An in vivo critically colonised wound model with dysbiotic wound microbiota

In critically colonised wounds, many of the signs of infection are often absent, and delayed healing may be the only clinical sign. The prevention of critical colonisation is important, but its pathophysiology has not yet been elucidated. We have previously reported that dysbiotic microbiota dissimilar to the peri-wound skin microbiota may develop in critically colonised wounds. To investigate the role of dysbiotic microbiota, this study aimed to develop a critically colonised wound model by transplantation of dysbiotic microbiota. To transplant microbiota, a bacterial solution (dysbiosis group) or with Luria-Bertani medium (commensal group) was inoculated to full-thickness wounds of rats. The bacterial solution was prepared by anaerobically culturing bacteria from donor rats on an artificial dermis in Luria-Bertani medium for 72 hours. As a result, the degree of the change in the microbial similarity between pre- and post-transplantation of microbiota was significantly higher in the dysbiosis group (P < .001). No signs of infection were observed in any rat in either group. The wound area in the dysbiosis group was significantly larger (P < .001), and there was a significant infiltration of neutrophils (P < .001). All rats of the dysbiosis group represented the clinical features of critically colonised wounds. Furthermore, there were significantly fewer regulatory T cells in the wounds of the dysbiosis group. This is the first study to develop a novel animal model that represents the clinical features of critically colonised wounds and will be useful in investigating the pathogenesis of critical colonisation via regulatory T cells.

A Comparative Study of the Effects of Nigella sativa Oil Gel and Aloe Vera Gel on Wound Healing in Diabetic Rats

Clinicians and wound care nurses in Indonesia usually use Nigella sativa oil (NSO) gel and aloe vera (AV) gel to treat diabetic ulcers. However, there are no studies directly comparing the effects of NSO and AV gels on wound healing, so it is unknown which of these 2 plants is better at promoting wound healing in diabetic ulcers. If the comparative efficacy between these 2 gels was known, it would be important evidence favoring the clinical use of one or the other product in Indonesia. The aim of this study was to investigate and compare the effectiveness of NSO and AV gels on wound healing in a rat model of diabetic ulcers. This experimental study involved 3 groups: NSO gel, AV gel, and controls. Our study showed that from day 5 onward, necrotic tissue and inflammation decreased in the AV gel group compared with the other groups. The wound areas on days 6 (P = .020) and 7 (P = .021) were significantly smaller in the AV gel group than in the NSO gel group. Reepithelialization was also better in the AV gel group than in the other groups. This is the first study to compare the effects of AV and NSO gels on wound healing in diabetic ulcers. Our study indicates that the AV gel is better than the NSO gel. Therefore, it is recommended that clinicians and wound care nurses use AV gel instead of NSO gel for the topical treatment of diabetic ulcers.

A Comparative Study of the Effects of Vibration and Electrical Stimulation Therapies on the Acceleration of Wound Healing in Diabetic Ulcers

Introduction: Diabetic ulcers accompanied by ischemia is difficult to treat. Such ulcers require therapy that can improve the blood flow. Previous studies have revealed that two therapies could improve blood flow and accelerate the healing of diabetic ulcers; vibration and electrical stimulation (ES). However, it is unknown which of these two therapies is best at accelerating wound healing in diabetic ulcers. The purpose of this study was to compare both therapies in relation to accelerating the wound healing of diabetic ulcers. Methods: This study was an experimental study involving diabetic rats. The rats were divided into two groups: vibration and ES. Vibration and ES were applied for 10 minutes per day for 7 days. Wound size, inflammation, intensity of fibroblast infiltration, area of necrosis and degree of re-epithelialisation were compared. The difference in wound size was analysed using an independent t-test, while the histological data were analysed using a Mann-Whitney U-test. Results: On day 5 onwards, there was a thin slough in the ES group which was not present in the vibration group. Day 4 onwards and the wound size was significantly smaller in the vibration group than in the ES group. The intensity of inflammation was significantly less, and the degree of fibroblast infiltration was significantly higher in the vibration group compared with the ES group. Re-epithelialisation was more advanced in the vibration group than the ES group. Conclusions: Our study revealed that wound healing in diabetic ulcers following vibration was better than after ES. We suggest that nurses should use vibration rather than ES in clinical settings.

Topical Administration of Acylated Homoserine Lactone Improves Epithelialization of Cutaneous Wounds in Hyperglycaemic Rats

Clinicians often experience delayed epithelialization in diabetic patients, for which a high glucose condition is one of the causes. However, the mechanisms underlying delayed wound closure have not been fully elucidated, and effective treatments to enhance epithelialization in patients with hyperglycaemia have not been established. Here we propose a new reagent, acylated homoserine lactone (AHL), to improve the delayed epithelialization due to the disordered formation of a basement membrane of epidermis in hyperglycaemic rats. Acute hyperglycaemia was induced by streptozotocin injection in this experiment. Full thickness wounds were created on the flanks of hyperglycaemic or control rats. Histochemical and immunohistochemical analyses were performed to identify hyperglycaemia-specific abnormalities in epidermal regeneration by comparison between groups. We then examined the effects of AHL on delayed epithelialization in hyperglycaemic rats. Histological analysis showed the significantly shorter epithelializing tissue (P < 0.05), abnormal structure of basement membrane (fragmentation and immaturity), and hypo- and hyperproliferation of basal keratinocytes in hyperglycaemic rats. Treating the wound with AHL resulted in the decreased abnormalities of basement membrane, normal distribution of proliferating epidermal keratinocytes, and significantly promoted epithelialization (P < 0.05) in hyperglycemic rats, suggesting the improving effects of AHL on abnormal epithelialization due to hyperglycemia.

Novel models for bacterial colonization and infection of full-thickness wounds in rats

An animal model is needed to study the pathophysiology of wound infections; however, an animal model that is reproducible and clinically relevant has not previously been available. In addition, an animal model of wound colonization generated in a manner similar to the wound infection model would be useful. Here, we describe new animal models of the wound infection continuum for the characterization of essential host-pathogen relationships. We determined the conditions needed to establish rat models of stable wound colonization and infection, without the use of disturbing factors (e.g., foreign bodies or induction of diabetes mellitus). We found that the age of the rats, bacterial inoculum size, and wound location were important elements in generating reproducible, obvious, spreading wound infections. We inoculated approximately 6-month-old rats with 2.06 × 10(9) or 4.12 × 10(9) colony-forming units of Pseudomonas aeruginosa to generate the wound colonization and wound infection models, respectively. Wounds were made 2 cm cranial to the greater trochanter. These clinically relevant and highly reproducible animal models can be used to investigate the mechanisms of wound infection and monitor the effect of therapeutic agents in vivo.

Impaired aquaporin 3 expression in reepithelialization of cutaneous wound healing in the diabetic rat

Impaired cutaneous wound healing is a serious complication of diabetes mellitus (DM). Currently, little is known about reepithelialization in DM. However, recent studies identified aquaporin 3 (AQP3), a transmembrane protein that functions as a pore-like passive transporter, to be a key molecule in cutaneous epidermal wound healing. AQP3 expression is downregulated in response to tumor necrosis factor-alpha (TNF- α). Given that systemic TNF-α levels are functionally connected to impaired healing in diabetic mice and that both diabetic and Aqp3-deficient animals exhibit impaired reepithelialization, the authors hypothesized that impaired AQP3 expression might contribute to diabetes-impaired wound healing. In the present study, the authors examined AQP3 expression in the regenerating epidermis during cutaneous full thickness wound healing and in intact skin of a streptozotocin-induced diabetic rat model. Aqp3 messenger RNA expression levels were decreased in wounds of DM rats compared to controls. Immunohistochemical analysis showed an absence of AQP3 in the stratum spinosum of the regenerating epidermis in the DM group, whereas the stratum basale was positive for AQP3 in both groups. In summary, these findings suggest that there may be a relationship between impaired AQP3 expression and diabetes-delayed reepithelialization. Thus, future nursing studies should focus on this mechanism in diabetic wound healing.