Simple interrupted percutaneous suture versus intradermal running suture for wound tensile strength measurement in rats: a technical note

The Lasso Suture: Ex Vivo Testing of an Alternative to the High-Tension Deep Dermal Stitch

SUMMARY

Wound dehiscence, with an estimated occurrence rate greater than 4% in plastic surgery, is generally underreported, and can be an indicator of increased mortality and remission rates. The authors developed the lasso suture as a stronger alternative to the current standard patterns. The lasso suture takes less time to perform than the standard high-tension wound repair method. The authors dissected caprine skin specimens to create full-thickness wounds for suture repair using simple interrupted, vertical mattress, horizontal mattress, and deep dermal with running intradermal (DDR) sutures ( n = 10) and lasso sutures ( n = 9). They then conducted uniaxial failure testing to quantify the suture rupture stresses and strains. They also measured the suture operating time with medical students and residents (PGY or MS programs) performing wound repair (10-cm wide, 2-cm deep, 2-0 polydioxanone sutures) on soft-fixed human cadaver skin. The lasso stitch had a greater first-suture rupture stress compared with all other patterns ( P < 0.001): 2.46 ± 0.27 MPa for lasso versus 0.69 ± 0.14 MPa for simple interrupted, 0.68 ± 0.13 MPa for vertical mattress, 0.50 ± 0.10 MPa for horizontal mattress, and 1.17 ± 0.28 MPa for DDR sutures. Performing the lasso suture was 28% faster than performing standard DDR (264 ± 21 versus 349 ± 25 seconds; P = 0.027). In summary, the authors showed that the lasso has superior mechanical properties compared with the studied traditional sutures, and that the new technique can be performed more quickly than the current standard (DDR stitch) for high-tension wounds. Future animal and in-clinic studies will be helpful to confirm the authors' findings in this proof-of-concept study.

CLINICAL RELEVANCE STATEMENT

The authors propose the lasso suture, a new suturing method with improved tensile performance compared with traditional techniques and a faster operative time than the deep dermal stitch typically used for high-tension wounds in reconstructive surgery to prevent wound dehiscence.

Theaflavin Attenuates TBHP-Induced Endothelial Cells Oxidative Stress by Activating PI3K/AKT/Nrf2 and Accelerates Wound Healing in Rats

The treatment of wounds remains a clinical challenge because of poor angiogenesis under the wound bed, and increasingly, the patients’ need for functional and aesthetically pleasing scars. Previous reports have shown that Theaflavin can induce angiogenesis and terminate the progression of ischemic cardiovascular disease, but limited therapy is available for the management of cutaneous wounds. In this study, our in vitro work discovered that human umbilical vein endothelial cells (HUVECs) exposed to Theaflavin can alleviate apoptosis and cell dysfunction induced by tert-butyl hydroperoxide (TBHP). The cellular activity of HUVECs were assessed by cell tube formation, migration and adhesion. Mechanistically, Theaflavin protected HUVECs from TBHP-stimulated cell apoptosis through the activation of the phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT)/nuclear factor (erythroid-derived 2)-like 2 (Nrf2) axis, so Nrf2 silencing can partly eliminate the cytoprotective effect of Theaflavin treatment. In in vivo experiments, administering Theaflavin orally can enhance vascularization in regenerated tissues and accelerate wound healing. In summary, our data served as a novel evidence for the wound healing treatment with Theaflavin, and certified the potential mechanism of Theaflavin, which can be used as a potential agent for cutaneous wound therapy.

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.

Human galectin‑3: Molecular switch of gene expression in dermal fibroblasts in vitro and of skin collagen organization in open wounds and tensile strength in incisions in vivo

Understanding the molecular and cellular processes in skin wound healing can pave the way for devising innovative concepts by turning the identified natural effectors into therapeutic tools. Based on the concept of broad-scale engagement of members of the family of galactoside-binding lectins (galectins) in pathophysiological processes, such as cancer or tissue repair/regeneration, the present study investigated the potential of galectins-1 (Gal-1) and −3 (Gal-3) in wound healing. Human dermal fibroblasts, which are key cells involved in skin wound healing, responded to galectin exposure (Gal-1 at 300 or Gal-3 at 600 ng/ml) with selective changes in gene expression among a panel of 84 wound-healing-related genes, as well as remodeling of the extracellular matrix. In the case of Gal-3, positive expression of Ki67 and cell number increased when using a decellularized matrix produced by Gal-3-treated fibroblasts as substrate for culture of interfollicular keratinocytes. In vivo wounds were topically treated with 20 μg/ml Gal-1 or −3, and collagen score was found to be elevated in excisional wound repair in rats treated with Gal-3. The tensile strength measured in incisions was significantly increased from 79.5±17.5 g/mm² in controls to 103.1±21.4 g/mm² after 21 days of healing. These data warrant further testing mixtures of galectins and other types of compounds, for example a combination of galectins and TGF-β1.

TGF-β expression and wound tensile strength after simple interrupted suturing and zip surgical skin closure (IN VIVO study)

Primary healing occurs when both edges of the adjacent incision wound meet. To achieve primary healing, bringing the wound edges closer is generally done by suturing. At present comes one of the methods of skin incision closure without involving sutures called zip surgical skin closure. As an indicator of commonly used wound healing, tensile strength is produced by collagen that involves TGF-β in its production. This study was aimed to observe the expression of TGF-β and tensile strength of the skin incision-post wound using simple interrupted suturing or zip surgical skin closure. An experimental laboratory, this study used Sprague Dawley rats with the predetermined inclusion criteria. Thirty-six rats were applied with 3 cm-dorsal skin incisions after which they were divided into 2 groups, group 1 received simple interrupted suturing and group 2 received zip surgical skin closure. TGF-β examination was performed with BS-0086R polyclonal antibodies and wound tensile strength was observed on day 3, 7 and 14. The independent t-test showed that the tensile strength of the zip surgical skin closure group was higher and was significant as observed on day 7 (p = 0.000) than that of the simple interrupted suturing group. TGF-β expression in the zip surgical skin closure group was found more numerous and significant on day 7 and 14 than that of in the simple interrupted group, (p = 0.025) and (p = 0.032) respectively. Conclusion. Skin incision-post wound healing with zip surgical skin closure is better and shows higher tensile strength and more numerous TGF-β expressions than simple interrupted suturing.

Wound healing after excision of subcutaneous tumors treated with near-infrared photoimmunotherapy

Near‐infrared photoimmunotherapy (NIR‐PIT) is a novel cancer therapy that employs a combination of infrared light and tumor‐targeted monoclonal antibody‐photoabsorber conjugates to cause both direct tumor necrosis and immunogenic cell death. NIR‐PIT may have potential in the perioperative setting before surgery, and therefore it is important to know the effect of NIR‐PIT on wound healing. Fifty mice were implanted with subcutaneous xenografts of N87 human gastric cancer cells, and tumors were excised after reaching a predetermined size. After excision, 30 mice were split into three groups: Controls, NIR‐PIT 1 day prior to surgery and NIR‐PIT 3 days prior to surgery. The quantity of reactive oxygen species (ROS) in each wound was measured on Postoperative Days 2 and 4, and mice were monitored weekly for 4 weeks for evidence of local tumor recurrence as well as clinical evidence of wound healing complications (eg, dehiscence, infection). The remaining 20 mice (10 controls, 10 treated with NIR‐PIT 1 day prior to surgery) were sacrificed on either Postoperative Day 7 or 14, the skin around wounds were excised, and tensile strength was measured with a digital force gauge. There were no significant differences between treatment and control groups with respect to wound ROS levels, wound tensile strength, local tumor recurrence, or postoperative complication rates (P > .05). In conclusion, neoadjuvant (pre‐operative) NIR‐PIT shows no evidence of adverse wound healing effects, and it is likely a safe adjunctive treatment to surgery. Postoperative use of NIR‐PIT merits investigation.

Aesculus hippocastanum L. Extract Does Not Induce Fibroblast to Myofibroblast Conversion but Increases Extracellular Matrix Production In Vitro Leading to Increased Wound Tensile Strength in Rats

The ability of horse chestnut extract (HCE) to induce contraction force in fibroblasts, a process with remarkable significance in skin repair, motivated us to evaluate its wound healing potential in a series of experiments. In the in vitro study of the ability of human dermal fibroblasts to form myofibroblast-like cells was evaluated at the protein level (Western blot and immunofluorescence). The in vivo study was conducted on male Sprague-Dawley rats with inflicted wounds (one open circular and one sutured incision) on their backs. Rats were topically treated with two tested HCE concentrations (0.1% and 1%) or sterile water. The control group remained untreated. The incisions were processed for wound tensile strength (TS) measurement whereas the open wounds were subjected to histological examination. On the in vitro level the HCE extract induced fibronectin-rich extracellular matrix formation, but did not induced α-smooth muscle actin (SMA) expression in dermal fibroblasts. The animal study revealed that HCE increased wound TS and improved collagen organization. In conclusion, the direct comparison of both basic wound models demonstrated that the healing was significantly increased following HCE, thus this extract may be found useful to improve healing of acute wounds. Nevertheless, the use of an experimental rat model warrants a direct extrapolation to the human clinical situation.

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.

Plantago lanceolata L. water extract induces transition of fibroblasts into myofibroblasts and increases tensile strength of healing skin wounds

OBJECTIVES

Although the exact underlying mechanisms are still unknown, Plantago lanceolata L. (PL) water extracts are frequently used to stimulate wound healing and to drain abscesses. Therefore, in this experimental study the effect of PL water extract on skin wound healing was studied in Sprague-Dawley rats.

METHODS

Two excisional and one incisional skin wounds were performed on the back of each rat. Wounds were treated for three consecutive days with two different concentrations of the aqueous extract of PL. Rats were sacrificed 7, 14, and 21 days after surgery. Samples of wounds were processed for macroscopic (excisions - wound contraction measurement), biomechanical (incisions - wound tensile strength (TS) measurement) and histological examination (excisions).

KEY FINDINGS

It was shown that open wounds treated with PL extract contained myofibroblasts and demonstrated significantly higher contraction rates. Furthermore, significantly increased wound TSs were recorded in treated rats as a consequence of increased organization of extracellular matrix proteins, such as the collagen type 1.

CONCLUSIONS

We demonstrated that PL aqueous extract improves skin wound healing in rats. However, further research need to be performed to find optimal therapeutic concentration, and exact underlying mechanism prior obtained results may be introduced into the clinical practice.

Low-level laser therapy with 810 nm wavelength improves skin wound healing in rats with streptozotocin-induced diabetes

OBJECTIVE

The aim of present study was to evaluate whether low-level laser therapy (LLLT) can reverse the impaired wound healing process in diabetic rats.

BACKGROUND DATA

Impaired wound healing in diabetic patients represents a major health problem. Recent studies have indicated that LLLT may improve wound healing in diabetic rats, but the optimal treatment parameters are still unknown.

MATERIALS AND METHODS

Male Sprague-Dawley rats (n=21) were randomly divided into three groups: a healthy control group, a diabetic sham-treated group, and a diabetic LLLT-treated group. Diabetes mellitus was then induced by streptozotocin administration to the two diabetic groups. One 4 cm long full thickness skin incision and one full thickness circular excision (diameter=4 mm) were performed on the back of each rat. An infrared 810 nm laser with an output of 30 mW, a power density of 30 mW/cm(2), and a spot size of 1 cm(2) was used to irradiate each wound for 30 sec (daily dose of 0.9 J/cm(2)/wound/day).

RESULTS

In diabetic rats, the histology of LLLT-treated excisions revealed a similar healing response to that in nondiabetic controls, with significantly more mature granulation tissue than in the sham-treated diabetic control group. LLLT reduced the loss of tensile strength, and increased the incision wound stiffness significantly compared with sham-irradiated rats, but this did not achieve the same level as in the nondiabetic controls.

CONCLUSIONS

Our study demonstrates that infrared LLLT can improve wound healing in diabetic rats. Nevertheless, further research needs to be performed to evaluate the exact underlying mechanism and to further optimize LLLT parameters for clinical use.

Skin wound healing in obese and lean male adolescent rats submitted to pre-weaning litter size manipulation

We investigated whether early postnatal over-nutrition affects normal course of skin wound healing. To induce over-nutrition the litter size was adjusted on the first day after birth to four pups/nest (small litters). In parallel, as a control, normal nests of 10 pups/nest (normal litters) were used. For the wound healing experiment 30 male Sprague-Dawley rats, 15 from normal nests and 15 from small nests, were used. Two parallel full-thickness skin incisions and two full-thickness excisions were performed on the back of each rat. Samples for histological examination (excisions) and wound tensile strength measurement (incisions) were collected on days 2, 6, and 14 after surgery. Our study demonstrates that rats from the small nests had enhanced plasma levels of insulin and enhanced body weight/fat parameters. Furthermore, in small nests, rats that expressed the above-mentioned symptoms displayed slight improvement of epidermis regeneration, accelerated demarcation line formation, and increased wound tensile strength. From this point of view the small nest model used in the present experiment is helpful for exploration whether these acquired changes might be considered as a sufficient essential factor involved in the regulation of metabolic homeostasis and wound repair in juvenile obese male rats. Nevertheless, further studies need to be performed to verify the present findings also on other animal models and humans and to describe the exact underlying mechanism.