N-Nitrosomorpholine-induced oncocytic transformation in rat endocrine organs.

BACKGROUND: N-Nitrosomorpholine (NMO) is one of the most common N-nitroso compounds. An oncocytic transformation has been demonstrated in renal tubules of NMO-treated rats. In our study, we aimed to investigate the potential transformation of oncocytic cells in 6 endocrine organs, i.e., thyroid, adrenal and pituitary glands, pancreas, testis, and bone, of NMO-exposed rats. METHODS: Thirty male rats were born and raised. Fifteen of them were given a single dose of 320 mg NMO per kg body weight, dissolved in drinking water, by a gavage tube. At the end of 52 weeks, the animals in both series were killed. Right after the killing, 6 different endocrine organs (hypophysis, thyroid, pancreas, adrenal gland, bone [femur], and testicles) of each animal were excised. RESULTS: There was no evidence of oncocytic cell development in the control group. In contrast, oncocytes were observed in 8 out of 13 NMO-treated rats: 2 in the adrenal sections, 1 in the thyroid sections, 3 in the pituitary sections, and 2 in the pancreas sections. Thesticle and bone sections were completely normal. CONCLUSIONS: We showed that NMO induced an oncocytic change in pancreas, thyroid, pituitary, and adrenal glands. To date, no identified specific environmental risk factors that lead to an oncocytic transformation in endocrine glands have been reported previously. Given the increasing prevalence of endocrine-disrupting chemicals in the environment, personal care products, manufactured goods, and food sources, there is a need to advance our understanding of the pathological mechanisms underlying oncocytosis in endocrine organs.

Propolis prevents vascular endothelial dysfunction by attenuating inflammation and oxidative damage in the chronic unpredictable stress model of depression in rats.

OBJECTIVES: Chronic stress may lead to depression and vascular endothelial dysfunction. We aimed to evaluate the effects of propolis on vascular functions and the possible mechanisms of its vascular effects in the rat model of chronic unpredictable mild stress (CUMS)-induced depression. METHODS: Male Wistar rats were divided into control, stress (exposure to CUMS), control+propolis and stress+propolis groups (n = 8/each group). CUMS model was induced by exposing rats to various mild stressors daily for 5 weeks. The extract of propolis (100 mg/kg/day) was administered orally to propolis-treated groups for 5 weeks. The depression-like behaviours were assessed with the forced swimming test (FST). Chronic stress resulted in increased immobility response in FST and elevated serum corticosterone levels. Thoracic endothelial functions and expressions of endothelial nitric oxide synthase (eNOS), tumor necrosis factor-alpha (TNFα), interleukin-1beta (IL-1ß), Heme oxygenase-1 (HO-1) and superoxide dismutase (SOD) level were assessed. KEY FINDINGS: Compared to control group, stress group exhibited a significant decrease in endothelium-dependent relaxations, and eNOS, SOD and HO-1 expressions, whereas a significant increase in the thoracic expressions of TNFα and IL-1ß. Propolis ameliorated depression-like behaviours, vascular endothelial dysfunctions and alterations of protein expressions. CONCLUSION: Propolis exerted antidepressant-like and vasculoprotective effects in CUMS-induced depression in rats. Chronic propolis treatment may have a protective effect on CUMS-induced vascular endothelial dysfunction by its anti-inflammatory and antioxidant effects.

Effect of nitric oxide synthase inhibitors in acute lung injury due to blunt lung trauma in rats.

BACKGROUND: This study aims to investigate the effects of blunt lung trauma performed in experimental rat model on lung tissue and blood as well as proinflammatory cytokines, oxidant-antioxidant enzymes and histopathological parameters after Ngamma-nitro-L-arginine methyl ester and N-iminoethyl-L-ornithine administration. METHODS: The study included 50 adult male Wistar albino rats (weighing 350 to 400 g). Rats were randomly allocated into four groups. Except in the control, moderate-level pulmonary contusion was created in all other groups. Intraperitoneal saline solution was performed in groups 1 and 2, 25 mg.kg-1 Ngamma-nitro-L-arginine methyl ester in group 3, and 20 mg.kg-1 N-iminoethyl-L-ornithine in group 4. Blood and lung tissues were studied biochemically and histopathologically. RESULTS: Best outcomes were recorded statistically significantly in groups with administration of Ngamma-nitro-L-arginine methyl ester and N-iminoethyl-L-ornithine when malondialdehyde response, mucous and histopathological values were examined. Significant improvement was detected in superoxide dismutase values in the group with administration of competitive nitric oxide synthase inhibitor Ngamma-nitro-L-arginine methyl ester. Nitric oxide values were substantially decreased in N-iminoethyl-L-ornithine group, while no significance was detected. CONCLUSION: Free oxygen radicals and lipid peroxidation played a role in pulmonary contusion after blunt lung trauma. According to biochemical and histopathological outcomes, effects of inflammation were decreased and protective effects were formed with administration of both Ngammanitro- L-arginine methyl ester and N-iminoethyl-L-ornithine.

Effects of YC-1 on learning and memory functions of aged rats.

BACKGROUND: The aim of this study was to investigate the effects of a potent nitric oxide-guanylate cyclase activator, 3-(5'-hydroxymethyl-2'-furyl)-1-benzylindazole (YC-1), on learning and memory functions in aged rats. MATERIAL AND METHODS: Rats were divided into 2 groups as 4-month-old and 24-month-old rats. Rats received YC-1 (1 mg/kg/day) for 2 weeks long-term. Morris water maze (MWM) and passive avoidance (PA) tests were used to determine learning and memory functions. RESULTS: In the MWM test, there is a significant increase in the acquisition latency (1-4 days) of 24-month-old rats. There is a significant reduction in the "time spent in the escape platform's quadrant" in 24-month-old rats compared to 4-month-old rats in the probe trial of the MWM test. YC-1 treatment reversed the reduction of the "time spent in the escape platform's quadrant" of 24-month-old rats. In the PA test, there was no significant difference in the 1st-day latency of rats in all groups. On the 2nd day, retention latency significantly decreased in the 24-month-old rats compared to 4-month-olds. YC-1 reversed the diminished retention latency in 24-month-old rats. YC-1 treatment and aging did not affect results of the locomotor activity test or the foot-shock sensitivity test, suggesting our results were not due to a change in motor activity or disability of the animals. CONCLUSIONS: Our findings suggest that activation of the NO-sGC-cGMP pathway plays an important role in spatial and emotional learning and memory functions in aged rats.

Effect of locally applied transforming growth factor Beta3 on wound healing and stenosis development in tracheal surgery.

BACKGROUND: Tracheal stenosis constitutes one of the most frequently seen problems in thoracic surgery. Although many treatment modalities to prevent fibroblast proliferation, angiogenesis, or inflammation that causes tracheal stenosis have been attempted, an effective method has not yet been found. In this study, a transforming growth factor beta3 (TGF-ß3)/chitosan combination was used for this purpose. METHODS: A slow-release preparation containing a thin layer of TGF-ß3 with a chitosan base was made. Thirty albino Wistar rats were divided into 3 groups. A full-layer vertical incision was made in the anterior side of the trachea of each rat between the second and fifth tracheal rings. The tracheal incision was sutured. Group A was evaluated as the control group. In Group B, a chitosan-based film was placed on the incision line. In Group C, a slow-release TGF-ß3/chitosan-coated substance was placed on the incision line. The rats were killed on day 30, and their tracheas were excised by cutting between the lower edge of the thyroid cartilage and the upper edge of the sixth tracheal ring together with the esophagus. Epithelialization, fibroblast proliferation, angiogenesis, inflammation, and collagen levels were evaluated histopathologically by the same histopathologist. RESULTS: Statistically significant differences were not found among the 3 groups. Cold abscesses were observed at the incision sites in both the TGF-ß/chitosan and chitosan groups. These were thought to have formed due to the chitosan. CONCLUSIONS: As this was the first experiment in the literature to use this type of TGF-ß3 formulation, we intend to change the formulation and perform this study again with a different TGF-ß3/chitosan preparation.

Effects of Ankaferd Blood Stopper and Celox on the tissue factor activities of warfarin-treated rats.

The aim of this study is to evaluate the effect of these new generation hemostatic agents on early-stage soft tissue healing of warfarin-treated rats by measuring the tissue factor (TF) activities. Rats in the warfarin group were treated intraperitonally with 0.1 mg/kg warfarin, and rats in the control group were treated with 1 mL/kg saline. All rats had 3 incisions on dorsal dermal tissue applied Celox, Ankaferd Blood Stopper (ABS), or no hemostatic agent. Six rats from each group were killed on day 4, and the other 6 were killed on day 8. Prothrombin time (PT) and TF activities were evaluated, respectively. Both the hemostatic agents positively affected the hemostasis. Warfarin treatment increased the PT levels as expected. Celox-treated dermal tissues had higher TF activity when compared to ABS-treated ones. The ABS affected the early-stage healing positively in clinical aspect, whereas Celox was more effective on hemostasis by means of increasing TF activities.

Effects of long-term etanercept treatment on anxiety- and depression-like neurobehaviors in rats.

Growing evidence indicates that there is a correlation between depression and inflammation. Administration of anti-tumor necrosis factor (TNF) agents for treatment of chronic inflammatory diseases, such as psoriasis, was associated with decreased depressive symptoms and increased quality of life in some clinical studies. The aim of the present study was to investigate the effects of chronic etanercept, a TNF-α inhibitor, on anxiety- and depression-like neurobehaviors in rats. Male rats were treated for 8 weeks with either saline or etanercept (0.8 mg/kg/week, subcutaneously). The anxiety levels of rats were evaluated using the elevated plus maze, a classical rodent model of anxiety and depression was measured using the force swimming test, a behavioral despair task. The anxiety-like neurobehaviors of the animals were found significantly decreased after the etanercept treatment. Etanercept significantly decreased immobility time in rat model of despair test, seemed to have an antidepressive effect in rats. Compared to saline treatment, long-term etanercept treatment had no effect on the total number and pattern of locomotor activities. Findings of the study supported the hypothesis that TNF-α has a role in the modulation of emotional processes and its inhibition may represent a novel strategy for the treatment of affective disorders.

Selective and nonselective neuronal NOS inhibitors impair cognitive function in the three panel runway and passive avoidance tasks in rats.

The aim of this study was to compare the effects of both neuronal NOS (nNOS) and inducible NOS (iNOS) inhibitor 2-iminobiotin, with the more selective nNOS inhibitor N(ω)-propyl-L-arginine (NPLA) and selective inducible NOS (iNOS) inhibitor aminoguanidine, on emotional learning, working memory and reference memory, by using three panel runway and passive avoidance paradigm in order to clarify the role of distinct isoforms of NOS in the regulation of learning and memory functions. NPLA and 2-iminobiotin significantly increased the number of errors and latency of working and reference memory performances of rats in three panel runway paradigm and impairs retention for the passive avoidance task. However, aminoguanidine did not affect cognitive functions in three panel runway and passive avoidance test. The effect of NPLA and 2-iminobiotin was reversed by pretreatment with a NOS substrate L-arginine. In conclusion, NPLA and 2-iminobiotin impaired cognitive functions in different kind of tasks used in this study and the effect of NPLA and 2-iminobiotin was found to be NO-dependent. Our results may confirm that nNOS plays the key role on emotional learning, working memory and reference memory in rats.