Mast cell concentration in the wound healing process of incisions made by different instruments

Tissue response to different incision tools in animal model

PURPOSE

The aim of this study is to compare the repair of incisions performed with microdissection electrocautery tip, conventional electrocautery tip, high potency diode laser, and conventional scalpel blade in a in vivo model.

METHODS

Different incisions were performed in adults Holtzman rats using the four types of instruments: microdissection electrocautery tip, conventional electrocautery tip, high potency diode laser, and conventional scalpel blade, in different periods of healing process. Thirty rats were divided into 5 groups, according to the period of euthanasia-24 h, 48 h, 72 h, 7 days, and 14 days. All animals received four incisions, each by a different method. Quantitative histological and histomorphometric analyses were performed using hematoxylin and eosin (HE) and Picrosirius Red staining.

RESULTS

Inflammatory profile and tissue repair presented small statistically significance differences comparing conventional scalpel blade and microdissection tip; moreover, both presented quantitatively superior to the others.

CONCLUSION

It is believed that the microdissection tip can perform a dynamic incision just as a common scalpel blade, but more effective. Furthermore, it can promote a better hemostatic control of the surgical field that is comparable to conventional electrocautery tip without affecting tissue repair.

Effect of snail mucus on angiogenesis during wound healing

Background: Angiogenesis is the process through which new blood vessels are formed from existing ones. This process plays an important role in supplying the oxygen and nutrients needed for cellular metabolism and eliminating cell debris during wound healing. Snail mucus can bind to several factors that stimulate angiogenesis, including vascular endothelial growth factor, platelet-derived growth factor, and fibroblast growth factor. The aim of this study is to observe changes in angiogenesis during the healing of wounds topically applied with snail mucus. Methods: Punch biopsy was performed on the back of male Wistar rats to obtain four wounds, and different concentrations of snail mucus were applied to each of these wounds. The animals were sacrificed on days 2, 4, and 7 to observe the extent of angiogenesis during wound healing by microscopy. Results: Two-way ANOVA showed differences in number of blood vessels formed (p = 0.00) and day of observation (p = 0.00) between groups. Post hoc Tukey's HSD test showed that 24% snail mucus treatment does not significantly affect wound healing (p = 0.488); by contrast, treatment with 48% and 96% snail mucus demonstrated significant effects on angiogenesis (p = 0.01). Spearman's test showed interactive effects between snail mucus concentration and day of observation on the extent of angiogenesis (p = 0.001, R = 0.946). Conclusion: Topical application of snail mucus gel can increase angiogenesis during wound healing in Wistar rat skin.

Healing of canine skin incisions made with monopolar electrosurgery versus scalpel blade

OBJECTIVE

To determine the influence of monopolar electrosurgery in cutting mode set at 10, 20, or 30 W on surgery time, hemostasis, and healing of cutaneous wounds compared to scalpel incisions.

STUDY DESIGN

Randomized blinded control trial.

ANIMALS

Dogs (n = 15).

METHODS

Four skin incisions were created on either side of the dorsal midline with a scalpel, or monopolar electrosurgery at 10, 20, and 30 W. Surgical time and incisional bleeding were measured. Each incision was assessed daily for edema, erythema and discharge, and complications. Healing was evaluated via histology at 7 days. Results were analyzed for significance at P ≤ .05.

RESULTS

Surgical time and hemostasis were improved in all electrosurgery groups. Erythema was reduced in all electrosurgical incisions for days 1-4, but was greater in wounds created via electrosurgery at 20 W than those made with a scalpel blade by day 7. No difference was noted in the degree of edema or presence of wound discharge. All histologic variables of tissue healing were lower in electrosurgical incisions than scalpel incisions (P < .001). Ten incisional complications occurred, all associated with electrosurgery.

CONCLUSIONS

The use of monopolar electrosurgery at 10, 20, and 30 W in a cutting waveform improved hemostasis and surgical time when incising canine skin, but delayed healing and increased complications within the first 7 days compared to scalpel incisions.

Craniosynostosis incision: scalpel or cautery?

There is an ongoing debate regarding the optimal instrument for scalp incisions: the scalpel or electrocautery. The argument generally focuses on improved healing after an incision made with a knife and decreased bleeding when using electrocautery. This study compares the use of scalpel and electrocautery in making coronal incisions for patients undergoing surgical correction of craniosynostosis. The outcome metric used is wound healing within 6 months after surgery. All patients presenting to the University of North Carolina Children's Hospital with craniosynostosis between July 1, 2007 and January 1, 2010 requiring a coronal incision for surgical correction were prospectively enrolled. In all of these patients, half of the coronal incision was made with knife; the other half, with needle tip cautery. Side of the incision was specified at the time of surgery in the operative report. Patients were excluded from the study if the instrument for incision was not specified or if only 1 modality was used for the entire incision. Sixty-eight patients underwent cranial vault reconstruction, of which 58 met inclusion criteria. Of the 58 matched pairs, 55 were analyzed statistically. The 3 excluded cases were those who had midline complications. There were 17 wound complications (15%): 8 in the knife group, 6 in the cautery group, and 3 at midline (with indeterminate side for the problem). We found no statistically significant difference in wound healing between incisions made with a knife or with electrocautery.

A statistical analysis of murine incisional and excisional acute wound models

Mice represent the most commonly used species for preclinical in vivo research. While incisional and excisional acute murine wound models are both frequently employed, there is little agreement on which model is optimum. Moreover, current lack of standardization of wounding procedure, analysis time point(s), method of assessment, and the use of individual wounds vs. individual animals as replicates makes it difficult to compare across studies. Here we have profiled secondary intention healing of incisional and excisional wounds within the same animal, assessing multiple parameters to determine the optimal methodology for future studies. We report that histology provides the least variable assessment of healing. Furthermore, histology alone (not planimetry) is able to detect accelerated healing in a castrated mouse model. Perhaps most importantly, we find virtually no correlation between wounds within the same animal, suggesting that use of wound (not animal) biological replicates is perfectly acceptable. Overall, these findings should guide and refine future studies, increasing the likelihood of detecting novel phenotypes while reducing the numbers of animals required for experimentation.

Mast Cells in Lung Homeostasis: Beyond Type I Hypersensitivity

Lungs are indispensable organs for the respiratory process, and maintaining their homeostasis is essential for human health and survival. However, during the lifetime of an individual, the lungs suffer countless insults that put at risk their delicate organization and function. Many cells of the immune system participate to maintain this equilibrium and to keep functional lungs. Among these cells, mast cells have recently attracted attention because of their ability to rapidly secrete many chemical and biological mediators that modulate different processes like inflammation, angiogenesis, cell proliferation, etc. In this review, we focus on recent advances in the understanding of the role that mast cells play in lung protection during infections, and of the relation of mast cell responses to type I hypersensitivity-associated pathologies. Furthermore, we discuss the potential role of mast cells during wound healing in the lung and its association with lung cancer, and how mast cells could be exploited as therapeutic targets in some diseases

Comparison of lateral thermal injury and healing of porcine skin incisions performed by CO2-laser, monopolar electrosurgery and radiosurgery: a preliminary study based on histological and immunohistochemical results

BACKGROUND

Despite the wide application of lasers and electrosurgery in dermatology, the pertinent literature provides conflicting data regarding the lateral thermal injury (LTI) associated with these instruments and its effects on wound healing. This study aims to quantitate the LTI produced by CO(2)-laser, monopolar electrosurgery (MES), and radiosurgery (MRS) and determine its effects on the healing process (re-epithelialization and inflammatory response) of incisional wounds.

METHODS

Five adult swine of similar weight (22.8-25 kg) were submitted to standardized full-thickness incisions on the lateral abdominal skin by the above instruments (at settings similar to those used in clinical practice) and scalpel (control group). Full-thickness specimens from the surgical site were harvested immediately afterwards and 48 hours later (days 1 and 3). The animals were euthanized by intravenous administration of propofol and pentobarbital. All specimens were formalin fixed, paraffin embedded, cut, and stained with hematoxylin-eosin to quantitate the extent of LTI and inflammatory infiltration. Sections of day 3 were stained with the MIB-1 monoclonal antibody to detect Ki-67 as a marker of epithelial cell proliferation adjacently to the incisions.

RESULTS

LTI was most extensive in the CO(2)-laser-group but did not differ significantly between MES- and MRS-groups. Immunohistochemistry ascertained significantly greater epithelial cell proliferation in the CO(2)-laser-group. Inflammatory infiltration was significantly greater in the CO(2)-laser-group, when compared with the controls but did not differ significantly between the MES/MRS and control groups.

CONCLUSION

CO(2) laser incisions exhibit more extensive LTI, epithelial cell proliferation, and inflammatory response. Confirmation of these findings requires a greater sample.

Mast Cells and Wound Healing

BACKGROUND

Mast cells (MC) are ubiquitous resident cells, traditionally viewed as effector cells of allergic reactions that can store and synthesize de novo many mediators upon activation by a variety of stimuli. Exciting new insights are unveiling MC involvement in the pathogenesis of connective tissue disorders including wound healing and fibrosis.

THE PROBLEM

Abnormal wound repair is associated with an increased number of MC strategically located around blood vessels. Therapeutic local manipulation of MC population and reactivity may help improve and even prevent impaired repair processes for which there is no cure.

BASIC/CLINICAL SCIENCE ADVANCES

Chymase, a MC-restricted protease, is pre-stored in MC cytoplasmic granules with other mediators. The development of a highly specific inhibitor targeting chymase established its pivotal effect on fibrosis pathogenesis in a mouse model of silica-induced fibrosis. This novel finding evokes the potential therapeutic relevance of chymase inhibition to prevent aberrant wound healing.

CLINICAL CARE RELEVANCE

MC are increased in number in a variety of fibrotic diseases, compared to normal scars. Chymase has become a rising target prompting the development of chymase-specific inhibitors to be used as prophylactic or therapeutic agents. Another emerging strategy may consist in evaluating the efficacy of mast cell stabilizing drugs such as cromolyn in abnormal wound healing-drugs which are already approved for human use in other MC-driven disorders.

CONCLUSION

Limited treatment success of dysregulated wound healing underscores the need for novel targets be considered such as MC and/or MC-derived mediators and the necessity to design new therapeutic strategies for wounds that remain difficult to treat.

Effect of propolis on mast cells in wound healing

Wound healing is divided into three phases: inflammatory, proliferative and remodeling. Mast cells participate in all these phases. The aim of the present study was to determine the effects of propolis on the population of mast cells in oral surgical wounds in comparison to the results obtained with dexamethasone. This study was prospective, in vivo, randomized, semiexperimental, quantitative and comparative animal. A circular surgical wound was made on the dorsum of the tongue of 90 hamsters divided into three experimental groups: topical application of 30% propolis alcoholic extract (Group 1); 0.1% dexamethasone in orabase cream (Group 2); and orabase cream alone (Group 3). Applications were performed every 12 h throughout the experiment. The postoperative times for killing of the animals were 1, 3, 7, 14 and 28 days. The Student's t test for independent samples was employed in the statistical analysis. In the inflammatory phase of healing, propolis caused a greater reduction in the number of mast cells on the edge and in the central region of the surgical wound in comparison to dexamethasone. Moreover, the number of mast cells on day 1 was lower in the central region of the wounds treated with the orabase cream alone in comparison to dexamethasone. In conclusion, the anti-inflammatory action of propolis mediated by mast cells was more effective than dexamethasone in the inflammatory phase of healing.