Buflomedil and pentoxifylline in the viability of dorsal cutaneous flaps of rats treated with nicotine

The Effects of Sildenafil and/or Nitroglycerin on Random-pattern Skin Flaps After Nicotine Application in Rats

Smoking aggravates skin necrosis as a complication of random-pattern flap ischaemia. Sildenafil and nitroglycerin (NTG) are vasodilator agents that may affect skin flap survival. Fifty rats were subjected to a dorsal random-pattern flap operation and randomly divided into 5 groups. The control group received no treatment. The ischaemic group were administered local nicotine injections. The sildenafil group were administered oral sildenafil treatment in addition to the same intervention as the ischaemic group. The NTG group received topical NTG ointment application instead of sildenafil. The combined group were given both sildenafil and NTG treatments. After 7 days, all rats were sacrificed for flap assessment. Flap survival percentages at the 3^rd and 7^th days were significantly higher in the combined group than in the other study groups. Histologically, the ischaemic group exhibited dermal disorganization and inflammatory cell infiltration, which were improved in the 3 treated groups; however, the combined group presented the most relevant effect. The epidermal thickness showed a decrease in the ischaemic group (23.1 μm) that was significantly increased in the sildenafil (28.4 μm), NTG (28.8 μm) and combined (35.8 μm) groups. Immunohistochemically, the combined group exhibited a significant decrease in the apoptotic index and an increase in the proliferative index (2.3 and 56.9%, respectively) compared to those in the ischaemic (63.2 and 3%), sildenafil (41.7 and 28.1%) and NTG (39.3 and 30.4%) groups. Transmission electron microscopy (TEM) showed that the combined group displayed improvement in most of the ischaemic changes. Our analyses suggest that the combined use of sildenafil and NTG is more efficacious than using only one of these treatments for skin flap survival.

Comparison of Prostaglandin E1 and Sildenafil Citrate Administration on Skin Flap Survival in Rats

Background

Alprostadil and sildenafil are known vasodilators used independently to improve flap survival in animal models. In this study, we investigate whether these agents act synergistically to decrease flap necrosis in rat models.

Methods

After acclimation period, 4 groups of 10 male white rats were given a modified McFarlane skin flap. The postoperative treatment included saline control (Group A), sildenafil citrate-only (Group B), alprostadil-only (Group C), and both sildenafil and alprostadil (Group D). The flaps were observed on postoperative days 1, 3, 5 and 7. The animals were euthenized on postoperative day 7, and the flaps were evaluated for inflammation and neovascularization.

Results

At each observation, the mean necrotic index was significantly lower for all three treatment groups (Groups A, B, C) and was the lowest for the combined treatment group. On histologic evaluations, combined treatment was associated with decreased inflammation and increased capillary vessel formation, when compared with control group.

Conclusion

Both sildenafil-only and alprostadil treatments were independently associated with increased flap survival rate. Sildenafil citrate and alprostadil had a synergistic effect in increasing flap survival rate.

Effect of side-stream smoking on random-pattern skin flap survival in rats

The secondhand exposure to cigarette smoke is being considered evil, and damage caused by this passive exposure has been proven by several studies. To investigate the effects of sidestream smoke exposure on random-pattern skin flap survival, 20 female rats were separated into 2 groups: group A (n = 10) was exposed 6 weeks to the smoke from the burning cigarette (passive smoking) and group B (n = 10) was the control group. After 6 weeks of exposition, a dorsal McFarlane flap of 4 × 10 cm was performed in all rats. Two weeks after this procedure, the ratio of necrotic and total areas was calculated using computer programs. The median area of necrosis in group A was 29.5%, significantly higher than that in group B with 17.5% (P < 0.024). In conclusion, this study suggests increased risk of random-pattern skin flap necrosis after sidestream exposure to cigarette smoke.

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

INTRODUCTION

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.

MATERIALS AND METHODS

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.

RESULTS

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).

CONCLUSIONS

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.

The effect of TENS on random pattern flap survival in nicotinized rats

The adverse effects of cigarettes, due to their nicotine content, may cause important ischemic complications in flaps. Electrical stimulation increases blood flow in ischemic tissues, the level of vascular endothelial growth factor, capillary density, and angiogenesis while decreasing oxygen tension in tissues. Electrical stimulation is also known to increase survival rate in flaps. In this study, which tests the hypothesis that TENS (a type of electrical stimulation) contributes to enhancement of flap viability by eliminating the adverse effects of nicotine, 40 rats were divided into 4 groups of 10 rats. Nicotinization was achieved by subcutaneous administration of 2 mg/kg per day to the rats, other than those in the Control group, for 4 weeks. The rats in one of the nicotinized groups received 20 mA, 80 Hz TENS (TENS1 group) for 1 hour daily throughout the last week before McFarlane flaps of random pattern were made in the backs of all the rats. Another nicotinized group was subjected to TENS in a similar dose after flap elevation (TENS2 group). Flap blood flow was measured before and 48 hours after their construction, and their fluorescein perfusion was measured immediately after the flap elevation. The comparison of the survival rates of the flaps revealed that, although the blood flow in the Nicotine group was significantly lower than in the Control group, it was significantly higher in the TENS1 group than in both the Control and Nicotine groups. The proportion of the area stained with fluorescein, immediately after the elevation of flaps, was significantly reduced in the Nicotine group compared to the Control group. In the TENS1 group, however, it was greater than in the nicotine and TENS2 groups. Flap viability rates decreased significantly in the Nicotine group compared with the Control group. In the TENS2 group, however, an increase was observed compared with the Nicotine group.These findings suggest that although TENS performed before flap elevation does not contribute to flap survival, despite causing a rise in blood flow, it enhances flap survival when applied postoperatively. Given the practicality and low cost of TENS, it can be concluded that it may be possible to use it in the management of ischemic complications in flap operations in smokers.

Vasoactive agent buflomedil up-regulated expression of vascular endothelial growth factor in a rat model of sciatic nerve crush injury

Objectives:

To study the effect of Buflomedil on the morphological repair on crush injury of sciatic nerve and also the expression of vascular endothelial growth factor (VEGF).

Materials and Methods:

Rat sciatic nerves were crushed by pincers. All of the 400 Sprague Dawley rats were randomly divided into: Sham-operated; saline; saline + VEGF-antibody; Buflomedil; and Buflomedil + VEGF antibody groups. The expression of VEGF in dorsal root ganglia (DRGs), following crush injury to sciatic nerves, was studied by RT-PCR, immunohistochemistry. The effects of Buflomedil on expression of VEGF and repair of neural pathology were also evaluated.

Results:

VEGF mRNA was significantly increased in Buflomedil and Buflomedil + VEGF-antibody groups, compared with other groups. The number of VEGF-positive neurons was significantly increased in the Buflomedil and the saline groups. Besides, Buflomedil also caused less pathological changes in DRGs.

Conclusions:

The vasoactive agent Buflomedil may decrease the pathological lesion and improve the functional rehabilitation of peripheral nerves, which may correlate to upregulation of the expression of VEGF, following crush injury to the peripheral nerves.

Effects of sildenafil on the viability of random skin flaps

PURPOSE: To assess the viability of McFarlane skin flaps in rats with administration of sildenafil. METHODS: Twenty Wistar rats were distributed into two groups: Control (dorsal skin flap, subdermal application of saline solution at 0.9%) and Study (dorsal skin flap, subdermal application of sildenafil). Seven days after the surgery, flaps were photographed and graphically rendered. Then, they were analyzed with AutoCAD software. Three biopsies (proximal, medial and distal) of each flap were collected for histological analysis. RESULTS: Macroscopic analysis showed that animals of the study group had greater necrotic areas (p=0.003) in the dorsal skin flaps. Additionally, histological analysis of the distal third of these flaps showed a tendency to less granulated tissue formation in animals treated with sildenafil. CONCLUSION: Sildenafil subdermally was associated with lower viability of the random skin flap in rats.

Avaliação citométrica dos adipócitos localizados no tecido subcutâneo da parede anterior do abdome após infiltração percutânea de CO2

OBJETIVO: Avaliar os efeitos da infiltração de dióxido de carbono em adipócitos presentes na parede abdominal. MÉTODOS: Quinze voluntárias foram submetidas a sessões de infusão de CO2 durante três semanas consecutivas (duas sessões por semana com intervalos de dois a três dias entre cada sessão). O volume de gás carbônico infundido por sessão, em pontos previamente demarcados, foi sempre calculado com base na superfície da área a ser tratada, com volume infundido fixo de 250 mL/100cm² de superfície tratada. Os pontos de infiltração foram demarcados respeitando-se o limite eqüidistante 2cm entre eles. Em cada ponto se injetou 10mL, por sessão, com fluxo de 80mL/min. Foram colhidos fragmentos de tecido celular subcutâneo da parede abdominal anterior antes e após o tratamento. O número e as alterações histomorfológicas dos adipócitos (diâmetro médio, perímetro, comprimento, largura e número de adipócitos por campos de observação) foram mensurados por citometria computadorizada. Os resultados foram analisados com o teste t de Student pareado, adotando-se nível de significância de 5% (p<0,05). RESULTADOS: Encontrou-se redução significativa no número de adipócitos da parede abdominal e na área, diâmetro, perímetro, comprimento e largura após o uso da hipercapnia (p=0,0001). CONCLUSÃO: A infiltração percutânea de CO2 reduz a população e modifica a morfologia dos adipócitos presentes na parede abdominal anterior.

Effects of pentoxyfilline and heparin on reperfusion injury island skin flaps in rats exposed to tobacco

BACKGROUND

Ischemia-reperfusion injury is believed to be a major cause of transferred skin flap failure. Cigarette smoking is known to be associated with endogenous antioxidant depletion, hypercoagulability, and cutaneous vasoconstriction. This investigation was carried out to study possible effects of pentoxyfilline or heparin on rat skin reperfusion injury under tobacco exposure.

MATERIALS AND METHODS

Thirty-six rats were randomized into two major groups: 18 were exposed to cigarette smoke during a 4 wk period prior to surgery; the remaining 18 underwent a sham smoking procedure. Each group was further divided into three equal subgroups: heparin, pentoxyfilline, and saline solution. One identical skin flap was raised in each animal. The vasculature of the flap was clamped for 3 h and reperfused for 5 min. A venous blood sample was obtained from the flap after reperfusion for serum malondialdehyde (MDA) and myeloperoxidase (MPO) analysis. Flap survival was assessed 7 d after the procedure.

RESULTS

The lipid peroxidation levels and flap necrosis were significantly higher in the cigarette-smoking group skin flaps. There was also a decrease of MPO activity in this group compared with the non-smoking group. Heparin-treated rats had significantly lower MDA levels and showed the most viable percent area among smoking rats.

CONCLUSIONS

These data suggest that heparin had a significant beneficial effect both on flap survival and on the lipid peroxidation reduction after smoke exposure in the rat axial-pattern skin flap subjected to ischemia and reperfusion injury. Pharmacologic therapy may represent an alternative way to counteract tobacco effects in flap surgery in emergency situations.

Effects of buflomedil and pentoxifylline on hamster skin-flap microcirculation: prediction of flap viability using orthogonal polarization spectral imaging

OBJECTIVE

This study investigated the effects of buflomedil and pentoxifylline, both of which are used in reconstructive surgery of hamster skin flap microcirculation, and evaluated the skin flap survival rate by orthogonal polarization spectral imaging.

METHOD

Twenty-four adult male Syrian golden hamsters were divided into three groups: a control (C, 0.1 ml 0.9% saline), buflomedil (B, 3 mg/kg/day), and pentoxifylline group (P, 14.5 mg/kg/day). Treatments administered intraperitoneally were initiated 1 hour before skin flap preparation and continued for 7 days post-operatively at 12-hour intervals. Preparations (skin flaps) were divided into 12 fields, which were organized into six bands. Functional capillary density (FCD, in mm/mm(2)), distance from the skin flap base to blood flow cessation (Dist(with flow), in cm), percentage of viable skin (VA, in%), and qualitative analysis of blood flow by orthogonal polarization spectral imaging were performed at 1 and 24 hours and on the seventh post-operative day.

RESULT

Bands IV, V, and VI presented no flow independent of time. The functional capillary density group B was higher than that of groups C and P, primarily after 24 hours. All groups showed an increase in D with time but reached similar final distances (C = 2.73, B = 2.78 and P = 2.70 cm). Moreover, the percentage of viable areas remained at approximately 50%. The orthogonal polarization spectral imaging was useful to assess viability by counting fields with and without blood flow.

CONCLUSIONS

Functional capillary density values were higher in the buflomedil group compared to the control and pentoxifylline groups in this model. Functional capillary density did not influence D or the percentage of VA, and the technique showed favorable potential to assess/predict the viability of skin flaps within 1 h after surgery.

The use of buflomedil in reduction mammaplasty for a previously irradiated breast: a case report

In recent years, lumpectomy combined with breast irradiation and chemotherapy, as a part of conservation therapy for breast cancer, has well-established results. Little has been published on reduction mammoplasty for breast-irradiated patients. These patients have increased risks of nipple necrosis, wound complications, and delayed healing. Breast reduction techniques that rely on minimum skin undermining combined with the use of buflomedil may prevent major postoperative complications in breast-irradiated patients. Buflomedil was administered intraoperatively and for 14 days after the procedure. The use of buflomedil in reduction mammaplasty for a previously irradiated breast patient has not been heretofore described. The case of a 58-year-old woman who underwent bilateral breast reduction after breast conservation therapy is reported.