[Show abstract][Hide abstract]ABSTRACT: The demand for scaffolds comprised of natural materials such as collagen has increased in recent years. However, many scaffolds rely on chemical or physical modifications in order to comply with the necessary requirements for biomedical engineering. We evaluated the in vivo biocompatibility and biodegradation of a novel, thin, mechanically stable and chemically non-crosslinked collagen cell carrier (CCC). CCC was implanted subcutaneously into 25 adult Lewis rats and biopsies were taken on days 7, 14, 21, 42, and 84 after surgery. For histological analysis, paraffin sections of implanted skin were immunolabelled for CD68 and stained by haematoxylin-eosin and Masson-Goldner's trichrome method. Macroscopic analysis of skin surface during wound healing process showed a normal physiological reaction. Biodegradation of CCC was completed 42 days after subcutaneous implantation. Histological evaluation revealed no evidence of encapsulation, scar formation, or long term vascularisation and inflammation. The collagen type I based biomaterial demonstrated a high in vivo biocompatibility, low irritability, complete resorption and replacement by autologous tissue. The in vivo biocompatibility and degradation behaviour encourage for further evaluation of CCC in surgical applications and regenerative medicine.
No preview · Article · Apr 2014 · Journal of Biomedical Materials Research Part A
[Show abstract][Hide abstract]ABSTRACT: Split-thickness skin grafting is often associated with poor skin quality. In this context, a new collagen cell carrier (CCC), as an underlayment in split skin graft (SSG) transplantation for covering tissue defects in rats, has been evaluated as an improving agent.
Twenty-eight full-thickness wounds were covered with SSGs, applying the CCC as an underlayment in 14 rats and using SSG transplantation alone in control group. Postgraft skin areas were assessed using an instrument that measures mechanical properties of skin. Three parameters were considered for skin elasticity analysis: total skin deviation (R0), gross elasticity (R2) and viscoelasticity (R8). Measurements were performed every 10 days for 80 days after grafting. Biopsies were taken subsequently for histologic evaluation.
The results demonstrated significantly superior elasticity values in CCC-supplemented SSGs in terms of gross elasticity and viscoelasticity (R2/R8) starting from day 60 after grafting to the end of the measuring period. There was no histologic evidence of inflammation, adverse host tissue reaction, or scar tissue formation.
Split skin grafting is associated with poor dermal quality, but CCC may offer unique opportunities in complex wound management in terms of skin graft quality improvement.
No preview · Article · May 2012 · Dermatologic Surgery
[Show abstract][Hide abstract]ABSTRACT: Literature reviews show numerous options for anesthesia in the small laboratory animals. Many methods are associated with complications, such as high technical effort, difficult monitoring, respiratory and cardiovascular depression, and prolonged sedation. In the present study, we report first time results after repeated use of an intraperitoneal combined anesthesia with a high tolerability.
Three hundred and seventy-four anesthesias were performed on 38 adult male Lewis rats (280-460 g). Each animal was anesthetized repeatedly over a period of three months, using an intraperitoneal combination of Fentanyl-Medetomidine and Midazolam (FMM). The time required for the animals to lose ear pinch response and the ability to perform a righting and pedal withdrawal reflex was measured. For evaluation of the clinical state, a four-point vitality scale was developed. The anesthesia was antagonized with Naloxone, Flumazenil, and Atipamezole (s.c.).
The animals lost all three reflex responses within 5 (± 2.4) min of injection. Without antagonism of anesthesia, the ear pinch response returned on average within 125 (± 21.5) min. After antagonism of anesthesia, the rats needed 5 (± 2.9) min to regain all three reflex responses. No significant differences of vitality-index were measured after repeated use of FMM during the investigation period.
A repeatable and secure anesthesia is indispensable for any experimental studies that require multiple anesthesia of a single animal. Intraperitoneal combination of FMM provides an adequate procedure to induce a well tolerable, repeatable state of anesthesia, which conforms to all the necessary requirements for laboratory rats.
No preview · Article · Apr 2012 · Journal of Investigative Surgery
[Show abstract][Hide abstract]ABSTRACT: There is a broad range of expensive temporary wound dressings that promise better results in wound management. The aim of this study was to compare two commonly used temporary dressings for the treatment of partial-thickness wounds in a rat model.
Forty-two partial thickness wounds were created on the back of Lewis rats and treated with the dressings; control wounds remained without treatment. Wound size was determined daily by measuring the scabbed area. Three months after the wounds were created, skin elasticity was measured and a histologic evaluation was performed.
Wound appearance in the animals in the treated groups did not differ significantly. Wound closure was slower in the control group than in the dressing groups. There was no histologic evidence of inflammation and no suggestion of epidermal changes in any group.
Using both skin dressings, we observed satisfying results without any significant differences. Because of rising health care expenses, cost should play an essential role in the clinical application of these dressings.
No preview · Article · Mar 2012 · Dermatologic Surgery
[Show abstract][Hide abstract]ABSTRACT: Harvesting split skin grafts in rodents has proven to be challenging, as the presence of panniculus carnosus tissue in rodent skin causes high flexibility and mobility of the upper skin layer. Thus, fixation is indispensable for granting precise manipulation during the grafting process. All techniques established in the literature achieve stability by dissecting a subcutaneous pocket beneath the panniculus carnosus. In this article, the authors present a method that excludes inflicting additional wounds other than that to the donor site but takes advantage of the elasticity of rat skin.
A customized sturdy support plate is held laterally beside the skin area where the split skin is to be cut. The skin is mobilized, pulled over the support plate, and fixed with the nondominant hand on the bottom of the device. Using a dermatome, the split skin graft is cut on the metal plate, which provides a flat surface to permit a precise harvesting process.
A total of 208 split skin grafts were harvested, of which nine had to be rejected. The average time to perform a split skin graft on one animal, not considering preparation time, was 2 minutes. All of the harvested grafts were 2 × 2.5 cm (0.79 × 0.98 inch), with a mean thickness of 0.3 mm. Reharvesting could be performed on postoperative day 7.
Using this new standardized method, grafts of equal size and thickness can be obtained rapidly. It is cheap and highly reproducible and can be carried out by a single surgeon. It provides a rapid healing process with fewer complications and immensely reduced stress for the animals.
No preview · Article · Apr 2011 · Plastic and Reconstructive Surgery