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PURPOSE: To compare the inflammatory response of three different meshes on abdominal hernia repair in an experimental model of incisional hernia. METHODS: Median fascial incision and skin synthesis was performed on 30 Wistar rats. After 21 days, abdominal hernia developed was corrected as follows: 1) No mesh; 2) Polypropylene mesh; and, 3) Ultrapro(r) mesh. After 21 days, the mesh and surrounding tissue were submitted to macroscopic (presence of adhesions, mesh retraction), microscopic analysis to identify and quantify the inflammatory and fibrotic response using a score based on a predefined scale of 0-3 degrees, evaluating infiltration of macrophages, giant cells, neutrophils and lymphocytes. RESULTS: No significant difference was seen among groups in adherences, fibrosis, giant cells, macrophages, neutrophils or lymphocytes (p>0.05). Mesh shrinkage was observed in all groups, but also no difference was observed between polypropylene and Ultrapro mesh (7.0±9.9 vs. 7.4±10.1, respectively, p=0.967). Post-operatory complications included fistula, abscess, dehiscence, serohematic collection and reherniation, but with no difference among groups (p=0.363). CONCLUSION: There is no difference between polypropylene (high-density) and Ultrapro(r) (low-density) meshes at 21 days after surgery in extraperitoneal use in rats, comparing inflammatory response, mesh shortening, adhesions or complications.

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PURPOSE: To investigate the structural and functional changes induced by corticosterone (CORT) in the ventral prostrate (VP) of rats in order to study chronic stress effects in the prepubertal phase. METHODS: Wistar rats received daily saline or CORT injections during the pubertal period from the 5th to 25th day of postnatal life. The animals were distributed into four groups: 1 - Control (n=5); 2 - Control 99mTc-P (n=5); 3 - Treated with CORT (n=14); 4 - Treated with CORT and 99mTc-P (n=10). All rats were sacrificed at two months of age. Technical tissue uptakes of 99mTc-P were used to evaluate the functional and stereological methods for morphological analysis. RESULTS: Acini distribution in the group treated with CORT differed significantly (p<0.0001) from the control. The control group's epithelial average height (10.01±0.24 microns) was statistically significant (p<0.0001) from rats treated with CORT (19.27±0.73microns). The collagen distribution was lower in the treated group (2.79%) when compared to control (3.97%). The radioactivity percentage in the groups marked with 99mTc-P (%Ati/g) did not demonstrate a statistically significant difference (p=0.285897). CONCLUSION: Chronic administration of corticosterone in prepubertal rats causes changes in their acinar structure and their ventral prostate stroma, indicating possible deleterious effects of this hormone.

Resumo em Inglês:

PURPOSE: To evaluate the heart and the Tc-99m-sestamibi biodistribution after statin pretreatment in a rat model of abdominal sepsis. METHODS: Twenty-four Wistar rats were randomly distributed into four groups (n=6 per group): 1) sepsis with simvastatin treatment, 2) sepsis with vehicle, 3) sham control with simvastatin and 4) sham control with vehicle. 24 hours after cecal ligation and puncture rats received 1.0MBq of Tc-99m-sestamibi i.v. 30min after, animals were euthanized for ex-vivo tissue counting and myocardium histological analysis. RESULTS: Myocardial histologic alterations were not detected 24 hours post-sepsis. There was significantly increased cardiac Tc-99m-sestamibi activity in the sepsis group with simvastatin treatment (1.9±0.3%ID/g, p<0.001) in comparison to the sepsis group+vehicle (1.0±0.2%ID/g), control sham group+ simvastatin (1.2±0.3%ID/g) and control sham group (1.3±0.2%ID/g). Significant Tc-99m-sestamibi activity in liver, kidney and lungs was also detected in the sepsis group treated with simvastatinin comparison to the other groups. CONCLUSIONS: Statin treatment altered the biodistribution of Tc-99m-sestamibi with increased cardiac and solid organ activity in rats with abdominal sepsis, while no impact on controls. Increased myocardial tracer activity may be a result of a possible protection effect due to increased tissue perfusion mediated by statins.

Resumo em Inglês:

PURPOSE: To evaluate the central nervous system toxicity of cisplatin and neuroprotective effect of selenium. METHODS: Twenty-one male Wistar albino rats were divided into three groups: control (C), cisplatin (CS), cisplatin and selenium (CSE, n=7 in each group). Cisplatin (12 mg/kg/day, i.p.) was administered to CS and CSE groups for three days. Furthermore, CSE group received 3mg/kg/day (twice-a-day as 1.5 mg/kg) selenium via oral gavage five days before cisplatin injection and continued for 11 consecutive days. The same volumes of saline were administered to C group intraperitoneally and orally at same time. RESULTS: Heterochromatic and vacuolated neurons and dilated capillary vessels in the brain were observed in the histochemical examinations of cisplatin treated group. Rats that were given a dose of 3mg/kg/day selenium decreased the cisplatin induced histopathological changes in the brain, indicating a protective effect. In addition, cytoplasmic staining of the cell for bcl-2, both cytoplasmic and nuclear staining for bax were determined to be positive in the all groups. Bax positive cells were increased in the CS group compared to C group, in contrast to decreased bcl-2 positivity. CONCLUSION: Selenium limited apototic activity and histological changes due to the cisplatin related central neurotoxicity.

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PURPOSE: To extract the Melaleuca sp. oil and to assess its in vitro inhibitory effect against Staphylococcus aureus isolates obtained from lower limb wounds and resistant to several antibiotics. METHODS: A total of 14 test-tubes containing Mueller-Hinton broth were used to determine the Minimum Inhibitory Concentration (MIC). The following concentrations of the Melaleuca sp. oil were added to the first 11 tubes: 8; 4; 2; 1; 0.5; 0.2; 0.1; 0.05; 0.025; 0,0125 and 0.00625%. The 12th and 13th tubes, with and without oil, were used as the positive and negative controls, respectively. The experimental study was carried out in triplicate at 37ºC for 18 hours. The Minimum Bactericidal Concentration (MBC), able of killing all the microorganisms, was also determined. Two S. aureus isolates were obtained from lower limb wounds of female patients and the identification of the microorganisms (Staphylococcus aureus) and the test for susceptibility to the antimicrobial agents were carried out by automation using the apparatus MicroScan(r). After identification, the isolates were preserved in liquid Trypticase Soy medium, and inoculated for determination of the MIC and MBC. RESULTS: The MIC was 0.2% and the MBC was 0.4%. CONCLUSION: The Melaleuca sp. oil showed antimicrobial properties in vitro against strains isolated from lower limb wounds which were resistant to multiple antibiotics.

Resumo em Inglês:

PURPOSE: Vogt´s antioxidant solution (red blood cells, Ringer's solution, sodium bicarbonate, mannitol, allopurinol and 50% glucose) or its modification including hydroxyethyl starch (HES) were tested for the prevention of splanchnic artery occlusion shock. METHODS: Seventy rats were distributed in treatment (3), control (1), and sham (3) groups. Ischemia and reperfusion were induced by celiac, superior mesenteric and inferior mesenteric arteries occlusion for 40 min, followed by 60 min reperfusion or sham procedures. Controls received saline, both treatment and sham groups received the Vogt's solution, modified Vogt's solution (replacing Ringer's solution by HES), or HES. Mean arterial blood pressure (MABP), ileal malondialdehyde (MDA) and plasmatic MDA were determined, and a histologic grading system was used. RESULTS: At reperfusion, MABP dropped in all I/R groups. Only HES treatment was able to restore final MABP to the levels of sham groups. Plasmatic MDA did not show differences between groups. Ileum MDA was significantly higher in the control and treatment groups as compared to the sham group. Histology ranking was higher in the only in control group. CONCLUSIONS: Hydroxyethyl starch was able to prevent hemodynamic shock but not intestinal lesions. Both treatments with Vogt's solutions did not show any improvement.

Resumo em Inglês:

PURPOSE: To investigate the protective effect of dexmedetomidine (Dex) on testicular damage induced by ischemia-reperfusion injury in rats. METHODS: Sham group underwent left scrotal exploration only (group 1). The ischemia-reperfusion only group underwent left testicular torsion and detorsion (group 2). The ischemia-reperfusion plus Dex group underwent left testicular torsion, received 50 µg/kg Dex (group 3) and 100 µg/kg Dex (group 4) intraperitoneally at minute 180 of ischemia and then underwent detorsion. We determined histopathological findings and performed specific biochemical analyses. RESULTS: Increasing doses of Dex significantly increased TAS, and significantly decreased OSI. Analyzing the antioxidant effects of increasing doses of Dex in torsion and contrlateral testicles: Dex 100 µg/kg statistically significant increased the tissue total antioxidant status (TAS) and oxidative stress index (OSI) when compared with Dex 50 µg/kg but not found significantly change on the tissue total oxidant status (TOS). However, Dex did not significantly improve these histological alterations. CONCLUSION: The antioxidant effects of dexmedetomidine on testicular ischemia-reperfusion injury in ipsilateral and contrlateral testis, but in the histopathological level, there was no difference statistically according to Johnsen's scoring system between groups at both sides.

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PURPOSE: To investigate if oxymatrine pretreatment could ameliorate renal I/R injury induced in rats and explore the possible role of oxymatrine in Nrf2/HO-1 pathway. METHODS: Unilaterally nephrectomized rats were insulted by I/R in their left kidney. Twenty four rats were randomly divided into three groups: sham group, I/R + saline-treated group, I/R + OMT-treated group. Oxymatrine or vehicle solution was administered intraperitoneally injected 60 min before renal ischemia, respectively. Renal function, histology, makers of oxidative stress, cell apoptosis and Nrf2/HO-1 expressions were assessed. RESULTS: Oxymatrine pretreatment exhibited an improved renal functional recovery, alleviated histological injury and oxidative stress, inhibiting tubular apoptosis, and accompanied by upregulated the expression of Nrf2/HO-1 proteins. CONCLUSION: Oxymatrine may attenuate renal ischemia/reperfusion injury, and this renoprotective effect may be through activating the Nrf2/HO-1 pathway.

Resumo em Inglês:

PURPOSE: To examine the effects of the oil mixes (ω-9, ω-6 and ω-3) in rats subjected to thermal burn. It was also aimed to assess whether the sources of ω3 would interfere with the effect of such mixes on the thermal injury. METHODS: Thirty-six rats distributed into five groups: burned + water, burned + isolipid mix, burned + oil mix 1 (ALA), burned + oil mix 2 (ALA + EPA + DHA of fish) and burned + oil mix 3 (ALA + DHA from seaweed). The thermal injury was involving total thickness of skin. After the burns animals received the oil mixes for seven days. The lesions were evaluated by immunohistochemistry. RESULTS: Animals receiving mix 3 showed a smaller extension of the thermal injury as compared to those that were supplemented with other oils mixes. Expression of Ki-67 in the receiving Mix 3 increased as compared to all the other groups. Animals supplemented with mix 3 were able to inhibit NF-κB in injured tissue. CONCLUSION: Rats received oil mix in which the source of ω3 (ALA+DHA of seaweed) showed inhibition of NF-κB, increase in cell proliferation, and reduction the extension of thermal lesion.

Resumo em Inglês:

PURPOSE: To evaluate whether post-hemorrhagic shock mesenteric lymph (PSML) is involved in cardiac dysfunction induced by hemorrhagic shock. METHODS: The hemorrhagic shock model (40±2 mmHg, 3h) was established in rats of the shock and shock+drainage groups; and PSML drainage was performed from hypotension 1-3h in the shock+drainage rats. Then, the isolated hearts were obtained from the rats for the examination of cardiac function with Langendorff system. Subsequently, the isolated hearts were obtained from normal rats and perfused with PSML or Krebs-Henseleit solution, and the changes of cardiac function were observed. RESULTS: The left ventricular systolic pressure (LVSP) and the maximal rates of LV developed pressure (LVDP) rise and fall (±dP/dt max) in the shock and shock+drainage groups were lower than that of the sham group; otherwise, these indices in the shock+drainage group were higher compared to the shock group. In addition, after isolated hearts obtained from normal rats perfusing with PSML, these cardiac function indices were gradual decline along with the extension of time, such as heart rate, LVSP, ±dP/dt max, etc. CONCLUSION: Post-hemorrhagic shock mesenteric lymph is an important contributor to cardiac dysfunction following hemorrhagic shock.