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ABSTRACT Purpose: To investigate the protective effect of parecoxib against lung ischemia-reperfusion injury (LIRI) in rats and the mechanism. Methods: Thirty rats were divided into sham-operated, LIRI and LIRI+parecoxib groups. LIRI model (ischemia for 60 min, followed by reperfusion for 120 min) was constructed in LIRI and LIRI+parecoxib groups. In LIRI+parecoxib group, 10 mg/kg parecoxib was given via femoral vein 15 min before ischemia beginning. At the end of the reperfusion, blood gas analysis, lung wet to dry mass ratio measurement, lung tissue biochemical determination and heme oxygenase-1 (HO-1) protein expression determination were performed. Results: Compared with LIRI group, in LIRI+parecoxib group the oxygenation index was significantly increased, the alveolar-arterial oxygen partial pressure difference was significantly decreased, the lung wet to dry mass ratio was significantly decreased, the lung tissue malondialdehyde content was significantly decreased, the lung tissue superoxide dismutase and myeloperoxidase activities were significantly increased, the lung tissue tumor necrosis factor α and interleukin 1β levels were significantly decreased, and the lung tissue HO-1 protein expression level was significantly increased (all P < 0.05). Conclusions: Parecoxib pretreatment can mitigate the LIRI in rats by reducing oxidative stress, inhibiting inflammatory response and up-regulating HO-1 expression in lung tissue.

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ABSTRACT Purpose: To investigate experimentally the effects of Tropifexor, a farnesoid X receptor agonist, on liver injury in rats with obstructive jaundice. Methods: Forty healthy Wistar albino female rats were divided randomly in selected groups. These groups were the sham group, control group, vehicle solution group, Ursodeoxycholic acid group and Tropifexor group. Experimental obstructive jaundice was created in all groups, except the sham one. In the blood samples obtained, aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), gamma-glutamyl transferase (GGT), total bilirubin and direct bilirubin levels were established and recorded. Additionally, liver malondialdehyde, myeloperoxidase and catalase enzyme activity in the tissue samples were studied. Histopathological analysis was also performed. Results: No statistical difference was found between the control group and the Tropifexor group when AST, ALT and ALP values were compared. However, it was found that the Tropifexor group had statistically significant decreases in the values of GGT, total bilirubin and direct bilirubin (p < 0.05). Additionally, Tropifexor decreased the median values of malondialdehyde and myeloperoxidase, but this difference was not statistically significant compared to the control group. Finally, the Tropifexor group was statistically significant in recurring histopathological liver damage indicators (p < 0.05). Conclusions: Tropifexor reduced liver damage due to obstructive jaundice.

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ABSTRACT Purpose: To evaluate if the perconditioning affects the antioxidant capacity in mesenteric ischemia and reperfusion injury. Methods: Twenty-one Wistar rats were assigned into three groups, as follows: Sham, IR and rPER. The animals were subjected to mesenteric ischemia for 30 min. rPER consisted of three cycles of 5-min hindlimb ischemia followed by 5 min hindlimb perfusion at the same time to mesenteric ischemic period. After 5 minutes, blood and 5 cm of terminal ileum were harvested for thiobarbituric acid reactive substances (TBARS) and Trolox equivalent antioxidant capacity (TEAC) measurement. Results: rPER technique was able to reduce intestinal tissue TBARS levels (p<0.0001), but no statistic difference was observed in blood levels between groups, although it was verified similar results in rPER and Sham group. rPER technique also enhanced TEAC levels in both blood (p = 0.0314) and intestinal tissue (p = 0.0139), compared to IR group. Conclusions: rPER appears as the most promising technique to avoid IR injury. This technique reduced TBARS levels in blood and intestinal tissue and promoted the maintenance of antioxidant defense in mesenteric acute injury.

Resumo em Inglês:

ABSTRACT Purpose: The protective effect of silibinin on kidney and lung parenchyma during hepatic ischemia/reperfusion injury (IRI) is explored. Methods: Sixty-three Wistar rats were separated into three groups: sham; control (45 min IRI); and silibinin (200 μL silibinin administration after 45 min of ischemia and before reperfusion). Immunohistochemistry and real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) were used to evaluate the expression levels of MMP2, MMP3, MMP9, and TIMP2 on kidney and lung. Results: Comparing sham vs. control groups, confirmed that hepatic IRI increased both renal and lung MMP2, MMP3, MMP9 and TIMP2 expressions starting at 180 min (p<0.001). Comparison of the control vs. silibinin groups showed a statistically significant decrease in the expression levels of MMP2, MMP3, and MMP9 and increase of TIMP2 in kidney and lung parenchyma. The starting point of this decrease was at 120 min after reperfusion, both for kidney and lung parameters, and it was statistically significant at 240 min (p<0.001) for kidney, while silibinin showed a peak of lung protection at 180 min after hepatic reperfusion (p<0.001). Conclusions: Hepatic IRI causes distant kidney and lung damage, while a statistically significant protective action, both on kidney and lung parenchyma, is conveyed by the intravenous administration of silibinin.

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ABSTRACT Purpose: To evaluate the morphological, biochemical, and histological effects of aqueous extracts of peanut (skinless and added to 1% skin) in Swiss mice submitted to a high-fat diet. Methods: Forty male Swiss mice were divided into four groups (n=10 per group): GI) normocaloric diet; GII) high-fat diet; GIII) high-fat diet + 0.5 mL of peanut extract; GIV) high-fat diet + 0.5 mL of peanut extract + 1% peanut skin. The animals were weighed weekly and euthanized after 12 weeks for histopathological and biochemical analyses. The study was approved by the Animal Use Ethics Committee. Results: The animals in the GIV group had higher body weight when compared to the other ones. Increase in total cholesterol in GIII, increase in blood glucose in groups GII, GIII and GIV, decrease in serum low-density lipoprotein (LDL) concentration in groups GI and GIV and increase in serum concentration of C-reactive protein in GII were seen. The presence of vacuolar fat deposits was found in animal livers from GII. Conclusions: The extracts improved the plasma concentrations of animals that received a high-fat diet, including preventing morphological damage to liver tissue. These benefits were enhanced by the association of peanut shells with the extract.

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ABSTRACT Purpose: To evaluate the effect of hyperbaric oxygenation (HBO) on angiogenesis in random rat skin flaps, by immunoexpression of vascular endothelial growth factor A (VEGF-A). Methods: Forty adult rats were divided into four groups: GE) epilated; GE/HBO) epilated subjected to HBO; GER) epilated submitted to dorsal skin flap; GER/HBO) epilated subjected to dorsal skin flap + HBO. HBO was performed with rats inside a chamber under atmosphere close to 100% oxygen and pressure of 2.4 absolute atmospheres, 2h per day during seven consecutive days. GE and GER groups were placed in the hyperbaric chamber without HBO. Then, under anesthesia, skin flaps were removed and separated into three portions relative to pedicle fixation. The samples were fixed in formalin and processed for paraffin embedding. Histological sections were submitted to immunohistochemistry for VEGF-A detection. The number of immunostained-blood vessels were counted under light microscopy. Results: GE and GE/HBO groups showed normal and similar skin morphology in the three flap portions. A fibrin-leukocyte crust, along with denatured collagen and intense leukocyte infiltrate, was mainly observed in the dermis of the medial and distal flap portions of GER group. Meanwhile, the GER/HBO group presented more regions with intact collagen and small areas of leukocyte infiltrate in the three flap regions. VEGF-A-immunostained blood vessels were largely seen in all regions of GE and GE/HBO groups, whereas no significant differences were found between these groups. A decrease in vascularization was noticed in GER and GER/HBO groups, which was more evident in the most distal portion of the flaps. However, the number of VEGF-A-immunostained blood vessels in GER/HBO group was significantly higher when compared to GER group. Conclusions: Hyperbaric oxygenation was associated with increased angiogenesis and improved viability of rat skin flaps.

Resumo em Inglês:

ABSTRACT Purpose: To assess the effects of adipocyte-derived stem cell (ASC)-injection on the survival of surgical flaps under ischemia in diabetic rats. Methods: Diabetes was induced in 30 male Wistar rats using streptozotocin (55 mg/kg). After eight weeks, epigastric flap (EF) surgery was performed. The animals were divided into control (CG), medium-solution (MG), and ASC groups. The outcomes were: the survival area (SA), the survival/total area rate (S/TR), and expression levels (EL) of genes: C5ar1, Icam1, Nos2, Vegf-a. Results: In the ASC group, compared to CG, we observed improved flap SA (CG-420 mm2 vs. ASC-720 mm2; p=0.003) was observed. The S/TR analysis was larger in the ASC group (78%) than the CG (45%). This study showed an increase in the Vegf-a EL in the ASC group (2.3) vs. CG (0.93, p=0.0008). The Nos2 EL increased four-fold in the ASC group compared to CG, and C5ar1 EL decreased almost two-fold in the ASC group vs. the CG (p=0.02). There was no difference among the groups regarding Icam1 EL. Compared to the MG, the ASC group had a bigger flap SA (720 mm2 vs. 301 mm2, respectively), a bigger S/TR (78% vs. 32%, p=0.06, respectively) and increased EL of Vegf-a (2.3 vs. 1.3, respectively). No difference between ASC-group and MG was seen regarding Nos2 (p=0.08) and C5ar1 (p=0.05). Conclusions: This study suggests that ASCs increase the survival of EF under IR in diabetic rats.

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ABSTRACT Purpose: To describe a new anesthetic protocol medullary and nerve roots access and in Rattus norvegicus. Methods: Seventy female Wistar rats (n=70) were used. The animals were randomly divided into two laminectomy groups: cervical (n=40) and thoracic (n=30). In cervical group, a right posterior hemilaminectomy was performed to access the nerve roots. In thoracic group, a laminectomy of the eighth thoracic vertebra was accomplished. Thirty-five rats (20 cervical and 15 thoracic) were submitted to old anesthetic protocol (ketamine 70 mg/kg plus xylazine 10 mg/kg); and the 35 other animals (20 cervical and 15 thoracic) were submitted to a new anesthetic protocol (ketamine 60 mg/kg,xylazine 8 mg/kg and fentanyl 0.03 mg/kg). Results: The time to complete induction was 4.15 ±1.20 minin ketamine, xylazine and fentanyl group, and it was 4.09 ±1.47 min in the ketamine and xylazine group. There was no correlation in the time required to perform the cervical laminectomy in the old anesthetic protocol. In all groups, the animals submitted to the old anesthetic protocol had a higher level of pain on the first and third postoperative days than the animals submitted to the new anesthetic protocol. Conclusions: The new anesthetic protocol reduces the surgical time, allows better maintenance of the anesthetic plan, and brings more satisfactory postoperative recovery.