Viability Of Skin Flaps In Rats Research Articles

The Effect of Adipose Derived Stromal Vascular Fraction on Flap Viability in Experimental Diabetes Mellitus and Chronic Renal Disease

Background The presence of chronic renal disease(CRD) concurrently with diabetes mellitus(DM) increases the flap failure. Adipose derived stromal vascular fraction (SVF) is known to enhance skin flap viability in both healthy and diabetic individuals. The aim of this experimental study was to investigate the effect of SVF on skin flap viability in rats with DM and CRD. Methods 48 Sprague-Dawley rats were separated into four groups as follows: group I (control), group II (diabetes mellitus), group III (chronic renal disease), and group IV (diabetes with chronic renal disease).Two dorsal flaps were elevated. Flaps on left side of all groups received 0.5 cc of SVF, while same amount of plasma-buffered saline (PBS) was injected into right side. On postoperative day 7, flaps were harvested for macroscopic, histopathologic and biochemical assessments. Areas of flap survival were measured macroscopically. Blood level of vascular endothelial growth factor (VEGF) was measured after injection of SVF. Results Macroscopically, SVF has significantly improved flap viability (p < 0.05). Flap viability percentage was lower in DM and CRD groups when compared with healthy control group. In respect of new capillary formation, there was a statistically significant difference between SVF injected flaps and PBS injected sides (p < 0.05). Similarly, VEGF levels were higher in all study groups and there was a significant difference in comparison to control group (p < 0.05). Conclusions The study showed that injection of SVF increased flap viability via endothelial differentiation and neovascularization. In vivo function of stem cells might be impaired due to uremia and diabetes-related microenviromental changes.

Sub-Flap Use of Nano-Selenium Oxide Solution Enhances Skin Flap Viability in Rats: Study the Novel Role of mTOR and p-mTOR Expression.

Nano-selenium oxide (NSeO) particles are highly noticeable due to their tissue-protective and antioxidant properties. For this purpose, the effect of NSeO was evaluated on skin flap survival and flap oxidative stress markersin rats. Also, another effect of NSeO was investigated on the expression of mTOR and p-mTOR. Fifty rats were divided into five groups of ten. Skin flap size was 3×8 cm in all groups. Groups were: (1) Sham, (2) Flap Surgery group, (3) Flap Surgery + NSeO, (4) Flap Surgery + Rapamycin (mTOR inhibitor), (5) Flap Surgery + Rapamycin + NSeO. The flap necrosis rate was computed using the paper pattern method on day seven after surgery. After day seven, flap tissues were collected for histological evaluations. Then, malondialdehyde (MDA) content and superoxide dismutase (SOD) activity were measured. Furthermore, the expression levels of mTOR and p-mTOR were measured using the Western blot method. Treatment with NSeO significantly reduced necrosis (P&lt;0.05). It also resulted in a decrease in MDA level (P&lt;0.05). Histologically, NSeO reduced inflammation and increased positive signs of tissue healing (epithelialization, neovascularization, fibroblast migration, and granulation tissue). NSeO increased SOD activity significantly (P&lt;0.05), whereas, using rapamycin reversed these effects. Also, in all groups, mTOR changes were not significant. Additionally, p-mTOR expression was significantly reduced in groups that rapamycin was injected. NSeO can reduce flap necrosis and enhance tissue healingin rats. So, it can potentially be used clinically to promote tissue repair significantly, and its effects are independent of the mTOR pathway. This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Photobiomodulation effect in tumoral necrosis factor-alpha(TNF-α) on the viability of random skin flap in rats.

The aim of this study was to investigate the effect of red laser (660 nm) photobiomodulation (PBM) with different energies on tumor necrosis factor-alpha(TNF-α) expression for random skin flap viability in rats. Twenty-four Wistar rats were divided into three groups: sham group (SG), PBM laser group with an energy dose of 0.29 J (0.29G), and PBM laser group with an energy dose of 7.30 J (7.30G). A cranially based dorsal skin flap measuring 10 × 4 cm was raised and a plastic barrier was placed between the flap and its bed. PBM was applied in 3 timepoints: in the immediate postoperative period, in the 1st and in the 2nd postoperative days; the animals were euthanized on the 7th postoperative day. The assessments included: TNF-α expression of 3 different flap areas (proximal, medial and distal), by immunohistochemistry; percentage of skin flap necrosis area, by the paper template method. The statistical analysis was performed through the Kruskal-Wallis and Mann-Whitney tests, the level of significance adopted was 5% (p < 0.05). TNF-α expression was significantly lower for 7.30G in the proximal area, reduced for SG in the medial point, and larger for 7.30G in the distal area. The percentage of flap necrosis area was significantly reduced for 7.30G. Higher energy doses are more efficacious than lower energy doses for modulating TNF-α expression. PBM with an energy dose of 7.30 J was effective in reducing the expression of TNF-α and increase skin flap viability.

Effect of dipyridamole on random pattern skin flap viability in rats

Ischemic necrosis has been most dreaded complication of flap reconstruction. Therefore, researchers have tried to improvise modalities to prevent or treat it since the onset of flap surgery. So far these researches have failed to identify a pharmacological therapy equally effective as surgical delay in augmenting skin flap viability. In the path of search for this substance, dipyridamole attracted our attention as an antiaggregant agent. Put together with pathophysiological mechanisms underlying ischemic flap necrosis, we concluded dipyridamole might have beneficial effect on survival of skin flaps. In this research random pattern dorsal rat skin flap model of McFarlane is used. Subjects are separated in a randomized fashion between two groups. Experiment group is given dipyridamole with a dose of 20 mg/kg twice daily. Control group is given same amount of saline. At seventh day viability of skin flaps is assessed and compared between groups. Also on 7th day, pathologic specimens are obtained and evaluated histopathologically in terms of neutrophil and lymphocyte infiltration, edema and fibrosis. Necrosis percentage in experiment group is found to be significantly lower than that of control group (p < 0.01*). Neutrophil infiltration and edema found to be significantly lower in dipyridamole group (p < 0.05*). No significant difference is observed in lymphocyte infiltration and fibrosis. Dipyridamole is shown in this research to be effective in augmenting viability of random pattern skin flaps in rats. Nevertheless, more extensive researches are needed to fully determine its precise mechanism, side effects and appropriate doses.

Amlodipine improves skin flap viability in rats exposed to nicotine

Background: A recent series of experimental and clinical studies have demonstrated the negative effects of nicotine such as ischemia and necrosis of skin flaps. In order to overcome the negative effects of nicotine numerous studies have been conducted with various agents and methods. In this study, we investigated the effects of amlodipine (AML) on flap survival in nicotinized rats. Materials and Methods: Thirty Sprague Dawley rats were randomly divided into three groups: Group A nicotine; Group B nicotine + AML; Group C control group. The rats in Group A and B have received nicotine for 4 weeks before the surgical intervention. At the end of the 4th week, MacFarlane flaps were elevated and adapted back by suturing in all groups. In Group B, AML has been administered to the rats after the surgery and continued for 10 days. All the flaps were visualized with fluorescein angiography and underwent histopathological assessment. The necrotic areas of the flaps were measured as well. Results: The necrosis rate in Group A was found to be significantly higher compared to Group B (P

Genistein Improves Skin Flap Viability in Rats: A Preliminary In Vivo and In Vitro Investigation.

Selective estrogen receptor modulators (SERMs) have been developed to achieve beneficial effects of estrogens while minimizing their side effects. In this context, we decided to evaluate the protective effect of genistein, a natural SERM, on skin flap viability in rats and in a series of in vitro experiments on endothelial cells (migration, proliferation, antioxidant properties, and gene expression profiling following genistein treatment). Our results showed that administration of genistein increased skin flap viability, but importantly, the difference is only significant when treatment is started 3 days prior the flap surgery. Based on our in vitro experiments, it may be hypothesized that the underlying mechanism may rather by mediated by increasing SOD activity and Bcl-2 expression. The gene expression profiling further revealed 9 up-regulated genes (angiogenesis/inflammation promoting: CTGF, CXCL5, IL-6, ITGB3, MMP-14, and VEGF-A; angiogenesis inhibiting: COL18A1, TIMP-2, and TIMP-3). In conclusion, we observed a protective effect of genistein on skin flap viability which could be potentially applied in plastic surgery to women undergoing a reconstructive and/or plastic intervention. Nevertheless, further research is needed to explain the exact underlying mechanism and to find the optimal treatment protocol.

Abstract: Does Non-Smoked Nicotine Intake Increase Risk of Post-Operative Complications?

INTRODUCTION: The detrimental health effects of smoking tobacco are well known. Smoking tobacco increases the risks of many post-operative complications, many of which are germane to plastic surgery. The use of non-tobacco nicotine sources has proliferated in the hope that non-smoking delivery methods are safer than smoking; however, there is little data to support or refute this theory.1–4 METHODS: 5 year prospective study, (1/1//2012-12/2016). We informed patients that they should not smoke for 4 weeks before and 6 weeks after their surgery date. Each patient consented to study and allowed their urine to be tested the day of surgery. The patients were encouraged to stop all nicotine use, but if necessary, non-smoked delivery systems (ie transcutaneous patch, chewing gum) would be tolerated. The urine cotinine level was measured in patients undergoing major flap surgery or having general anesthesia. Patients were followed for 6 weeks to monitor for post-operative complications. Post-operative complications included any unplanned outcome requiring medical attention including but not restricted to infections, wound healing problems, unanticipated return to the operating room, etc. We then divided the patients into four groups: non-nicotine users (in the past year), smokers with negative urine test, smokers with positive urine test and non-smoked nicotine users. RESULTS: A total of 340 patients were tested. As expected non-nicotine users (n=264), had the lowest rate of complications at 18% (48). Tobacco smokers that tested positive (21) had the highest complication rate at 28.6% (6), while those testing negative (41) had rate of 19.5% (8) similar to non-smokers. Of note, patients using non-smoked nicotine source (14), developed the highest rate of complications 42.9% (6). Analysis of variance test, p-value of 0.26. CONCLUSION: There is evidence that even when administered through non-smoked methods nicotine does increase the risk of post-operative complications. The increased complication rate in non-smoked nicotine users may be related to higher nicotine blood levels, as it is possible that patches, chewing gum and vaporized usage encourages greater consumption. Given the increasing usage of non-smoked nicotine sources and the perception that the product offers a safe alternative to traditional tobacco use, further studies should be undertaken to better understand clinical implications of usage in aesthetic and plastic surgery. A larger study size could allow for data to reach statistically significant level. Reference Citations: 1. PDE-5 inhibition improves skin flap viability in rats that are exposed to nicotine. Shah A, Pfaff MJ, Assi R, Wu W, Steinbacher DM. Microsurgery. 2014 Jul;34(5):390–7. 2. The effect of hyperbaric oxygen therapy on the survival of random pattern skin flaps in nicotine-treated rats. Selçuk CT, Kuvat SV, Bozkurt M, Yaşar Z, Gülsün N, Ilgezdi S, Ula M, Ozalp B. J Plast Reconstr Aesthet Surg. 2012 Apr;65(4):489–93. 3. Impact of nicotine replacement therapy on postoperative mortality following coronary artery bypass graft surgery. Paciullo CA, Short MR, Steinke DT, Jennings HR. Ann Pharmacother. 2009 Jul;43(7):1197–202. 4. The association of nicotine replacement therapy with mortality in a medical intensive care unit. Lee AH, Afessa B. Crit Care Med. 2007 Jun;35(6):1517–21

The effects of epinephrine and dobutamine on skin flap viability in rats: A randomized double-blind placebo-controlled study

Intraoperative reduction in arterial pressure may cause hypoperfusion of skin flaps, which may increase the risk of flap failure. There is no international consensus regarding the use of vasoactive or inotropic agents to restore or maintain flap perfusion. The purpose of this study was to evaluate the effects of the intraoperative administration of epinephrine and dobutamine on axial-pattern skin flap survival in rats. Fifty-four Sprague Dawley rats were randomized into three groups (n=18). A tubed axial-pattern skin flap was performed. Animals were randomized to receive an intraperitoneal injection of epinephrine 0.1mg/kg, dobutamine 0.3mg/kg, or saline (0.5ml). The rats were euthanized after 7 days and the viable area of the flap was compared between the groups using a digital imaging and computer software. Seven rats/flaps were excluded from the study due to autocannibalism (n=3), postoperative tracheal obstruction (n=2), anesthesia-induced respiratory arrest (n=1), and abnormal behavior requiring euthanization (n=1). The mean flap survival was 46%±9% in the saline group (n=17), 41%±9% in the epinephrine group (n=14) (p=0.088 compared to the saline group), and 54%±9% in the dobutamine group (n=16) (p=0.02 compared to the saline group and p=0.001 compared to the epinephrine group). Intraoperative intraperitoneal injection of dobutamine improves skin flap survival in rats, whereas intraperitoneal epinephrine tends to decrease skin flap survival.

PDE-5 inhibition improves skin flap viability in rats that are exposed to nicotine

Nicotine causes ischemia and necrosis of skin flaps. Phosphodiesterase-5 (PDE-5) inhibition enhances blood flow and vasculogenesis. This study examines skin flap survival in rats exposed to nicotine that are treated with and without PDE-5 inhibition. Eighty six rats were divided into five groups. Group 1 received saline subcutaneous (SC) once per day. Group 2 received nicotine SC 2 mg/kg day. Group 3 received sildenafil intraperitoneal (IP) 10 mg/kg day. Group 4 received nicotine SC 2 mg/kg and sildenafil IP 10 mg/kg day. Group 5 received nicotine SC 2 mg/kg day and sildenafil IP 10 mg/kg two times daily. After 28 days of treatment, modified McFarlane flaps were created, silicone sheets were interposed, and flaps were sutured. Photographs were taken on postoperative days 1, 3, and 7 and fluorescence angiography was used on day 7, both to evaluate for skin flap necrosis. Rats were euthanized and flaps were harvested for Vascular Endothelial Growth Factor (VEGF) Western blot analysis. Images were analyzed by three blinded observers using ImageJ, and necrotic indices were calculated. The nicotine and PDE-5 inhibition twice-daily group showed a 46% reduction in flap necrosis when compared to saline only (P < 0.05) and a 54% reduction when compared to nicotine only (P < 0.01). Fluorescence angiographic image analysis revealed reductions in flap necrosis (P < 0.01). VEGF analysis trended toward increased VEGF for all sildenafil-treated groups (P > 0.05). PDE-5 inhibition exhibits a dose-dependent reduction in skin flap necrosis in rats exposed to nicotine. This suggests that PDE-5 inhibition may mitigate the ill effects of smoking on skin flaps.

Ratlarda Deri Fleplerinin Yaşayabilirliğini Artırmada N-Asetil Sisteinin Etkisi

Amaç: Flep nekrozu yetersiz kan dolaşımı ve iskemi-reperfüzyon hasarının bir sonucu olarak gelişir. Serbest oksijen radikalleri deri doku hasarı oluşumuna katılarak kısmi flep nekrozuna neden olurlar. Bu nedenle çalışmada antioksidan olan N-asetil sistein (NAC)'in, sıçanlarda deri fleplerinin yaşayabilirliği üzerine etkisinin araştırılması amaçlanmıştır. Gereç ve Yöntemler: Çalışmadaki deneylerin tümü Fırat Üniversitesi Hayvan Deneyleri Yerel Etik Kurulu'ndan izin alınarak yapıldı. Çalışmada 14 erkek Wistar sıçanı kullanıldı. Bunlar rastgele olarak kontrol grubu ve NAC-grubu olmak üzere yedişerli iki gruba ayrıldı. Her iki gruptaki tüm sıçanlarda dorsal bölgeden 2x7 cm boyutlarında deri flebi kaldırıldı. NAC-grubunun sıçanlarına kas içi olarak günlük sabah akşam 20 mg/kg dozda (günlük total doz: 40 mg/kg), 10 gün süre ile NAC uygulandı. Kontrol grubu sıçanlarına ise 10 gün süre ile aynı zamanlarda diğer gruba verilen NAC solüsyonu hacminde (0,15 mL) %0,9 NaCl solüsyonu kas içi olarak verildi. Operasyon sonrası 10. günde deri flebi canlılığı değerlendirildi. Canlı deri flebi alanının büyüklüğü kontrol grubu ile NAC grubu arasında kıyaslandı. Bulgular: Kas içi NAC enjeksiyonu deri flebinin yaşayabilirliğinde kontrol grubuna göre istatistiksel olarak anlamlı düzeyde artışla sonuçlandı [NAC grubunda deri flep yaşayabilirliği, %59,89 (31,28-66,64); %35,70 (17,25-44,07); p=0,026]. Sonuç: Bu çalışmadan elde edilen bulgulara göre, NAC uygulaması deri fleplerinin yaşayabilirliğini önemli derecede arttırmıştır. Bu nedenle NAC uygulamasının flep cerrahisi tedavisini desteklemek için kullanılabileceği düşünülmektedir.

Effects of 830 and 670 nm Laser on Viability of Random Skin Flap in Rats

This study aimed to investigate the effect of 830 and 670 nm diode laser on the viability of random skin flaps in rats. Low-level laser therapy (LLLT) has been reported to be successful in stimulating the formation of new blood vessels and reducing the inflammatory process after injury. However, the efficiency of such treatment remains uncertain, and there is also some controversy regarding the efficacy of different wavelengths currently on the market. Thirty Wistar rats were used and divided into three groups, with 10 rats in each. A random skin flap was raised on the dorsum of each animal. Group 1 was the control group, group 2 received 830 nm laser radiations, and group 3 was submitted to 670 nm laser radiation (power density=0.5 mW/cm(2)). The animals underwent laser therapy with 36 J/cm(2) energy density (total energy=2.52 J and 72 sec per session) immediately after surgery and on the 4 subsequent days. The application site of laser radiation was one point at 2.5 cm from the flap's cranial base. The percentage of skin flap necrosis area was calculated on the 7th postoperative day using the paper template method. A skin sample was collected immediately after to determine the vascular endothelial growth factor (VEGF) expression and the epidermal cell proliferation index (KiD67). Statistically significant differences were found among the percentages of necrosis, with higher values observed in group 1 compared with groups 2 and 3. No statistically significant differences were found among these groups using the paper template method. Group 3 presented the highest mean number of blood vessels expressing VEGF and of cells in the proliferative phase when compared with groups 1 and 2. LLLT was effective in increasing random skin flap viability in rats. The 670 nm laser presented more satisfactory results than the 830 nm laser.

Effect of Low-Level Laser Therapy on Malondialdehyde Concentration in Random Cutaneous Flap Viability

The aim of this study was to assess the effects of 830 and 670 nm laser on malondialdehyde (MDA) concentration in random skin-flap survival. Low-level laser therapy (LLLT) has been reported to be successful in stimulating the formation of new blood vessels and activating superoxide-dismutase delivery, thus helping the inhibition of free-radical action and consequently reducing necrosis. Thirty Wistar rats were used and divided into three groups, with 10 rats in each one. A random skin flap was raised on the dorsum of each animal. Group 1 was the control group; group 2 received 830 nm laser radiation; and group 3 was submitted to 670 nm laser radiation. The animals underwent laser therapy with 36 J/cm(2) energy density immediately after surgery and on the 4 days subsequent to surgery. The application site of the laser radiation was 1 point, 2.5 cm from the flap's cranial base. The percentage of the skin-flap necrosis area was calculated 7 days postoperative using the paper-template method, and a skin sample was collected immediately after as a way of determining the MDA concentration. Statistically significant differences were found between the necrosis percentages, with higher values seen in group 1 compared with groups 2 and 3. Groups 2 and 3 did not present statistically significant differences (p > 0.05). Group 3 had a lower concentration of MDA values compared to the control group (p < 0.05). LLLT was effective in increasing the random skin-flap viability in rats, and the 670 nm laser was efficient in reducing the MDA concentration.

Effect of Application Site of Low-Level Laser Therapy in Random Cutaneous Flap Viability in Rats

This study aimed to investigate the effect of diode laser (830 nm) irradiation on the viability of ischemic random skin flaps in rats, as well as to determine the most effective site for applying laser radiation to speed healing. Low-level laser therapy (LLLT) has recently been used to improve the viability of ischemic random skin flaps in rats. Seventy Wistar rats were used and divided into seven groups of 10 rats each: group 1, sham laser treatment; group 2, which received irradiation at 1 point 5 cm from the flap's cranial base; group 3, which received irradiation at 2 points (5 and 7.5 cm from the flap's base); group 4, which received irradiation at 3 points (2.5, 5 and 7.5 cm from the flap's base); group 5, which received irradiation at 1 point 2.5 cm from the flap's base; group 6, which received irradiation at 2 points (2.5 and 5 cm from the flap's base); and group 7, which received irradiation at 1 point 7.5 cm from the flap's base. The animals were subjected to laser therapy at an energy density of 36 J/cm(2) for 72 sec immediately after surgery, and one time on each of the four subsequent days. The percentage of necrotic skin flap area was calculated on the seventh postoperative day using a paper template. The results showed that the rats in group 5 had the highest increase in skin flap viability, with a statistically significant difference compared to the other groups. Statistically significant differences were not seen between any of the other groups. The diode laser was effective in increasing skin flap viability in rats, and laser irradiation of a point 2.5 cm from the cranial base flap was found to be the most effective.

Histamine iontophoresis on the viability of random skin flap in rats

To evaluate the effects of the histamine iontophoresis on the random skin flap viability in rats. Sixty adult male Wistar rats were used. A cranially-based dorsal skin flap measuring 10 x 4 cm was raised and a plastic barrier was placed between the flap and its bed. After the surgical procedure, the animals were randomized into four groups (G1-G4) (n=15 each group) as follows: G1 (control)--sham electrical stimulation, G2 (electrical stimulation)--direct current electrical stimulation, G3 (histamine)--histamine and sham electrical stimulation, and G4 (histamine iontophoresis)--transdermal iontophoresis of histamine. In all groups the procedures were performed immediately after the surgery and on the two subsequent days. The percentage of flap necrosis was measured on the seventh postoperative day. The mean and the respective standard deviation of the percentage of flap necrosis areas were as follows: G1 (control) - 47.87 +/- 9.13%, G2 - 51.49 +/- 8.19%, G3 - 46.33 +/- 8.32% and G4 - 30.82 +/- 11.25%. The G4 group presented a significantly smaller amount of flap necrosis when compared to the other groups (p<0.001). The topical administration of the histamine by iontophoresis was effective to increase the viability of the random skin flaps in rats.

Depletion of Glutathione by Buthionine Sulfoximine Decreases Random-Pattern Skin Flap Viability in Rats

Glutathione (GSH) is one of the most highly concentrated intracellular antioxidants. Exogenous GSH has been shown to increase random-pattern skin flap survival. However, the effects of endogenous GSH depletion on random-pattern skin flap viability have never been studied. To evaluate the effects of systemic glutathione depletion on random-pattern skin flap survival in rats, 28 Wistar albino rats were divided into control, sham, and BSO (buthionine sulfoximide, a selective inhibitor for gamma-glutamylcysteine synthetase) groups. Dorsal, cranial-based random-pattern skin-flaps were elevated and the percentage of flap necrosis was measured in all rats at the postoperative day 7. BSO-treated rats showed increased skin flap necrosis when compared with untreated animals (P < 0.001). High-dose BSO treatment group had more clinically evident necrosis than low dose group (P < 0.05). This study reveals the importance of endogenous GSH for random skin-flap viability.

Helium-neon laser in viability of random skin flap in rats

The purpose of this study was to determine the role of helium-neon (He-Ne) laser random skin flap viability in rats. Experimentally controlled randomized study. Forty-eight Wistar-EPM rats were used, weighed, and divided into 4 groups with 12 rats each. The random skin flap was performed measuring 10 x 4 cm, with a plastic sheet interposed between the flap and the donor site. The Group 1 (control) underwent sham irradiation with He-Ne laser. The Group 2 was submitted to laser irradiation, using the punctual contact technique on the skin flap surface. The Group 3 was submitted to laser irradiation surrounding the skin flap, and the Group 4 was submitted to laser irradiation both on the skin flap surface and around it. The experimental groups were submitted to He-Ne laser irradiation with 3 J/cm(2) energy density immediately after the surgery and for the four subsequent days. The percentage of necrotic area of the four groups was calculated at the 7th post-operative day, through a paper-template method. Group 1 reached an average necrotic area of 48.86%; Group 2, 38.67%; Group 3, 35.34%; and Group 4, 22.61%. After the statistic analysis, results showed that all experimental groups reached statistically significant values when compared to the control group, and Group 4 was the best one, when compared to all groups of this study (P<0.001). The He-Ne laser irradiation was efficient to increase random skin flap viability in rats.