Effect of sildenafil on wound healing: an experimental study

Purpose  

We aimed to investigate the effect of sildenafil on the healing process of abdominal wall wound in rats.     

Effect of rapamycin on wound healing: an experimental study

The aim of this study was to investigate the effects of rapamycin (RAPA) on the healing of bladder and abdominal wound closures. Fourteen male Sprague Dawley rats were randomized to receive either RAPA (3 mg/d) or placebo. A midline laparotomy was performed. The bladder was cut and closed with 4-0 Vicryl in a double layer. The fascia was closed with 0 nylon suture, and the skin closed with a subcuticular 2-0 nylon suture. The mean RAPA level was 9.1 ng/mg. Eosinophil and neutrophil infiltration, and the presence and degree of myofibroblast proliferation were significantly higher in the bladder, fascia, and dermis of the control group. Lymphocyte infiltration was similar in each group. Mean microvessel density as well as the percentage of cells expressing vascular endothelial growth factor in the bladder, fascia, and dermis were significantly lower among the RAPA group. Both proliferating cell nuclear antigen labeling indices for inflammatory cells in the fascia, dermal fibroblasts, and epithelial cells in the placebo group were significantly higher. No difference was observed for hydroxyproline levels in both the bladder and fascia between the groups. In conclusion, we found that RAPA treatment affected all steps of the wound healing process by decreasing the inflammatory cell number, angiogenesis, and myofibroblast proliferation, so the wound healing process was delayed and consequently the tensile strength of the wound decreased.     

Effect of obstructive jaundice on wound healing. An experimental study in rats

The effect of obstructive jaundice on wound healing was investigated in an experimental study of gastric and abdominal wounds in rats after ligation and division of the common bile duct. The healing of a parietal defect in these animals showed histologic evidence of delayed healing compared with controls. The bursting strength of the abdominal incision was also decreased, but not that of the stomach. These findings suggest that the biochemical changes in the wounds of jaundiced animals interfere with wound repair. The possible causes of this delay in healing and its clinical implications require further investigation.     

Impact of 970 nm photobiomodulation therapy on wound healing in cellular models of hidradenitis suppurativa

Lasers in Medical Science -     

Effect of photobiomodulation therapy on radiodermatitis in a mouse model: an experimental animal study

Lasers in Medical Science - This study aimed to evaluate the effect of photobiomodulation (PBM) for prevention of radiodermatitis in an irradiated mouse model and compare the efficacy of PBM using...     

Influence of insulin therapy on burn wound healing in rats

BACKGROUND: Insulin is proposed as a therapy for suppressing muscle wasting after burn trauma although the long-term effects of this therapy on wound healing are not yet known. The present study was designed to investigate the effect of systemically administered insulin therapy on burn wound healing. MATERIALS AND METHODS: Young rats weighing 80-150 g were subjected to 15-20% total body surface area burn injury on their shaved dorsum. The insulin dosage was increased over the first 3 days in each rat from 0.25 U (Day 1), 0.5 U (Day 2), and 1.0 U (Day 3) per 100 g body wt. The rats were euthanized at the fourth or fifteenth day postinjury. Skin sections were analyzed by histochemistry and quantitative polarization microscopy. RESULTS: Histology showed a decreased number of inflammatory cells and increased vasodilation in the insulin-treated animals at Day 4 relative to untreated rats; at Day 15 there was increased reepithelialization. Quantitative analysis using polarization microscopy and picrosirius red staining showed an increased collagen deposition in wounds by Day 4 in insulin-treated rats relative to untreated burn controls. CONCLUSION: These results indicate that insulin induces accelerated wound healing associated with diminished inflammation and increased collagen deposition.     

Effect of fibronectin therapy and fibronectin deficiency on wound healing: a study in rats

Rats with standardized 3rd-degree burns of 1% body surface were treated intraperitoneally with different doses of human fibronectin or swine gelatin immediately after injury and on the following days. Controls received bovine albumin or no further treatment. Wound healing was assessed by planimetry (days 0, 2, and 7); additionally, plasma fibronectin was determined (days 3 and 7). On day 3 fibronectin levels were significantly elevated after albumin and the highest dosage of fibronectin (3 X 16 mg) and decreased after gelatin and the lowest dosage of fibronectin (3 X 4 mg). Wound healing was neither affected by albumin nor by human fibronectin, but it was significantly impaired by gelatin-induced lack of fibronectin. The data support the opinion that fibronectin is an essential factor for the post-traumatic clearance of gelatin-like tissue debris via the reticuloendothelial system (RES). Overload by gelatin results in fibronectin deficiency and RES dysfunction with risks of infection and poor wound healing.     

去神经支配对大鼠创面愈合的影响

目的通过制备去神经支配大鼠创面模型,观察去神经大鼠创面愈合率、创面血管和皮肤增殖改变情况,为去神经创面Ⅹ合机制提供理论依据。方法分离并切断SD大鼠胸9～腰1右侧脊神经,造模后在背部对称制作两个直径为1.0cm的圆形创面,分别观察两侧创面愈合时间、创面大体和组织形态学、创面细胞增殖活性、创面修复过程中血管再生情况,并对数据进行统计学分析。结果实验组愈合时间在4周,对照组为3周;实验组创面上皮化速度慢于对照组;实验组愈合表皮层较薄,上皮细胞大小不一;愈合时真皮和表皮层细胞增殖活跃,2～4周时实验组增殖活性低于对照组(P0.05);创面微血管主要分布于真皮层,密度随Ⅹ合时间增加,但2～4周实验组表现较对照组弱(P0.05)。结论去神经后皮肤创面细胞增殖低下,愈合时间延长,血管再生现象受到抑制。     

Effect of supplemental zinc on wound healing in rats

Two experiments were carried out to determine the effect of supplemental oral zinc on wound healing in a normal rat. No evidence of beneficial effects was found. Measured wounds healed at the same rate, and the wound hydroxyproline level tended to be lower in the animals receiving zinc. There was also no evidence that the rat even incorporates excess zinc in tissues.     

Effect of plasma fibronectin on the incisional wound healing in rats

BACKGROUND: Abdominal wall repair after celiotomy is important because insufficient incisional wound strength results in wound failures such as fascial dehiscence and herniation. Plasma fibronectin (pFn) has been shown to play an important role in wound healing. The purpose of this study was to investigate whether pFn improves incisional wound healing in a rat skin incision and celiotomy model. METHODS: Rats underwent a linear skin incision in the dorsal plane or a full-thickness incisional wound (celiotomy) in the abdominal wall. The same operative procedures were performed on rats whose pFn levels were reduced by antirat pFn serum. The wounds were sutured, and purified human pFn or albumin was given intravenously. RESULTS: After the celiotomy, pFn levels decreased immediately and reached a minimum at 3 h after incision. A single injection of pFn (10 mg/kg) significantly increased the breaking strength of the skin and the bursting pressure of the abdominal wall. The amount of hydroxyproline in the skin incisional wound with pFn was significantly greater than with an injection of albumin as control. In rats with pFn levels decreased by antirat pFn serum, a single administration of pFn significantly increased the breaking strength of the skin and the bursting pressure of the abdominal wall compared to a control injection of albumin. CONCLUSIONS: It is important for wound healing to maintain sufficiently high levels of pFn. A single intravenous injection of pFn after celiotomy may be useful in the prevention of fascial dehiscence and herniation.     

Effect of melatonin on wound healing in normal and pinealectomized rats

Melatonin usage is increasing gradually, but reports of its effects on wound healing are inconsistent. It has been shown that the hormone is synthesized in and secreted from the gastrointestinal system independently of the pineal gland. We have investigated, by means of a comparative study on the healing of incision and anastomotic wounds, whether melatonin has an effect on wound healing independent of the pineal gland. Rats were divided in five groups (n = 10), all of which were subjected to small intestine anastomosis. The first group (control) was otherwise untreated. Exogenous melatonin was given to the rats in second group. The calvaria was opened then closed in the third group (sham operated), whereas the fourth group was pinealectomized and the fifth group were pinealectomized and then treated with melatonin. After anastomosis bursting pressures and incision wound breaking strength were measured on the 7th postoperative day, tissue hydroxyproline levels were determined, and histopathological investigation was performed. It was found that while collagen deposition and epithelization increased concurrently in incision wounds after pinealectomy, only collagen deposition increased at the anastomosis line. Exogenous melatonin decreased collagen synthesis and epithelium proliferation and had negative effects on wound healing in both normal and pinealectomized rats.     

Effect of ultraviolet therapy on rat skin wound healing

Ultraviolet (UV) light therapy has been suggested as a treatment for pressure sores and crural ulcerations even though controlled trials are few. Therefore, the effect of UV light therapy on wound healing was studied in rat skin. A dose-dependent, significant improvement in the diminution of wound size was found between 4 and 15 days in wounds treated with UV as compared with untreated control wounds in the opposite side of the same animals. Wound closure, however, did not occur earlier in the treated wounds. UV had a marked warming effect; warmth alone without UV had no effect on wound healing. No significant difference was found in the tensile strength of UV-treated wounds at 7 and 15 days when compared with untreated wounds. Moreover, the intensity of the inflammation was equal in both treated and control wounds when studied histologically. We did not find any effect on clinical infection rate or bacterial colonization of the wounds. Although UV therapy seems to have an effect on wound healing in rat skin the present results are rather nonsupportive of the clinical benefits that are expected from this kind of treatment.     

Importance of dehydration in anastomotic and subcutaneous wound healing: an experimental study in rats.

OBJECTIVE: To find out if preoperative and postoperative dehydration adversely affect anastomotic and subcutaneous healing. DESIGN: Randomized study. MATERIAL: 18 Wistar rats. INTERVENTIONS: Dehydration established in nine rats by withdrawal of food and water for 24 hours before operation, and by injections of frusemide twice daily. Laparotomy and division of intestine 5-8 cm from the ileocaecal valve. Implantation of expanded polytetrafluoroethylene (ePTFE) tubes in the backs of the necks. All rats killed after five days. MAIN OUTCOME MEASURES: Measurements of weight loss and of hydroxyproline per centimetre in the ePTFE tubes and standardized biopsy specimens of the intestine. Presence of anastomotic dehiscence at necropsy. RESULTS: Preoperative and postoperative dehydration caused a 24% weight loss in the experimental group on day 5 compared with 8% in the control group. Dehydrated animals accumulated less collagen in the ePTFE tubes than control animals (p less than 0.05). There were three anastomotic breakdowns in the dehydrated group compared with one in the control group. There was a loose but significant correlation between collagen accumulation in the anastomoses and the weight of the animal (r = 0.5, p less than 0.05). CONCLUSION: Preoperative and postoperative dehydration has a deleterious effect on subcutaneous, and to a lesser extent on anastomotic healing in rats.     

Jaundice and wound healing: an experimental study.

Obstructive jaundice was induced in rats by ligation and division of the common bile duct. The healing of a standard gastric incision and a parietal peritoneal defect in these animals showed histological evidence of delayed healing compared with controls. The bursting strength of the abdominal incision was also lowered, but not that of the stomach, probably because of the adhesions which reinforced the gastric incisions. Angiography did, however, reveal delay in angiogenesis in the gastric wounds of jaundiced animals. The possible causes of this delay in healing and its clinical implications require further investigations.     

Light therapy by blue LED improves wound healing in an excision model in rats

Background

Low level light therapy (LLLT) is an attractive alternative to enhance wound healing. So far most studies are performed with red or infrared irradiation. However, we recently showed that blue light (470 nm) can significantly influence biological systems, improving perfusion by release of nitric oxide from nitrosyl complexes with haemoglobin in a skin flap model in rats. Here, we compared the effects of blue and red low level light by light-emitting diodes (LEDs) on in vivo wound healing in an excision wound model in rats.

Methods

Circular excision wounds were surgically created on the dorsum of each rat. Excisions on either the left or right side were illuminated post-OP and on five consecutive days for 10 min by LED at 470 nm or 630 nm with an intensity of 50 mW/cm², while protecting the contralateral side from exposure. In the control group, neither side was illuminated. On day 7 post-OP, we analysed planimetric and histological parameters, as well as expression of keratin-1, keratin-10 and keratin-17 on mRNA level.

Results

Illumination substantially influenced wound healing. Blue light significantly decreased wound size on day 7, which correlated with enhanced epithelialisation. Light also affected mRNA expression. Both wavelengths decreased keratin-1 mRNA on day 7 post-OP, while keratin-10 mRNA level was elevated in both light treated group compared to control. Keratin-17 mRNA was also elevated in the red light group, but was unchanged in the blue light group.

Conclusion

In contrast to previous studies, we showed that also blue light significantly influences wound healing. Furthermore, our data suggest that light therapy can play an important role in normotrophic wound healing by affecting keratin expression. Illumination would provide an easily applicable, safe and cost-effective treatment of surface wounds.     

不同浓度法舒地尔促进皮肤创面愈合作用的研究

目的：观察法舒地尔（HA1077）促进创面愈合的效果,并探讨HA1077与创面愈合的量效关系,寻找出促进创面愈合的最佳剂量。方法：18只Wistar大鼠背部左右两侧致直径为2cm的圆形皮肤缺损。随机3只动物6个创面为一组,分为6组,分别给予10、20、40、80和160μmol/L盐酸法舒地尔和生理盐水（对照组）创面喷洒,每个创面0.5ml,隔日创面追加喷洒。实验3、7、10d计算伤口面积,实验10d取创面组织,观察组织学变化。结果：各组大鼠创面面积随伤后时间延长而逐渐缩小,20μmol/L组创面面积明显小于同时间点其他各组,除实验7d与80μmol/L组创面面积比较差异无显著性外,其余各时间点差异均有显著性（P〈0.05）。病理学变化显示,创伤后10d,应用20μmol/L法舒地尔组创面新生肉芽组织生长及新生表皮生长速度明显优于其他各组。结论：HA1077可促进皮肤缺损创面愈合,以20μmol/LHA1077效果更为明显。