Effects of tempol, a membrane-permeable radical scavenger, on local and remote organ injuries caused by intestinal ischemia/reperfusion in rats.

BACKGROUND: Tempol is a stable piperidine nitroxide of low molecular weight that permeates biological membranes and scavenges superoxide anions in vitro. In a variety of animal models, deleterious effects of reperfusion injury on both local and remote organs have been demonstrated. In this study, we aimed to investigate the effects of a membrane-permeable radical scavenger, Tempol, on local and remote organ injuries caused by intestinal ischemia/reperfusion (I/R) in rats. MATERIALS AND METHODS: Male Wistar-albino rats were randomized into three groups: (I) Sham-operated control group, laparotomy without I/R injury (n = 12); (II) Intestinal I/R group, 60 min of ischemia by superior mesenteric artery occlusion followed by 2-h of reperfusion (n = 12); and (III) I/R + Tempol-treated group, identical to I/R group except for Tempol administration, 30 mg/kg bolus injection 5 min before reperfusion, followed by an infusion of 30 mg/kg/h intravenously (n = 12). Histopathologically, intestinal mucosal lesions were assessed by Chiu's classification, and pulmonary parenchymal damage was appraised by pulmonary neutrophil infiltration and acute lung injury scaling. Biochemically, myeloperoxidase activity, malondialdehyde, glutathione, and nitrite/nitrate (NO(x)) levels were determined in both intestinal mucosa and lung parenchyma. Evans blue dye concentration and organ wet/dry weight ratios were used as a marker of organ edema. Animal survival was observed up to 1 week. RESULTS: Intestinal mucosal lesions and pulmonary parenchymal damage were significantly attenuated with Tempol treatment, histopathologically (P < 0.05). Tempol administration significantly reduced myeloperoxidase activity and malondialdehyde levels, and also significantly increased glutathione and NO(x) levels of both intestinal and lung tissues, biochemically (P < 0.05). Evans blue dye extravasation and wet/dry weight ratios of organs were significantly reduced with Tempol injection (P < 0.05). The survival rates of rats in Tempol-treated group were significantly higher than that of I/R-treated group (P < 0.05). CONCLUSIONS: The present study suggests that Tempol administration significantly reduces both local and remote organ injuries caused by intestinal I/R before and throughout the reperfusion period. Further clinical studies are needed to clarify whether Tempol may be a useful therapeutic agent to use in particular operations where the reperfusion injury occurs.

Activated protein C prevents deleterious effects of remote reperfusion injury caused by intestinal ischemia on wound healing in the left colonic anastomoses: an experimental study in the murine model.

BACKGROUND: Activated protein C (APC) is a serine protease with anticoagulant and antiinflammatory activities. The delaying effects of remote reperfusion injury on the wound-healing process in colonic anastomoses have been previously shown. In this study, we aimed to investigate whether APC protects against deleterious systemic effects of intestinal ischemia/reperfusion (I/R) injury on colonic anastomotic wound healing process. METHODS: Male Wistar-albino rats were randomly allocated into 4 groups, and a left colonic anastomosis was performed in all animals: (1) sham-operated group, simultaneously with left colonic anastomosis, the superior mesenteric artery and collateral branches were divided from the celiac axis, and the inferior mesenteric artery were isolated but not occluded (group 1, n = 12), (2) sham + APC group, identical to group 1 except for APC treatment (100 microg/kg, intravenously, 15 minutes before construction of the colonic anastomosis), (group 2, n = 12), (3) intestinal I/R group, 60 minutes of superior mesenteric ischemia followed by reperfusion (group 3, n = 12), and (4) APC-treated group, (100 microg/kg, intravenously, 15 minutes before reperfusion) (group 4, n = 12). All animals were sacrificed, and colonic anastomotic bursting pressures were measured in vivo on day 7. Tissue samples were obtained for analysis of hydroxyproline contents, nitrate/nitrite levels, and activities of oxidative and antioxidative enzymes. The plasma levels of proinflammatory cytokines and D-dimer were also measured. RESULTS: Intestinal I/R led to significant decreases in colonic anastomotic bursting pressures, tissue hydroxyproline contents, and activities of antioxidative enzymes, along with increases in tissue nitrate/nitrite levels, activities of oxidative enzymes, and plasma levels of proinflammatory cytokines and D-dimer (P < .05). However, APC treatment led to significant increases in colonic anastomotic bursting pressures, tissue hydroxyproline contents, and activities of antioxidative enzymes, along with decreases in tissue nitrate/nitrite levels, activities of oxidative enzymes, and plasma levels of proinflammatory cytokines and D-dimer (P < .05). CONCLUSION: This study clearly showed that APC treatment prevented the delaying effects of remote I/R injury on colonic anastomotic wound healing process. Further clinical studies are required to determine whether APC has a useful role in the enhancement of colonic anastomotic wound healing after particular operations in which I/R injury occurs.

Activated protein C attenuates intestinal reperfusion-induced acute lung injury: an experimental study in a rat model.

BACKGROUND: Activated protein C (APC) is a serine protease with anticoagulant and anti-inflammatory activities. APC has been shown to attenuate local deleterious effects of ischemia/reperfusion (I/R) injury in many organs. We aimed to investigate the effects of APC on lung reperfusion injury induced by superior mesenteric occlusion. METHODS: Male Wistar-Albino rats were allocated into 4 groups: (1) sham-operated group, laparotomy without I/R injury (n = 12); (2) sham + APC group, identical to group 1 except for APC treatment (n = 12); (3) intestinal I/R group, 60 minutes of ischemia followed by 3 hours of reperfusion (n = 12); and (4) I/R + APC-treated group, 100 microg/kg injection of APC intravenously, 15 minutes before reperfusion (n = 12). Evans blue dye was injected into half of the rats in all groups. We assessed the degree of pulmonary tissue injury by measuring activities of oxidative and antioxidative enzymes, as well as nitrate (NO(3)(-))/nitrite (NO(2)(-)) levels, biochemically. We evaluated acute lung injury (ALI) by establishing pulmonary neutrophil sequestration and ALI scoring histopathologically. Pulmonary edema was estimated by using Evans blue dye extravasation and wet/dry ratios. The plasma levels of proinflammatory cytokines and D-dimer were measured. RESULTS: APC treatment significantly reduced activities of oxidative enzymes and nitrate/nitrite levels in the lung tissues, and plasma levels of proinflammatory cytokines and D-dimer, and also significantly increased activities of antioxidative enzymes (P < .05). Pulmonary neutrophil sequestration and ALI scores were decreased significantly with APC administration (P < .05). In addition, APC treatment significantly alleviated pulmonary edema (P < .05). CONCLUSIONS: This study clearly showed that APC treatment significantly attenuated the lung reperfusion injury. Further clinical studies are required to clarify whether APC has a useful role in the reperfusion injury during particular surgeries in which I/R-induced organ injury occurs.

Role of allopurinol on oxidative stress in caustic burn: cure for stricture?

An experimental study was conducted to investigate the effects of allopurinol, which inhibits the enzyme xanthine oxidase, on oxidative stress and on the prevention of stricture development after esophageal caustic injuries in rat. A randomized controlled study was conducted and 60 Wistar albino rats were divided into 6 equal groups, three groups for the acute phase and 3 groups for the chronic phase. Caustic esophageal burn was created by application of 37.5% NaOH to the distal esophagus. Allopurinol was administered at 40 mg/kg daily. Efficacy of the treatment for the acute phase was assessed by measuring tissue malondialdehyde (MDA), nitric oxide (NO) and glutathione (GSH) at the 3rd day; and for the chronic phase by determining tissue hydroxyproline content and histopathologic damage score at the 28th day. We found an increase in XO, MDA and GSH levels and a decrease in NO levels in the acute phase. Allopurinol reinstated the increase in XO significantly, while MDA, GSH and NO levels were reinstated insignificantly. There was no significant difference in means of tissue hydroxyproline content. Histopathologic damage scores were significantly lower in the allopurinol treated group. This study, which is to our knowledge, the first in the literature investigating the influence of allopurinol on caustic esophageal burn, reveals that allopurinol effects MDA, GSH and NO levels insignificantly in the acute phase of caustic esophageal burn and decreases fibrosis significantly in the chronic phase.

Analysis of zinc and magnesium levels in pinealectomized chicks: roles on development of spinal deformity?

Melatonin is the main product of the pineal gland, and trace metals play a critical role in growth and development. The purpose of this study was to assess the serum zinc (Zn) and magnesium (Mg) levels in pinealectomized chicks and their possible interactions with the development of spinal deformity. Chicks were divided into two equal groups: unoperated controls (group M) and pinealectomized chicks (group N). Pinealectomies were performed at the age of 3 d. After 8 wk, serum Zn and Mg levels of 10 animals from each group were measured by spectrophotometric assay. The results of analyses were compared using the Mann-Whitney U-test. The correlation between serum Zn and Mg levels were assessed by Spearman's correlation. In this study, it was obvious that the serum Zn levels in group N were significantly lower than those in group M (2.8 +/- 0.10 vs 4.2 +/- 0.14 ppm; p < 0.0005). In contrast, Mg levels in group N was high compared with the values in group M, although there was no significant difference (17.8 +/- 0.69 vs 15.7 +/- 0.85 ppm; p > 0.05). In pinealectomized animals, serum Zn levels declined significantly while serum Mg levels increased, albeit insignificantly. Thus, there was a moderately positive but not statistically significant correlation between Mg and Zn levels in unoperated controls (r = 0. 273, p > 0.05), whereas there was a negative but not statistically significant correlation between Zn and Mg levels in pinealectomized chicks (r = -0.115, p > 0.05). In addition, the serum Mg to serum Zn ratio was significantly higher in group N than in the group M control (6. 39 +/- 0.32 vs 3.75 +/- 0.22, respectively; p < 0.001). From the results of the current study, it is clear that surgical pinealectomy in newly hatched Hybro Broiler chicks has a significant effect on serum Zn level. However, the serum Mg did not change significantly. Because serum Mg is not a good indicator of Mg status in chicks, it is speculated that other tissues, such as muscle or spine, might productively be explored as a more sensitive Mg biomarker for this model. The present study provides experimental evidence that serum trace metal levels might be affected in pinealectomized animals because of the lack of its main neurohormone melatonin.

Correlation of serum trace elements and melatonin levels to radiological, biochemical, and histological assessment of degeneration in patients with intervertebral disc herniation.

The aim of our study was to assess the blood concentrations of some trace elements and melatonin (MLT) in patients with intervertebral disc herniation (IDH) and to investigate the interaction of histological and biochemical degeneration findings with aging. The present study was carried out on 13 subjects (8 women and 5 men) diagnosed with IDH. They were divided into three groups according to their ages. Nighttime serum MLT, zinc (Zn), and magnesium (Mg) levels were determined in all patients. In addition, computed tomography (CT) scan of the brain and magnetic resonance imaging examination of the lumbar spine were obtained in this study. The Zn level and Zn/Mg ratio showed a decline in patients with IDH with aging, whereas the serum Mg level and tissue hydroxyproline content increased. A positive correlation between serum Zn and MLT concentrations was found (r=0.104, p=0.734). In addition, there was a positive correlation between serum Zn level and Zn/Mg ratio (r=0.835 and p<0.01), and a negative correlation between serum Mg level and Zn/Mg ratio (r=-0.571, p<0.05). On CT study, both volume percentage of calcified pineal gland and density of calcification were found to increase progressively with advancing age. The results of semiquantitative evaluation of disc tissues of patients with IDH for histological degeneration findings showed that 66.7% of discs treated had slight degeneration in younger age group, but 75.0% and 100% of discs had moderate or marked degeneration in older age groups. Our data indicated that there is a close relationship between MLT and Zn or Mg levels in the serum samples of patients with IDH, and the levels of these elements might be affected by the presence of degeneration process and serum MLT level, or vice versa.