Resumo em Inglês:Abstract Purpose: To investigate the potential protective effects of erdosteine against the harmful effects of ischemia-reperfusion injury on the liver in an experimental rat model. Methods: Forty rats were divided into 4 groups. In the sham group, only the hepatic pedicle was mobilized. No other manipulation or treatment was performed. In the other groups, ischemia was achieved by clamping the hepatic pedicle for 60 min. After that, 90 min reperfusion was provided. In the control group, no treatment was given. In the perioperative treatment group, 100 mg/kg erdosteine was administered 2 hours before ischemia induction. In the preoperative treatment group, 100 mg/kg/day erdosteine was administered daily for ten days before the operation. At the end of the procedures, blood and liver samples were obtained for biochemical and histopathological assessment. Results: Treatment with erdosteine ameliorated the histopathological abnormalities when compared with the control group. Furthermore, this treatment significantly decreased the serum liver function test values. It was also found that erdosteine ameliorated the oxidative stress parameters in both the perioperative and preoperative treatment groups. Conclusion: The current study is the first to have shown the favorable effects of erdosteine on the harmful effects of experimental hepatic ischemia-reperfusion injury.
Resumo em Inglês:Abstract Purpose: To analyze the effects of aging in rats on the nuclear volume, cytoplasmic volume, and total volume of Leydig cells, as well as their number. Methods: Seventy-two Wistar rats were divided into six subgroups of 12 rats, which underwent right orchiectomy at 3, 6, 9, 12, 18, and 24 months of age. The weight and volume of the resected testicles were assessed. A stereological study of Leydig cells was conducted, which included measurements of cell number and nuclear, cytoplasmic, and total cell volumes. Results: The weight and volume of the resected testicles showed reductions with age. Only the subgroup composed of 24-month old rats showed a decrease in the nuclear volume of Leydig cells. Significant reductions in the cytoplasmic volume and total volume of Leydig cells were observed in 18- and 24-month old rats. The number of Leydig cells did not vary significantly with age. Conclusions: Aging in rats resulted in reduction of the nuclear, cytoplasmic, and total cell volumes of Leydig cells. There was no change in the total number of these cells during aging.
Resumo em Inglês:Abstract Purpose: Topical hypothermia and local ischemic preconditioning have been shown to reduce renal ischemia-reperfusion (I/R) injury individually. We examined whether combination of both strategies lessens renal I/R injury. Methods: Post right nephrectomy, 40 male Wistar rats were randomly assigned to five experimental protocols performed in the left kidney: topical hypothermia without ischemia (TH), warm ischemia (IR), ischemic preconditioning followed by warm ischemia (IPC+IR), cold ischemia (TH+IR), and ischemic preconditioning followed by cold ischemia (IPC+TH+IR). Eight randomly assigned right kidneys constituted the control group. After 240 min of reperfusion, the left kidney was retrieved to evaluate histological changes, lipid peroxidation and antioxidant enzymes activity. Serum was collected to evaluate urea and creatinine. Results: IPC+TH+IR group revealed no difference to any other group subjected to ischemia in relation to histological changes, lipid peroxidation and antioxidant enzymes activity. Creatinine was lower in IPC+TH+IR group compared with IPC+IR, but showed no difference compared to TH+IR group. Conclusions: Combination of local ischemic preconditioning (IPC) and topical hypothermia conferred no protection in renal I/R injury. Moreover, local IPC solely followed by warm ischemia impaired renal function more than warm ischemia alone.
Resumo em Inglês:Abstract Purpose: To evaluate the use of platelet-rich plasma in the early stages of healing of traumatic injury of the medial collateral ligament in the knee of rabbits. Methods: Thirty rabbits were subjected to surgical lesion of the medial collateral ligament. Of these, 16 were treated with platelet-rich plasma and 14 with saline (control). After 3 and 6 weeks of treatment, 50% of the animals from each group were sacrificed, and biomechanical tests were performed on the injured ligament to compare the tensile strength between the two groups. Results: Platelet-rich plasma significantly increased the tensile strength of the ligament in the groups treated after3 and 6 weeks. In the group treated with platelet-rich plasma vs. saline, the tensile strength values were 3192.5 ± 189.7 g/f vs. 2851.1 ± 193.1 g/f at3 weeks (p = 0.005) and 5915.6 ± 832.0 g/f vs. 4187.6 ± 512.9 g/f at 6 weeks (p = 0.0001). Conclusion: The use of platelet-rich plasma at the injury site accelerated ligament healing in an animal model, demonstrated by an increase in the tensile strength of the medial collateral ligament.
Resumo em Inglês:Abstract Purpose: To present an alternative experimental model of third degree burn of easy reproducibility. Methods: Eighteen male Wister rats were randomly divided into three groups, 6 of which were allocated to each group. A soldering iron coupled to an aluminum plate was used to produce burn, at a temperature of 150ºC, with different exposure times per group. Group 5 (G5) animals were burned at 150°C with exposure time of 5 seconds; Group 10 (G10) the animals were burned at 150°C with exposure time of 10 seconds and group 15 (G15) the animals were burned at 150°C with exposure time of 15 seconds. Results: Histopathological analyzes showed that all three groups had similar morphological characteristics, with total thickness involvement. Conclusion: The technique is effective to reproduce a third degree burn and suggests the temperature of 150ºC with 5 seconds of exposure in order to minimize the risks to the animals.
Resumo em Inglês:Abstract Purpose: To evaluate the bone structure of the mandibular condyle through an animal model, after ovariectomy. Methods: Thirty-six female Wistar rats were divided into 2 groups. The OVX group was submitted to bilateral ovariectomy, the SHAM group underwent the same surgical treatment, but without removal of the ovaries. After 90, 105 and 135 days after surgery, six animals from each group were submitted to euthanasia and the part containing the condyle was removed. Results: The microscopic analysis shows an increase in marrow spaces over time in the OVX group. The morphometric study shows reduction in the amount of bone tissue in the OVX group 135 days period in comparison with for the initial period (90 days) (p <0.05, ANOVA, Tukey). Conclusion: The estrogen deficiency also affects the bone structure of the condyle.
Resumo em Inglês:Abstract Purpose: To evaluate the preventive effect of ascorbic acid on sevoflurane-induced acute renal failure in an experimental rat model. Methods: Twenty-four adult male Wistar rats were randomly distributed into three groups. Subjects were allocated into 3 groups: Group I received sevoflurane only, whereas Groups II and III had moderate (150 mg/kg) and high (300 mg/kg) doses of AA in addition to sevoflurane, respectively. Rhabdomyolysis and myohemoglobinuric ARF was formed by intramuscular administration of glycerol on the upper hind limb on the 15th minute of inhalation anesthesia. Biochemical parameters consisted of serum levels of blood urea nitrogen, creatinine, neutrophil gelatinase-associated lipocalin (NGAL), total antioxidant capacity (TAC), and protein carbonyl content. Histopathological variables were tubular necrosis, fibrin, and cast formation. Results: NGAL levels were significantly lower in Group III than Group II and Group I. On the other hand, TAC, PCO, urea and creatinine levels were notably higher in Group I compared with Groups II and III. There was a significant difference between 3 groups on frequencies of acute tubular necrosis (p=0.003), fibrin (p<0.001) and cast (p<0.001). Acute tubular necrosis and fibrin formation were more prominent in Group I. Casts were more common in Groups II and III. Conclusions: The ascorbic acid serve as a prophylactic agent against renal damage in patients receiving sevoflurane anesthesia and higher doses were associated with more apparent protective effects.
Resumo em Inglês:Abstract Purpose: To investigate whether the neuroprotective effect of TSA on cerebral ischemia reperfusion injury is mediated by the activation of Akt/GSK-3β signaling pathway. Methods: Mice were randomly divided into four groups (n=15): sham group (S); ischemia reperfusion group (IR); ischemia reperfusion and pretreated with TSA group (IR+T); ischemia reperfusion and pretreated with TSA and LY294002 group (IR+T+L). The model of cerebral ischemia reperfusion was established by 1h of MCAO following 24h of reperfusion. TSA (5mg/kg) was intraperitoneally given for 3 days before MCAO, Akt inhibitor, LY294002 (15 nmol/kg) was injected by tail vein 30 min before the MCAO. Results: TSA significantly increased the expression of p-Akt, p-GSK-3β proteins and the levels of SOD, Bcl-2, reduced the infarct volume and the levels of MDA, ROS, TNF-α, IL-1β, Bax, Caspase-3, TUNEL and attenuated neurological deficit in mice with transient MCAO, LY294002 weakened such effect of TSA dramatically. Conclusions: TSA could significantly decrease the neurological deficit and reduce the cerebral infarct volume, oxidative stress, inflammation, as well as apoptosis during cerebral ischemia reperfusion injury, which was achieved by activation of the Akt/GSK-3β signaling pathway.
Resumo em Inglês:Abstract Purpose: To evaluate the ability of dexamethasone to protect against cisplatin (CDDP)-induced ototoxicity. Methods: Male Wistar rats were divided into the following three groups: 1) Control (C): 6 animals received intraperitoneal (IP) saline solution, 8 ml/kg/day for four days; 2) C + CDDP: 11 animals received 8 ml/kg/day of IP saline and, 90 min after saline administration, 8 mg/kg/day of IP CDDP for four days; and 3) DEXA15 + CDDP: 11 animals received IP dexamethasone 15 mg/kg/day and, 90 min after dexamethasone administration, received 8 mg/kg/day of IP CDDP for four days. Results: It was found that dexamethasone did not protect against weight loss in CDDP-exposed animals. The mortality rate was comparable with that previously reported in the literature. The auditory threshold of animals in the DEXA15 + CDDP group was not significantly altered after exposure to CDDP. The stria vascularis of animals in the DEXA15 + CDDP group was partially preserved after CDDP exposure. Conclusions: Dexamethasone at the dose of 15 mg/kg/day partially protected against CDDP-induced ototoxicity, based on functional evaluation by brainstem evoked response audiontry (BERA) and morphological evaluation by optical microscopy. However, dexamethasone did not protect against systemic toxicity.
Resumo em Inglês:Abstract Purpose: To evaluate respiratory muscle strength (PImax and PEmax) before and 24 and 48 h after conventional and single-port laparoscopic cholecystectomy. Methods: Forty women with symptomatic cholelithiasis (18 to 70 years) participated in the study. The patients were divided into two groups: 21 patients undergoing conventional laparoscopic cholecystectomy and 19 patients undergoing single-port laparoscopic cholecystectomy. Differences were considered to be significant when p<0.05. Results: The results showed a greater decline in PImax after 24 h in the group submitted to conventional laparoscopic cholecystectomy, with a significant difference between groups (p=0.0308). Conclusion: Recovery of the parameters studied was more satisfactory and respiratory muscle strength was less compromised in the group submitted to single-port laparoscopic cholecystectomy.