The effect of trimetazidine on the survival of rat island skin flaps subjected to ischemia-reperfusion injury

The effect of trimetazidine (TMZ) on flap ischemia-reperfusion injury was investigated in rat inferior epigastric artery flaps. Twenty-six rats, divided into four experimental groups-nonischemic group (group 1, N = 5), ischemic control group (group 2, N = 7), preischemic TMZ-treated group (group 3, N = 7), and postischemic TMZ-treated group (group 4, N = 7)-were used. Rat inferior epigastric artery flaps were rendered ischemic by occluding the feeding femoral artery, and they were reperfused by releasing the clamps after 11 hours in groups 2 through 4. Group 3 rats were given TMZ (3 mg per kilogram, intravenously) diluted in saline before application of the clamp, and group 4 rats were given TMZ before clamp removal. Flap survival was scored on postoperative day 8. All flaps in the nonischemic control group (group 1) survived completely. The ischemic control group (group 2) demonstrated a 6.3 +/- 4.3% survival area. In the preischemic TMZ group (group 3) the mean survival area was 76.9 +/- 6.1%, and in the postischemic TMZ group (group 4) it was 76.8 +/- 5.6%. TMZ-treated flaps showed a significant increase in survival area regardless of the time of administration (p = 0.001, group 3 vs. group 2; p = 0.001, group 4 vs. group 2). This finding suggests that TMZ has a beneficial effect on the prevention or treatment of arterial ischemic flaps.     

The effect of the microflora in burn wounds on the survival of free skin flaps in autodermoplasty

On the basis of studying the microflora of burn wounds in 112 patients, the dynamics of bacterial contamination of the wounds is shown, the microflora levels, which have the negative effect on survival of the free cutaneous flaps are defined. Gram-negative microflora and streptococcal infection conditioned a failure of the transferred cutaneous flaps in autodermoplasty.     

The effect of hyperbaric oxygen therapy on the survival of random pattern skin flaps in nicotine-treated rats

Previous studies have shown that nicotine increases the risk of necrosis in skin flaps. We investigated the effect of hyperbaric oxygen (HBO(2)) treatment on the survival of random skin flaps in nicotine-treated rats. Thirty-two Sprague-Dawley rats were divided into four groups with eight rats in each group. Group 1 (n=8) was the control, group 2 (n=8) received HBO(2) treatment without being exposed to nicotine, group 3 (n=8) received nicotine and group 4 (n=8) received HBO(2) treatment with exposure to nicotine. The rats in the nicotine-treated groups were prepared by treating them with nicotine for 28 days. At the end of the 28th day, standard McFarlane-type random skin flaps were lifted from the backs of all the rats. In groups 2 and 4, HBO(2) treatment started at the 30th min following the surgery and continued once a day for 7 days. The flap survival rates and histopathological evaluation results related to neovascularisation and granulation tissue formation were significantly better in the HBO(2)-treated groups (groups 2 and 4) than in the groups that did not receive HBO(2) treatment (groups 1 and 3) (p < 0.05). The flap survival rates, neovascularisation and granulation tissue formation were highest in group 2 and lowest in group 3 (p ≤ 0.001). No significant difference was observed between group 4, which received HBO(2) treatment with nicotine exposure, and the control group (group 1) (p > 0.05). In conclusion, our study demonstrates that HBO(2) treatment has a positive effect on flap survival in nicotine-treated rats.     

The effect of desferrioxamine on lipid peroxidation and survival of ischaemic island skin flaps in rats

To produce total necrosis, it was found necessary to subject pedicled groin flaps in rats to 16 hours of warm ischaemia (WI) (whether clamped in situ or removed and maintained at 37 degrees C ex vivo before replantation). Biochemical markers of lipid peroxidation (Schiff bases and thiobarbituric acid (TBA)-reactive material) in homogenates of full thickness skin or of subcutaneous fat rose significantly (p less than 0.001) after 14 hours of WI and reperfusion in vivo. Desferrioxamine (15 mg/kg i.v.) administered systemically either before 14 h WI only, before reperfusion only after 14 h WI or in both circumstances inhibited these rises to near-control (fresh tissue) levels. In survival experiments, this treatment also protected these flaps from necrosis (p less than 0.01).     

前列环素对任意型皮瓣成活影响的实验研究

为观察前列环素(PGI_2)对皮瓣成活的影响,以大白鼠背部设计超长任意型皮瓣模型,设立术前(预防组)、术后(治疗组)静脉给 PGI_2及生理盐水对照组,对皮瓣的血供、代谢和血液流变学等进行分析。结果表明治疗组皮瓣远端血流相对值为41.3%,对照组为22.4%,治疗组皮瓣成活率明显高于对照组,预防组与对照组相比无明显差异。提示:术后早期给予 PGI_2可以改善皮瓣的血流和血液流变状态,提高皮瓣成活面积。     

Effects of clopidogrel on survival of rat skin flaps.

Clopidogrel is a thienopyridine derivative that is chemically related to ticlopidine, which irreversibly inhibits platelet aggregation by selectively binding to adenylate cyclase-coupled adenosine diphosphate receptors on the platelet's surface. In animal models, clopidogrel has been shown to reduce the incidence of both arterial and venous thrombi. In the present study the effects of clopidogrel on the survival of rat epigastric island flaps was researched. Epigastric island flaps of 7x7cm were raised from symphisis pubis to arcus costa with the panniculus carnosus. The experimental group received seven doses of 25mg/kg clopidogrel postoperatively, the first dose given immediately after the suturing of the flaps. The rats were anaesthetised on postoperative day 7 to assess the survival of flaps. The difference between the clopidogrel and the control group was significant (P<0.005). The full-thickness skin samples obtained after the calculation of survival percentages revealed thinning of the epidermis layer and active chronic inflammation in both groups. However, diffuse dilated vessels, extravasated eritrocytes were seen in the clopidogrel group flaps. The results indicated a significant increase in flap survival in rats given clopidogrel. Further research is needed to assess the critical doses of clopidogrel to create optimal flap survival improvement.     

前列环素对任意型皮瓣成活影响的实验研究

为观察前列环素（ＰＧＩ２）对皮瓣成活的影响，以大白鼠背部设计超长任意型皮瓣模型，设立术前（预防组）、术后（治疗组）静脉给ＰＧＩ２及生理盐水对照组，对皮瓣的血供、代谢和血液流变学等进行分析。结果表明治疗组皮瓣远端血流相对值为４１．３％，对照组为２２．４％，治疗组皮瓣成活率明显高于对照组，预防组与对照组相比无明显差异。提示：术后早期给予ＰＧＩ２可以改善皮瓣的血流和血液流变状态，提高皮瓣成活面积。     

紫花烧伤膏对大鼠随意型皮瓣成活的影响

目的 观察紫花烧伤膏对大鼠皮瓣存活的影响,并探讨其作用机制.方法 Wistar 大鼠72只,随机分为紫花组(外用紫花烧伤膏)、阳性对照组(外用海普林乳膏)、阴性对照组(未手术组)和模型组(外用凡士林),每组18只.在大鼠背部设计蒂在头侧的8 cm×2 cm的随意型皮瓣,2次/日涂药,观察大鼠皮瓣成活情况;比较术后1、2、3和7d血清超氧化物歧化酶(SOD)、丙二醛(MDA)、一氧化氮(NO)、肿瘤坏死因子-α(TNF-α)和白细胞介素-6(IL-6)的变化并行组织形态学检查.结果 皮瓣成活面积百分比:紫花组(73.58±10.74)％,模型组(33.40±16.05)％,紫花组比模型组提高了54.61％ (Q =10.63,P＜0.01),与海普林组(71.65±11.92)％比较,差异无统计学意义(P＞0.05);紫花组血清SOD和NO含量高于模型组,MDA、TNF-α和IL-6含量低于模型组(P＜0.01),与海普林组比较,差异无统计学意义(P＞0.05).术后7d紫花组与海普林组皮瓣组织水肿、坏死及炎性细胞浸润较模型组轻,肉芽组织、成纤维细胞增生明显,紫花组有大量新生的毛细血管形成,皮瓣血管所占面积明显高于模型和海普林组(P＜0.01).结论 紫花烧伤膏可明显改善大鼠皮瓣血液循环,提高皮瓣的成活率,其机制可能与抗自由基损害、改善局部微循环、提高NO的含量、降低TNF-α和IL-6水平、减少炎性因子释放,改善氧化应激状态,减轻炎性反应有关.     

前列环素对任意型皮瓣成活影响的实验研究

为观察前列腺素（ＰＧＩ２）对皮瓣成活的影响，以大白鼠背部设计超长任意皮瓣模型，设立术前（预防组），术后（治疗组）静脉给ＰＧＩ２及生理盐水对照组，对皮瓣的血供，代谢和血液流变学等进行分析，结果表明治疗组皮瓣端血流相对值的４１．３％，对照组为２２．４５，治疗组皮瓣成活率明显高于对照组，预防组与对照相比地明显差异，提示：术后早期给予ＰＧＩ２可以改善皮瓣的血流和血液流变状态，提高皮瓣成活面积。     

The effect of scrotal reconstruction with skin flaps and skin grafts on testicular function

Due to its unique composition, the reconstruction of scrotal skin defects is a major clinical challenge. This study was designed to evaluate the effects of scrotal reconstruction, using skin grafts and skin flaps, on spermatogenesis. In Group 1, the rats did not undergo surgery and were used as controls. In Group 2, after removal of all of the scrotal skin to expose the testicles, the defect was repaired using a skin flap from the right groin region. In Group 3, the reconstruction was achieved using skin grafts. All the rats were killed at 2 months postoperatively and evaluated. The mean wet weights of the testicles in the control group were significantly higher compared with that of the graft group. The mean height of the germinal epithelium was significantly greater in the control and flap groups compared with that of the graft group. The Johnsen score for spermatogenesis in the control group was higher than that in the graft group. The use of flaps resulted in testicular function that was comparable to that of the control group, whereas the use of grafts resulted in diminished testicular function. Therefore, we suggest that flaps may be the first choice for scrotal reconstruction.     

The effect of chemical hemodynamic regulation on the survival of arterialized venous flaps

The role of nitric oxide (NO) on the microcirculation of arterialized venous flaps (AVFs) remains controversial. We aimed to investigate the effect of hemodynamic regulation using nitric oxide synthase (NOS) inhibitor and its agonist as a chemical intervention on the survival of AVF. A 10?×?8?cm arterialized venous flap was designed symmetrically on the rabbit abdomen. Thirty-six rabbits were used and randomly divided into three groups: control group, L-arg group and L-NAME group, respectively. The L-arg group and the L-NAME group received intraperitoneal injections of L-arginine (a NOS agonist, 1?g/kg/d) and L-NAME (nitro-L-arginine-methyl ester, a NOS inhibitor, 50?mg/kg/d) respectively, whereas the control group received intraperitoneal injections of the same amount of saline. Flap viability, water content, status of vascular perfusion and gene expression of eNOS and HIF-1α in each group were observed and analyzed. The average value of water content (venous congestion) in the L-arg group was the highest in comparison with the control group and the L-NAME group with a statistically significant difference (all p?相似文献   

The effect of ischemic preconditioning on secondary ischemia in skin flaps

Ischemic preconditioning is a useful manipulation to reduce the undesirable effects of ischemia. The beneficial results of this phenomenon against ischemia-reperfusion have been seen in different flap models; however, all these studies have focused on primary ischemia. In this study, we investigated the effects of ischemic preconditioning on secondary ischemia in a skin flap model. We used the 6- x 3-cm-sized epigastric skin flap in 40 Wistar rats. In all animals, primary global ischemia of 2 hours was followed by 4 hours of either arterial or venous secondary ischemia 24 hours after the primary ischemia and ischemic preconditioning (IP) was tested in this protocol. Ischemic preconditioning was performed by 2 cycles of 15 minutes of repeated ischemia/reperfusion periods. The animals were allocated into 4 groups: group 1 (n = 10 animals): primary ischemia (2 hours) + secondary arterial ischemia (4 hours); group 2 (n = 10 animals): IP + primary ischemia (2 hours) + secondary arterial ischemia (4 hours); group 3 (n = 10 animals): primary ischemia (2 hours) + secondary venous ischemia (4 hours); group 4 (n = 10 animals): IP + primary ischemia (2 hours) + secondary venous ischemia (4 hours). Flap viability was assessed 1 week after the surgical procedure, and surviving flap area was recorded as a percentage of the whole flap area. Group 1 was compared with group 2, and group 3 was compared with group 4 to evaluate the effects of ischemic preconditioning against secondary arterial and venous ischemia. t test and Mann-Whitney rank sum tests were used for statistical analysis. There were statistical differences both between groups 1 and 2 and groups 3 and 4. The results revealed that ischemic preconditioning was an effective procedure to reduce the flap necrosis as a cause of secondary ischemia in skin flaps.     

A comparative study on the effect of various pharmacological agents on the survival of skin flaps in the rat.

The effects of chlorpromazine, pentoxifylline, terbutaline, allopurinol, phenoxybenzamine, naftidrofuryl, hydralazine and trimetazidine were investigated on caudally based dorsal flaps. The study was performed on 108 rats, divided in 9 groups of 12 animals each, one of which served as a control group. All treated groups showed a significantly greater survival of the flap than the control group. Comparisons among different groups showed better outcome in those receiving trimetazidine and hydralazine, followed by those receiving naftidrofuryl and phenoxybenzamine.     

Verapamil improves survival of rat hyperemic island skin flaps

Inability to maintain cellular calcium homeostasis is a critical factor in the pathogenesis of cellular ischemic injury and may mediate oxygen radical release in the reperfusion period. We assessed the effect of the selective calcium channel blocker verapamil on the performance of rat hyperemic island skin flaps. Pretreatment with verapamil markedly improved survival of skin flaps after 6 hours of venous cross-clamping compared with animals receiving placebo only (99% vs 53.3%; p less than 0.01). Verapamil also prevented the formation of lipid peroxidation products and the depletion of the endogenous antioxidant glutathione, suggesting that the beneficial effect of verapamil is the result of protection against oxygen radical injury. After 12 hours of venous cross-clamping, verapamil did not improve survival of skin flaps despite protection against lipid peroxidation. Oxygen radical release is therefore a crucial event in the pathogenesis of skin flap necrosis after short-term ischemia but is of less significance in long-term ischemia.     

Remote ischemic preconditioning improves the survival of rat random-pattern skin flaps

Random-pattern flap transfer is one of the most popular procedures for covering soft tissue defects. Ischemic preconditioning is a protective endogenous mechanism capable of reducing ischemia-reperfusion injury, and it has been shown that preconditioning by proximal pedicle clamping can improve flap survival. However, the method is not suitable for random-pattern flap transfer in the clinical setting. The present study evaluates the effect of ischemic preconditioning of Wistar rat hind limbs upon dorsal random-pattern skin flap survival. Ischemic preconditioning was induced by ischemia of the right hind limb during 10 min, followed by 30 min of reperfusion. Thirty-two animals were divided in two groups. In group 1, a dorsal random-pattern skin flap measuring 2 × 7 cm was raised immediately after the induction of ischemic preconditioning. The animals in group 2 (controls) received the same treatment, but without ischemic preconditioning. The survival area was defined as the surface of the viable tissue (square centimeter) on the fifth postoperative day. The average survival area was 6.57 ± 0.18 cm² in group 1 and 4.44 ± 0.21 cm² in group 2. All preconditioned animals presented significantly higher flap survival areas than the controls (p ≤ 0.01, Student’s t test). Our findings show that flap necrosis was reduced by the induction of ischemic preconditioning in a body area distant from the flap harvest site, and that ischemic preconditioning has a systemic protective effect on dorsal random-pattern skin flaps and increase survival. A better understanding of the mechanism involved may improve the clinical condition of patients requiring random-pattern skin flap transfer, especially in high-risk groups.