a major goal of wound management and the focus of intensive research efforts. Type III collagen (Col3), expressed in early granulation tissue, has been proposed to play a prominent role in cutaneous wound repair, although little is known about its role in this process. To establish the role of Col3 in cutaneous wound repair, we examined the healing of excisional wounds in a previously described murine model of Col3 deficiency. Col3 deficiency (Col3+/-) in aged mice resulted in accelerated wound closure with increased wound contraction. In addition, Col3-deficient mice had increased myofibroblast density in the wound granulation tissue as evidenced by an increased expression of the myofibroblast marker, α-smooth muscle actin. In vitro, dermal fibroblasts obtained from Col3-deficient embryos (Col3+/- and -/-) were more efficient at collagen gel contraction and also displayed increased myofibroblast differentiation compared to those harvested from wild-type (Col3+/+) embryos. Finally, wounds from Col3-deficient mice also had significantly more scar tissue area on day 21 post-wounding compared to wild-type mice. The effect of Col3 expression on myofibroblast differentiation and scar formation in this model suggests a previously undefined role for this ECM protein in tissue regeneration and repair.     

Tumstatin对兔耳增生性瘢痕的抑制作用

目的 探讨肿瘤抑素(Tumstatin)对兔耳瘢痕组织生长情况的影响.方法 建立兔耳增生性瘢痕模型,用Tumstatin对兔耳腹侧建立的增生性瘢痕模型通过在体局部注射进行干预,随机设立Tumstatin治疗组、Tumstatin预防治疗组、曲安奈德对照组、生理盐水对照组;停止药物注射21天后各组同时于每只兔的双侧对称部位取材瘢痕组织,每一取材瘢痕组织均分成同样大小的四等份,分别进行组织形态学观察、CD34免疫组化方法测定血管密度的变化、观察血管内皮细胞与成纤维细胞凋亡的变化情况.结果 Tumstatin预防治疗组和Tumstatin治疗组中,新生毛细血管密度、内皮细胞活性以及成纤维细胞数量都较曲安奈德和生理盐水对照组明显降低,差异有统计学意义(P<0.05).结论 Tumstatin能够较曲安奈德更明显地抑制增生性瘢痕的生长,为Tumstatin用于防治增生性瘢痕的可行性提供了初步的理论依据.     

大鼠背部脊柱两侧全层皮肤圆形创面增生性瘢痕愈合过程中臭氧的作用**☆

背景：预防硬膜外瘢痕的形成,可减少腰椎手术失败综合征的发生。臭氧应用于腰椎间盘突出症的治疗已取得较好的临床效果。 目的：观察臭氧对大鼠伤口瘢痕愈合过程的影响。 方法：外科切口法制备大鼠背部脊柱两侧圆形全层皮肤创面增生性瘢痕模型,分为3组,纯氧组及臭氧组分别注射纯氧及30~40 mg/L臭氧,总量均为5 mL,空白组不注射任何药物,每周2次,4周后取瘢痕/肉芽组织标本,利用苏木精-伊红染色及免疫组化方法,对比观察各组标本瘢痕/肉芽组织外观及肿瘤坏死因子α、碱性成纤维细胞生长因子表达的变化。 结果与结论：与空白组及纯氧组相比,臭氧组愈后瘢痕面积较小,上皮生成较多,炎性细胞浸润较少,胶原纤维较纤细,且断裂较多;臭氧组肿瘤坏死因子α阳性细胞数较低(P < 0.01),碱性成纤维细胞生长因子阳性细胞数较高(P < 0.01)。提示臭氧通过其抗炎作用,减少炎性细胞浸润,并可通过抑制成纤维细胞及巨噬细胞释放的肿瘤坏死因子α以及提高碱性成纤维细胞生长因子的表达,减少胶原的过度合成,从而起到抑制肉芽组织炎症及瘢痕组织增生的作用。关键词：臭氧;瘢痕;伤口愈合;肿瘤坏死因子α;碱性成纤维细胞生长因子 缩略语注释：TNF-α: tumor necrosis fact-alpha,肿瘤坏死因子α;bFGF: basic fibroblast growth factor,碱性成纤维细胞生长因子 doi:10.3969/j.issn.1673-8225.2012.15.012     

Dextran derivatives modulate collagen matrix organization in dermal equivalent

Dextran derivatives can protect heparin binding growth factor implied in wound healing, such as transforming growth factor-beta1 (TGF-beta1) and fibroblast growth factor-2 (FGF-2). The first aim of this study was to investigate the effect of these compounds on human dermal fibroblasts in culture with or without TGF-beta1. Several dextran derivatives obtained by substitution of methylcarboxylate (MC), benzylamide (B) and sulphate (Su) groups were used to determine the effects of each compound on fibroblast growth in vitro. The data indicate that sulphate groups are essential to act on the fibroblast proliferation. The dextran derivative LS21 DMCBSu has been chosen to investigate its effect on dermal wound healing process. Fibroblasts cultured in collagenous matrices named dermal equivalent were treated with the bioactive polymer alone or associated to TGF-beta1 or FGF-2. Cross-sections of dermal equivalent observed by histology or immunohistochemistry, demonstrated that the bioactive polymer accelerates the collagen matrices organization and stimulates the human type-III collagen expression. This bioactive polymer induces apoptosis of myofibroblast, property which may be beneficial in treatment of hypertrophic scar. Culture media analyzed by zymography and Western blot showed that this polymer significantly increases the secretion of zymogen and active form of matrix metalloproteinase-2 (MMP-2), involved in granulation tissue formation. These data suggest that this bioactive polymer has properties which may be beneficial in the treatment of wound healing.     

The effect of multifunctional polymer-based gels on wound healing in full thickness bacteria-contaminated mouse skin wound models

We determined whether a two-part space-conforming polyethylene glycol/dopa polymer-based gel promoted healing of contaminated wounds in mice. This silver-catalysed gel was previously developed to be broadly microbiocidal in vitro while being biocompatible with human wound cell functioning. Full-thickness wounds were created on the backs of mice. The wounds were inoculated with 10(4) CFU of each of four common skin wound contaminants, Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter baumanii and Clostridium perfringens. The wounds were then treated with our multifunctional polymer-based gel, the commercially available NewSkin product, or left to heal untreated. The untreated wounds were overtly infected, and presented detectable bacterial loads over the entire 21-day healing period, while the gel and NewSkin groups presented significantly smaller rises in bacterial levels and were cleared of detectable colonies by the third week, with the gel group clearing the bacteria earlier. While all three groups healed their wounds, the polymer-based gel-treated group demonstrated significantly earlier re-epithelialization and dermal maturation (P<0.05). This was reflected in a quick regain of tensile strength. This accelerated dermal maturation and regain in strength was noted in mice treated with the polymer-based gel when compared to wound treated with the commercially available Aquacel-Ag dressing (P<0.05). What distinguishes the polymer-based gel from these other products is that it is incorporated within the healing wound. These preclinical studies show that the anti-microbial polymer gel not only supports but also accelerates healing of bacterially contaminated wounds.     

Effects of subcutaneous injection of ozone during wound healing in rats

Fibroblast growth factor 2 (FGF2) regulates the wound repair process and it is secreted by inflammatory and endothelial cells, and by myofibroblasts. This study aimed to establish the expression patterns of FGF2 and myofibroblastic differentiation during wound healing in rats treated with subcutaneous ozone injection. We created full-thickness excisional wounds in rats, and the healing process was analyzed through morphometric analyses and digital quantification of immunoreactivity of smooth muscle actin and FGF2. Ozone therapy-treated wounds presented granulation tissue with a reduced number of inflammatory cells and greater dermal cellularity, and intense collagen deposition. FGF2 immunoreactivity, microvessel density, and amount of myofibroblasts were significantly higher in treated wounds compared to controls. In conclusion, it was demonstrated that subcutaneous injections of ozone accelerate and ameliorate wound repairing process. Moreover, injectable ozone therapy’s action mechanism may be associated with FGF2 overexpression.     

Higher numbers of autologous fibroblasts in an artificial dermal substitute improve tissue regeneration and modulate scar tissue formation

Cultured skin substitutes are increasingly important for the treatment of burns and chronic wounds. The role of fibroblast numbers present in a living-skin equivalent is at present unknown. The quality of dermal tissue regeneration was therefore investigated in relation to the number of autologous fibroblasts seeded in dermal substitutes, transplanted instantaneously or precultured for 10 days in the substitute. A full-thickness porcine wound model was used to compare acellular dermal substitutes (ADS) with dermal substitutes seeded with fibroblasts at two densities, 1x10(5) (0-DS10) and 5x10(5) cells/cm(2) (0-DS50), and with dermal substitutes seeded 10 days before operation at the same densities (10-DS10 and 10-DS50) (n=7 for each group, five pigs). After transplantation of the dermal substitutes, split-skin mesh grafts were applied on top. Wound healing was evaluated blind for 6 weeks. Cosmetic appearance was evaluated and wound contraction was measured by planimetry. The wound biopsies taken after 3 weeks were stained for myofibroblasts (alpha-smooth muscle actin), and after 6 weeks for scar tissue formation (collagen bundles organized in parallel and the absence of elastin staining). Collagen maturation was investigated with polarized light. For wound cosmetic parameters, the 10-DS50 and 0-DS50 treatments scored significantly better than the ADS treatment, as did the 10-DS50 treatment for wound contraction (p<0.05, paired t-test). Three weeks after wounding, the area with myofibroblasts in the granulation tissue, determined by image analysis, was significantly smaller for 0-DS50, 10-DS10, and 10-DS50 than for the ADS treatment (p<0.04, paired t-test). After 6 weeks, the wounds treated with 0-DS50, 0-DS10, and 10-DS50 had significantly less scar tissue and significantly more mature collagen bundles in the regenerated dermis. This improvement of wound healing was correlated with the higher numbers of fibroblasts present in the dermal substitute at the moment of transplantation. In conclusion, dermal regeneration of experimental full-skin defects was significantly improved by treatment with dermal substitutes containing high numbers of (precultured) autologous fibroblasts.