Leukocyte activation, oxidant stress and red blood cell properties after acute, exhausting exercise in rats

Red blood cell (RBC) mechanical alterations and oxidative damage were investigated after an acute exhausting exercise in rats, together with the leukocyte activation. The groups formed as follows. Control (C) (n = 9), group I (n = 9) and group II (n = 7) from which blood samples were collected 15 minutes and 24 hours respectively, after acute exercise. The rats were subjected to running at a speed of 17 m/min until exhaustion. The leukocyte phagocytic activity (LPA), RBC lipid peroxidation and RBC deformability were measured. LPA increased significantly after the exhausting exercise and prolonged till 24 hours (p = 0.0168). RBC membrane lipid peroxidation was gradually increased till 24 hours (p = 0.0297) and there was a significant correlation between LPA and RBC lipid peroxidation (r = 0.63, p = 0.015). There was a slight but significant decrease in mean corpuscular volume (MCV) (p = 0.0467) and increase in mean corpuscular hemoglobin concentration (MCHC) (p = 0.0458) suggesting a cellular dehydration after 24 hours. No significant alteration was detected in RBC deformability, assessed by the Cell Transit Analyzer (CTA) and thought that decreased MCV might have masked to determine the alterations in membrane mechanical properties in CTA. As a conclusion the results imply that activated leukocytes might play role in the RBC damage observed after exhausting exercise encouraging oxidative stress.

Lipid peroxidation and antioxidant enzyme levels of intestinal renal and muscle tissues after a 60 minutes exercise in trained mice

To investigate the effect of blood perfusion difference on oxidant status, mice were trained by a 7-week running program. Two days after the last training session, mice were exercised for 60 minutes at the same training intensity. Changes in the concentration of thiobarbituric acid reactive substance (TBARS), as an index of lipid peroxidation, in intestine, kidney and muscle, were studied in trained mice immediately (0 h), 3 h and 24 h after the running exercise and in unexercised control group. The activities of superoxide dismutase (SOD), glutathione peroxidase (GPx) and xanthine oxidase (XO) were determined in these tissues. Tissue SOD activities were unaffected by the exercise. Muscle GPx activity increased after exercise (0 h and 3 h group, P < 0.01) and returned to control levels at 24 h, but there was not any significant difference in intestinal and renal tissues. Renal tissue XO activity could not be determined. There was not any significant difference among groups in intestinal tissue XO activity. The activity of XO was decreased only in skeletal muscle at 0 h (P < 0.05). TBARS levels of exercised groups were higher than control in muscle (P < 0.01). Intestinal TBARS levels decreased at 0 h (P < 0.05), than reached to control level. Renal TBARS levels of 0 h and 24 h group was higher than control (P < 0.01, P < 0.01 respectively). The results show that a long distance running exercise may cause lipid peroxidation damage in skeletal muscle and kidney.

The effects of single dose of methamphetamine on lipid peroxidation levels in the rat striatum and prefrontal cortex

The administration of methamphetamine to experimental animals results in damage to dopaminergic neurons. In the present study, we demonstrated that a single dose (15 mg/kg) of methamphetamine results in production of oxidative stress as demonstrated by increased thiobarbituric acid reactive substances levels in the rat striatum and prefrontal cortex. In conclusion, the results of present study provide further evidence in support of the notion that oxidative stress may play an important role in the methamphetamine-induced neurotoxicity.

Effects of prenatal ethanol exposure on neuronal migration, neuronogenesis and brain myelination in the mice brain

BACKGROUND

One of the most severe consequences of maternal alcohol consumption is the damage to the developing central nervous system.

MATERIAL AND METHODS

To evaluate the effect of prenatal alcohol exposure on neuronal migration, neuronogenesis and myelination in the brain, pregnant BALB/C mice were maintained on either liquid diets containing ethanol (12 g/kg body weight) beginning on gestation day 6 or isocoloric diet (control group). The dams were sacrificed on gestation day 17 and the brain sections of the pups were analyzed using immunohistochemical method to evaluate the number of neurons, oligodendrioglial expression of myelin basic protein (MBP) and neuronal expression of neural cell adhesion molecule (NCAM).

RESULTS

Ethanol-exposed pups revealed significantly weaker expression of MBP compared to the control group. In contrast, no significant difference of NCAM expression and neuronal cell count were present between ethanol-exposed pups and the control group.

CONCLUSION

These data demonstrate that alcohol exposure affects the level of MBP expression, consequently causing a reduction in brain myelination that may lead to neuronal dysfunction. The ineffectiveness of prenatal alcohol exposure on the number of neurons in contrast to the previous reports might be due to the adequate sampling of areas for cell counting. Although there is a view that NCAM is involved both directly and indirectly in neuronal cell migration, we speculate that alcohol neuroembryotoxicity uncouples this relationship. Other adhesion molecules, such as L1, or extracellular matrix proteins, such as laminin, would be other candidates for investigation.

The effect of skin transplantation on tumor growth in mice

BACKGROUND

Skin allograft is an immunostimulant. Skin allograft activates effector arms of the immune system including the cytotoxic T lymphocytes, activated macrophages, and natural killer cells. These cells may be involved in the destruction of tumor cells.

METHODS

Balb/c mice were divided into the study (n = 10) and control (n = 10) groups. Alloskin grafts 1 cm in diameter from the backs of Swiss albino mice were placed on the backs of balb/c mice (study group). The same size autoskin grafts from the backs of other balb/c mice were used for the control group. Fourteen days after grafting, we inoculated 1,000 Ehrlich ascites tumor cells intraperitoneally into both groups. Two days after tumor inoculation, we used secondary allografts and autografts (which were about 2 to 3 mm in diameter) for the same groups. We followed up graft survival and animal survival in both groups.

RESULTS

All 10 of the autografted mice died between the 18th and 25th days owing to malignancy. In the allografted group, 2 mice died (1 on day 17 and the other on day 23). Allograft rejection had not occurred in these 2 mice at the time of their death. The other 8 mice in the same group rejected allograft, on average within 9 days (9+/-3, median 8). These 8 mice were alive and without apparent health problems during the 4 months of follow-up.

CONCLUSION

Allo-skin graft rejection may help rejection of tumor cells and may be of use in immunotherapy of cancer.

The role of vitamin A in preventing renal scarring secondary to pyelonephritis

OBJECTIVE

To evaluate the efficiency of exogenously administered vitamin A in preventing renal scarring caused by experimental pyelonephritis in rats.

MATERIALS AND METHODS

Forty Wistar rats were injected with 0.1 mL of solution containing Escherichia coli (1010 /mL) into both renal medullae. Five equal groups were then formed: group 1 was treated only with ciprofloxacin (30 mg/kg per day, twice daily, intraperitoneally) for 5 days, starting 3 days after bacterial inoculation; in group 2, 60 kIU of vitamin A was injected intramuscularly with the bacterial inoculation; in group 3, 60 kIU of vitamin A was injected similarly, but 3 days after bacterial inoculation; in group 4, 60 kIU of vitamin A was given orally with the bacterial inoculation; and group 5 was treated with ciprofloxacin for 5 days and vitamin A intramuscularly from the third day after bacterial inoculation. All the rats were killed 6 weeks after bacterial injection; blood samples were obtained to determine serum vitamin A and beta-carotene levels, and both kidneys were examined pathologically for scarring, graded as 0 (none), 1 (mild), 2 (moderate) and 3 (severe).

RESULTS

Serum vitamin A levels were higher in the rats given vitamin A (group 2-5) than in group 1, being highest in group 4, although only this group had significantly higher levels of vitamin A than group 1 (P<0.05). Histopathologically, the fibrosis was mildest in groups 2 and 4 (two of 16 kidneys grade 1), whereas it was most severe in group 1 (all 16 grade 2-3). Fibrosis was significantly less in groups 2-5 than in group 1 (P<0.05). There was a significant negative correlation between vitamin A levels and the sum of the fibrosis, inflammation and tubular atrophy scores of all rats (r=-0.391, P<0.02). beta-carotene levels were unrelated to renal scarring.

CONCLUSION

The administration of vitamin A could have a role in preventing renal scar formation from pyelonephritis induced experimentally in rats.

Methamphetamine causes lipid peroxidation and an increase in superoxide dismutase activity in the rat striatum

The administration of methamphetamine to experimental animals results in damage to nigrostriatal dopaminergic neurons. In the present study, we demonstrated that both the acute repeated and the chronic administration of methamphetamine causes an increase in thiobarbituric acid reactive substances, which are indicators of lipid peroxidation, and superoxide dismutase activity in the rat striatum. The results of present study strengthen the notion that reactive oxygen species may play an important role in the methamphetamine-induced neurotoxicity.

Circadian rhythmicity in serotonin-induced acute gastric mucosal injury in rats

Time-dependent patterns in the susceptibility of the rat gastric mucosa to ulcerogenic stimuli involving stress or chemical injury have been described. The purpose of this study was to evaluate whether serotonin (5-HT)-induced gastric mucosal injury is produced in a circadian fashion in the rat model. In fasted Wistar rats (adapted for 3 weeks to a standard 12-h light-dark cycle), 5-HT administered subcutaneously (20 mg/kg, 4 h before autopsy) produced gastric mucosal injury. The stomachs were removed and the ulcers were scored for intensity, using a scale of 0-4. In studies performed at 4-h intervals, beginning 1 h after lights-on, most of the mucosal injury occurred at 2000 h, i.e. early in the dark phase. Likewise, serum corticosterone levels were also found to be high at the same time period. The time of 2000 h is approximately determined to be the beginning of the rats' active period. These results suggest that the extent of acute 5-HT-induced gastric mucosal injury varies with the time of day and that elevations in corticosterone concentrations might be responsible for the 5-HT-induced gastric mucosal injury.

IgA nephropathy in mice following repeated administration of conjugated Haemophilus influenzae type B vaccine (PRP-T)

OBJECTIVE

In this study, the risk of IgA nephropathy in Swiss albino mice following the subcutaneous administration of conjugated Haemophilus influenzae type b vaccine (PRP-T), containing capsular polysaccharide of the organism (PRP) conjugated to tetanus protein (T), was evaluated.

METHODS

Three treatment and corresponding control groups, each containing mice, were constituted and given 2, 4, 6 injections of 1/4 HD of PRP-T or placebo, respectively, at 2-week intervals. All mice in each treatment group were sacrificed two weeks from the last injection to examine sequential glomerular changes.

RESULTS

The niceoscpic examination of renal tissues revealed mesangial proliferation (6/7; 85%) in the first group given 2 doses of vaccine; mesangial proliferation (5/7; 72%) and increase in matrix (7/7; 100%) in the second group given 4 doses; and mesangial proliferation (7/7; 100%), increase in matrix (7/7; 100%), IgA (7/7; 100%) and C3 (3/7; 42%) deposition within mesangium in the third group given 6 doses. No histopathological changes were detected in the renal tissues of any control mouse. When the experimental groups were compared statistically with their respective controls at the light microscopic level, mesangial proliferation in the first group (p: 0.0047), mesangial proliferation (p: 0.021) and increase in matrix (p: 0.001) in the second group, mesengial proliferation (p: 0.001) and increase in matrix (p: 0.001) in the third group were determined to be significantly different. When study and control groups were compared by immunofluorescence microscopy, only the third group revealed a statistically significant difference with respect to IgA deposition (p: 0.001). C3 deposition was also demonstrated in this group, but it was not significantly different (p: 0.192). However, in no instance was a control mouse found to have any form of immune deposition.

CONCLUSION

We concluded that conjugated Haemophilus influenzae type b vaccine, given at two-week intervals to a total of six doses, caused secondary IgA nephropathy in mice.

Urinary N-acetyl-beta-D-glucosaminidase activity in rabbits with experimental hypercalciuria

Routinely used renal function tests remain normal in uncomplicated hypercalciuria. The aim of this study was to assess the value of N-acetyl-beta-D-glucosaminidase (NAG), a sensitive marker of renal proximal tubular damage, in experimental hypercalciuria. Oral calcium providing 75 mg/kg per day elementary calcium and 20,000 IU/day vitamin D3 was administered for 15 days to 7 rabbits (Orytolagus cuniculus-New Zealand white) and 7 rabbits were given placebo as a control group. Serum calcium, phosphorus, and alkaline phosphatase, daily urinary calcium excretion and NAG/creatinine ratio were measured before and after drug administration. Kidneys were examined macroscopically and microscopically following the study period. Serum calcium, phosphorous and urinary calcium excretion increased, while alkaline phosphatase decreased significantly in response to drug treatment [10.8 +/- 1.5 vs. 12.2 +/- 1.3 mg/dl, 4.6 +/- 0.6 vs. 6.7 +/- 0.7 mg/ dl, 22.3 +/- 8.3 vs. 46.8 +/- 22.5 mg/kg per day, and 138.0 +/- 57.1 vs. 70.1 +/- 33.1 IU/l, respectively (P < 0.05)]. The NAG/creatinine ratio prior to the study (0.5 +/- 0.1 mU/ mg) was significantly different from that after the study (5.4 +/- 1.5 mU/mg, P < 0.01). In the control group, changes in serum and urinary parameters were not significant (P > 0.05). The relationship between the urinary NAG/ creatinine ratio and the daily urinary calcium excretion was statistically significant (r = 0.67, P < 0.05). In the study group, nephrocalcinosis was present in all rabbits except 1 (85.7%), whereas none of the control group rabbits had nephrocalcinosis. In conclusion, in rabbits urinary NAG excretion increases significantly in nephrocalcinosis induced by hypercalciuria.

Ureaplasma urealyticum-induced urinary tract stones in rats

This study investigated the possible role of Ureaplasma urealyticum, which is predominantly located in the urogenital tract, in the formation of infectious stones. A standardized Ureaplasma urealyticum broth culture isolated from a human urogenital specimen was inoculated into the renal medulla of five male rats (Rattus norvegicus L., Wistar C, weighing 170 +/- 10 g) and the same amount of culture media was used for five identical control rats. Five days after the inoculation, the rats were killed and fresh preparations from the bladders and the inoculated kidneys of both groups were prepared. At the same time biochemical and histopathological analysis of the contents of the bladders and the inoculated kidneys of both groups was performed. Crystal formation within the bladders of the inoculated rats was demonstrated and biochemical analysis of the crystals showed calcium, magnesium and phosphate, which indicated the existence of infection-induced crystals. These findings were absent in the control rats. The role of Ureaplasma in the production of urinary tract infectious stones was thus demonstrated in vivo.

The effect of acute bilateral adrenalectomy on serotonin-induced inhibition of gastric acid secretion and acute gastric mucosal injury in rats

Serotonin (5-hydroxytryptamine, 5-HT) produces many changes in gastric functional parameters, including the inhibition of gastric acid secretion and changes in mucosal blood flow. Exogenous 5-HT has also been shown to induce gastric erosion. The influence of adrenalectomy on experimental lesions in the rat gastric mucosa remains controversial. The aim of this study was to see the effects of adrenalectomy on pentagastrin stimulated gastric acid secretion in anaesthetized male Wistar rats. Gastric acid was collected via cannulae placed in the stomach. 5-HT (3.5 mumol/kg, i.v.) inhibited pentagastrin stimulated acid output by 54% and produced haemorrhagic gastric lesions with a mean ulcer index of 2 +/- 0.3. Adrenalectomy prevented both 5-HT induced inhibition of gastric acid secretion and mucosal injury. The results suggest that the effects of 5-HT require an intact adrenal gland.

Lung clearance of aerosolized 99mTc erythromycin lactobionate in rabbits

In order to assess the lung clearance of aerosolized 99mTc Erythromycin Lactobionate (EL), 99mTc EL was administered to 9 New Zealand rabbits by inhalation. 5 rabbits inhaled cigarette smoke before 99mTc EL. Clearance half times were 3.0 +/- 0.9 hours in normals, 5.5 +/- 1.0 hours after smoke exposure. Clearance was not affected after destroying the surfactant layer. Slower clearance after smoke exposure may be due to the inhibition of mucociliary clearance. 99mTc EL can be considered as an alternative radioaerosol for ventilation imaging.

The effect of extracorporeal electromagnetic shock waves on the morphology and contractility of rabbit ureter

PURPOSE

Although extracorporeal shock wave lithotripsy (ESWL) is known to cause pathologic changes in various organs, little is known about its effects on the ureter, the target organ in ESWL of ureteral stones in situ. In this study, we sought to determine the short-term effects of ESWL on the ureter.

MATERIALS AND METHODS

Left lower ureteral segments of 21 rabbits were removed to serve as the control group and 2000 shocks were applied to the right lower ureters. Groups of 7 rabbits were sacrificed 1, 3 and 5 days after shock wave exposure. While histomorphological alterations were examined under light and transmission electron microscopy, contractility of all ureters was determined in organ baths.

RESULTS

The epithelial cells disclosed no change after shock wave application. Histologically the muscular layer was the most affected part of the ureter. There was interstitial and intracellular edema on light microscopy and marked chromatin and mitochondrial changes at the subcellular level. The adventitial layer was also edematous. These changes were prominent on days 1 and 3 and returned to normal on day 5. The contractility of the ureters on day 1 was significantly reduced (p < 0.05). However, the contractility of the samples on days 3 and 5 were not significantly different from controls.

CONCLUSION

Our findings demonstrate that electromagnetic shock waves produce reversible morphological and functional changes in rabbit ureteric muscle.

Serotonin causes acute gastric mucosal injury in rats, probably via 5HT1D receptors

5-HT-induced acute gastric mucosal injury was assessed in rats by using 5HT1, 5HT2, 5HT3, 5HT4 or muscarinic receptor related drugs. Rats were treated with antagonists i.p. and 30 minutes later either vehicle, 5-HT (20 mg/kg) or other agonists were administered s.c. The stomachs were removed 4 hours after the last injection and mucosal integrity was assessed by light microscopy using a histological ulcer index (HUI). The HUI was found to be significantly increased following 5-HT administration (1.57 +/- 0.3) when compared with controls (0.14 +/- 0.1). 5HT1 agonist 5-carboxamidotryptamine (20 mg/kg) produced acute gastric erosion and increased the HUI (P < 0.05). The HUI in the animals receiving 5-HT1D agonist sumatriptan (7 mg/kg) was found to be 1.62 +/- 0.24. 5HT2 antagonist ketanserine (2.5-15 mg/kg), 5HT3 antagonist ondansetron (1-5 mg/kg), 5HT4 antagonist DAU 6285 (1-10 mg/kg) and atropine (1.5-30 mg/kg) exerted no effect whereas 5HT1/2 antagonist metitepine (0.05-0.5 mg/kg) caused a dose dependent inhibition of the effect of 5-HT. The results from this study demonstrate that 5-HT causes acute gastric mucosal injury and this injury is probably due to the activation of the 5-HT1D receptors.