Ischemia-Reperfusion Injury of Adipofascial Tissue: An Experimental Study Evaluating Early Histologic and Biochemical Alterations in Rats

Fat necrosis remains a serious complication in reconstructive flaps. In clinical setting, it is well known that fat tissue is more susceptible to ischemic events. We aimed to evaluate early histological and biochemical changes of adipofascial tissue in an experimantal model. An epigastric flap model in rats was used to evaluate the effect of ischemia-reperfusion (I-R) injury on adipofascial tissue. Two groups of animals (one with ischemia alone and other ischemia-reperfusion group) were used to evaluate the degree of histological edema, congestion and extravascular bleeding, and early biochemical alterations within the adipofascial flaps. The biochemical parameters included glutathione (GSH) and malondialdehyde (MDA). In each group, contralateral groin subcutaneous adipose tissue served as control. These evaluations were compared to normal unmanipulated, contralateral abdominal subcutaneous adipose tissue. The ischemia-reperfused flap group showed histologically significantly much edema congestion and bleeding than the control groups (P < .0001). The control group showed less edema in fat tissue than the ischemia-alone group (P < .05). All of the flaps in the ischemia-only group showed significantly less bleeding and edema than I-R group (P < .001). The ratio of MDA/GSH was 33 in control, 37 in ischemia alone, and 82 in ischemia-reperfusion groups, respectively. This study confirms that significant histologic and biochemical alteration occurs after ischemia and ischemia-reperfusion events in adipose tissue. Marked drop in adipose tissue antioxidant levels after I-R suggested that preemptive measures to this decrease should be undertaken in clinical settings

Gelatin-Sealed Dacron Graft is not more Susceptible to MRSA Infection than PTFE Graft

ObjectivesThe purpose of this experimental study was to compare the susceptibility of gelatin-sealed Dacron and PTFE prostheses to infection by MRSA.DesignProspective, randomized, controlled animal study.Materials and MethodsGraft infections were established in the subcutaneous tissues of 60 female Spraque-Dawley rats by the implantation of gelatin-sealed Dacron or PTFE prostheses followed by topical inoculation with methicillin-resistant Staphylococcus aureus. The study groups were as follows: (1A) uncontaminated gelatin-sealed Dacron group, (1B) untreated contaminated gelatin-sealed Dacron group, (1C) contaminated gelatin-sealed Dacron group with intraperitoneal teicoplanin treatment, (2A) uncontaminated PTFE group, (2B) untreated contaminated PTFE group, and (2C) contaminated PTFE group with intraperitoneal teicoplanin treatment. The grafts were removed after 7 days and evaluated for infection by counting the number of adherent bacteria on the graft material after rinsing and sonication. The perigraft tissue was harvested for histopathological study. To investigate the existence of any infection, blood samples were collected by cardiopuncture for a culture analysis.ResultsNo significant difference in bacteria counts was observed between gelatin-sealed Dacron and PTFE grafts. In groups 1A and 2A, there was no infection detected. The bacterial counts for MRSA were 7.4×105 in group 1B and 8.6×105 in group 2B. There was also no infection in groups 1C and 2C. While the difference between group 1B and 2B was not significant (p>.05), bacterial counts in group 1B or 2B were significantly higher than those in other groups. Blood cultures were only positive in four rats in group 1B and in two rats in group 2B. The severities of the inflammation of the perigraft tissues was low in groups 1A and 2A, high in groups 1C and 2C, and between the range from low to moderate in groups 1B and 2B.ConclusionThe susceptibility of gelatin-sealed Dacron to bacterial infection was not higher than that of PTFE

The protective effect of ischemic preconditioning on rat testis

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Ischemic preconditioning reduces the severity of ischemia-reperfusion injury of peripheral nerve in rats

<p>Abstract</p> <p>Background and aim</p> <p>Allow for protection of briefly ischemic tissues against the harmful effects of subsequent prolonged ischemia is a phenomennon called as Ischemic Preconditioning (IP). IP has not been studied in ischemia-reperfusion (I/R) model of peripheral nerve before. We aimed to study the effects of acute IP on I/R injury of peripheral nerve in rats.</p> <p>Method</p> <p>70 adult male rats were randomly divided into 5 groups in part 1 experimentation and 3 groups in part 2 experimentation. A rat model of severe nerve ischemia which was produced by tying iliac arteries and all idenfiable anastomotic vessels with a silk suture (6-0) was used to study the effects of I/R and IP on nerve biochemistry. The suture technique used was a slip-knot technique for rapid release at time of reperfusion in the study. Cytoplasmic vacuolar degeneration was also histopathologically evaluated by light microscopic examination in sciatic nerves of rats at 7th day in part 2 study.</p> <p>Results</p> <p>3 hours of Reperfusion resulted in an increase in nerve malondialdehyde levels when compared with ischemia and non-ischemia groups (p < 0.001 and p < 0.0001 respectively). IP had significantly lower nerve MDA levels than 3 h reperfusion group (p < 0.001). The differences between ischemic, IP and non-ischemic control groups were not significant (p > 0.05). There was also a significant decrease in vacoular degeneration of sciatic nerves in IP group than I/R group (p < 0.05).</p> <p>Conclusion</p> <p>IP reduces the severity of I/R injury in peripheral nerve as shown by reduced tissue MDA levels at 3 th hour of reperfusion and axonal vacoulization at 7 th postischemic day.</p