Experimental and Toxicologic Pathology最新文献

Background

Medullary thyroid carcinoma (MTC), defined as a malignant tumour with C-cell differentiation, is of neuroendocrine origin and is characterized by the synthesis and secretion of calcitonin (CT). MTC without CT secretion has been reported on rare occasions. The purpose of this study was to evaluate the histological, immunohistochemical, and molecular pathologic features as well as the clinical significance of non-secretory MTC (NCR-MTC).

Methods

A retrospective analysis of patients with NCR-MTC was performed. The clinical features of NCR-MTC, including age, gender, tumour size and number, clinical signs of hypocalcaemia and diarrhoea, and the presence of lymph node metastasis, as well as the pathologic features of the disease, including tumour morphology, presence of neuroendocrine structures, capsular invasion, and immunohistochemical expression and presence of mutations in the RET gene, were evaluated.

Results

Nineteen patients with NCR-MTC were identified among 158 patients with MTC, resulting in a prevalence rate of 12.02%. Patients with NCR-MTC typically had masses less than 1 cm in size (73.7%, 14/19). Hypocalcaemia was not present in 94.7% (18/19) of patients. While 42.1% (8/19) of patients with NCR-MTC did not have amyloid deposits, only 18% (25/139) of patients with secretory MTC did not have such deposits. While 95.7% (133/139) of the control group of patients with secretory MTC had neuroendocrine tumour structure, only 84.2% (16/19) of the patients with NCR-MTC had this type of tumour structure. Patients with NCR-MTC were also less likely to have vascular tumour thrombus, lymph node metastasis or thyroid capsular invasion. With regard to immunohistochemistry, CT expression was mostly negative, and carcinoembryonic antigen (CEA) expression was positive in 21.1% (4/19) of patients with NCR-MTC, while only 5.8% (8/139) of patients in the control group had positive CEA expression.

Conclusions

The prevalence of NCR-MTC was low (12.02%). This type of tumour was smaller in size and more differentiated. Compared with the control group, relatively few patients had obvious symptoms, hypocalcaemia, lymph node metastasis, thyroid capsular or vascular invasion, or tumours with amyloid or neuroendocrine tumour structure.

The chitosan-caffeic acid (CCA) conjugate shows a hepatoprotective effect against oxidative stress-induced hepatic damage in cultured hepatocytes. The objective of this study is the verification of the hepatoprotective effect of the CCA in vivo against ethanol-induced liver injury in mice. The administration of ethanol resulted in the increase of the serum-aminotransferase activities (AST and ALT), triglycerides, total cholesterol, and lipid peroxidation. The CCA co-administration, however, significantly (p < 0.05) ameliorated these serum biomarkers. The antioxidant-enzyme activities in the liver tissue, including those of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx), were significantly decreased by a chronic ethanol administration, whereas the hepatic lipid-peroxidation level was increased. Moreover, the chronic ethanol administration elevated the gene expression of pro-inflammatory cytokines such as tumor-necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in the liver tissue. The CCA co-administration, however, significantly (p < 0.05) increased the activities of the SOD, CAT, and GPx and caused the down-regulation of the TNF-α- and IL-6-gene expressions in the liver tissue. An histopathologic evaluation also supported the hepatoprotective effect of the CCA against ethanol-induced hepatotoxicity in the mice.

The present study aimed to examine the putative preventive effect of the ethanolic extract Date Palm Pollen (DPP, Phoenix dactylifera L., family Arecaceae) on isoproterenol-induced myocardial infarction (MI) in rats. Twenty four rats were randomly divided into four groups including control. They were treated with DPP extract (400 mg/kg) and clopidogrel (0.2 mg/kg) for 7 days followed by myocardial injury induction using subcutaneous isoproterenol (100 mg/kg) with an interval of 24 h for two days (6th and 7th day). Administration of isoproterenol exhibited indicative changes in the ECG pattern evidenced by significant elevation of ST-segment and cardiac injury markers viz.; troponin-T, creatine phosphokinase (CPK), alanine aminotransferase (ALT) and lactate dehydrogenase (LDH) by 315%, 71%, 64% and 170%, respectively as compared to control. Additionally, the angiotensin-converting enzyme (ACE) activity in plasma was increased by 33% associated to histological myocardial necrosis. However, pre-co-treatment with DPP extract improved the cardiac biomarkers injury, normalized cardiac function indices and prevented the ventricular remodeling process through inhibition of ACE activity by 34% and the inhibition of the generation of radical oxygen species. Extensive characterization of this DPP extract using LC-HRMS revealed numerous flavonoids and phenols compounds which could be endowed with cardiopreventive actions. Overall, these results proved that DPP extract has preventive effects on cardiac remodeling process.

Esculetin is a polyphenolic compound with cytoprotective properties. We previously demonstrated the induction of apoptosis by esculetin in NB4 human leukemia cells, as a model, by a mechanism not well understood. To analyse the antioxidant activity of esculetin on apoptosis, we have studied the influence of co-treatments of esculetin at a concentration of 100 μM with exogenous ROS donors, namely tert-butyl-hydroperoxide and hydrogen peroxide, on NB4 cells. Esculetin (100 μM) exerts a protective effect on cell viability and death necrosis or late apoptosis caused by the oxidant t-BHP whereas it potentiates decrease of cell viability and cell death caused by H₂O₂. In the first case, the O₂⁻ scavenging activity of esculetin (100 μM) could be implicated. In the last one, cytotoxicity by apoptosis induction seems to be related to the increase in O₂⁻, among other possible mechanisms. These results contribute to the study of the antitumor properties of esculetin by regulation of redox balance in leukemia cells.

Although still a matter of controversial discussion, skeletal myoblasts are one of the options for stem cell transplantation improving cardiac function after myocardial infarction, exhibiting several advantages including the availability, the ability of self-renewal and differentiation, and the lack of ethical and immunological problems. The aim of this study was to investigate the impact of stem cell therapy with skeletal myoblasts on experimental venous bypass grafts in a mouse model of vein graft disease.

Forty C57BL/6J mice underwent bypass grafting interposing a venous bypass graft of the donor mouse into the carotid artery of the recipient mouse.

Twenty mice received periadventitially treatment with 1 million fluorescence labeled skeletal myoblasts suspended in culture medium (treatment group), the other twenty mice received only culture medium without myoblasts (control group).

Two weeks after bypass surgery, the vein grafts of all 40 mice were harvested, stained and histologically investigated under light and immunofluorescence microscope.

Against our expectations, skeletal myoblasts stayed in place and were still located in the adventitia after bypass grafting. Additionally, vein grafts of the myoblast group revealed a 2fold increased neoneointima formation, a decreased media thickness, a slightly increased neovascularization, a higher percentage of reendothelialization and also a slightly higher percentage of PDGFR ɑ, PDGFR ß, MMP-7 and MMP-9 positive cells, suggesting a paracrine mechanism responsible for accelerated neointima formation.

In conclusion, the results of our study do not support the use of skeletal myoblast for the treatment of vein graft disease after coronary artery bypass surgery.

In the present study, histological, morphometrical and ultrastructural analysis were performed to investigate intestinal mucosa changes in piglets exposed to deoxynivalenol alone or associated with two strains of Lactobacillus plantarum and the respective culture supernatants. Jejunal explants were incubated for 4 h in culture medium with a) only culture medium (DMEM, control group), b) deoxynivalenol (DON, 10 μM), c) heat-inactivated Lactobacillus plantarum strain1 − LP1 (1.1 × 10⁸ CFU/ml) plus DON, d) heat-inactivated Lactobacillus plantarum strain2–LP2 (2.0 × 10⁹ CFU/ml) plus DON, e) heat-inactivated Lactobacillus plantarum strain1 culture supernatant (CS1) plus DON, and f) heat-inactivated Lactobacillus plantarum strain1 culture supernatant (CS1) plus DON. Explants exposed to DON and DON plus LP1 and LP2 showed a significant increase in histological changes (mainly villi atrophy and apical necrosis) and a significant decrease in villi height when compared to unexposed explants. However, explants treated with CS1 + DON and CS2 + DON remained similar to the control group both in histological and morphometrical aspects. DON also induced a significant decrease in goblet cell density compared to control whereas CS1 + DON treatment induced an increase in the number of goblet cells in comparison to DON explants. In addition, ultrastructural assessment showed control, CS1 + DON and CS2 + DON explants with well delineated finger shape villi, meanwhile DON-treated, LP1 + DON and LP2 + DON explants showed a severe villi atrophy with leukocytes exudation on the intestinal surface. Taken together, our results indicate that the culture supernatant treatment reduced the toxic effects induced by DON on intestinal tissue and may contribute as an alternative strategy to reduce mycotoxin toxicity.

Sterigmatocystin (ST) is generally recognized as a potential carcinogen, mutagen and teratogen. Studies showed that ST could induce adenocarcinoma of lung in mice in vivo and DNA damage, cell cycle arrest in a human immortalized bronchial epithelial cell line (BEAS–2 B cells) and a human lung cancer cell line (A549 cells) in vitro. Besides, ST could induce G₂ arrest (cell cycle arrest in G₂ phase) in several other cells. Cell cycle arrest may be one of the common toxic effects of ST. As cells may undergo apoptosis or death due to cell cycle arrest, we wondered whether apoptosis is another common effect of ST in different cells in vitro. In the present study, we studied the effects of ST on proliferation and apoptosis in A549 cells and BEAS–2 B cells with 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay and flow cytometric analysis (FCM). The MTT results showed that proliferation inhibition following ST treatment for 24 h was observed in both A549 and BEAS–2 B cells in vitro. And increased apoptosis by FCM was also found after ST treatment. Down-regulation of Bcl-2, up-regulation of Bax and the activation of caspase-3 after ST treatment were detected by western blotting analyses. The results in the present study are consistent with our previous results, which indicated that inducing apoptosis may be a common effect of ST in different cells in vitro.

The degree and consequence of tissue injury are highly regarded during long-term exposure to selective antidepressant fluoxetine. Melatonin has been shown to palliate different lesions by scavenging free radicals, but its role in the reduction of the fluoxetine-induced injuries has been little known.

Thirty-six mature male Wistar rats were randomly assigned into control and experimental groups. The experimental rats were included as following; 24 mg/kg/bw fluoxetine for 4 weeks; 1 mg/kg/bw melatonin for 4 weeks; fluoxetine + 1-week melatonin, fluoxetine + 2-week melatonin and fluoxetine + 4-week melatonin. In the current experiment, we investigated weight gain, hematological and biochemical parameters, pathological injuries and oxidative status.

We noted the positive effect of melatonin in weight loss of fluoxetine-treated rats (p < 0.05). The significant reduction of superoxide dismutase, glutathione peroxidase, catalase activities in blood, liver, and kidneys and changes in serum total antioxidant capacity caused by fluoxetine were reversed by melatonin (p < 0.05). Melatonin reduced the increased lipid peroxidation and transaminase activity in rats received fluoxetine (p < 0.05). We also showed the potency of fluoxetine in inducing leukopenia, thrombocytopenia and hypochromic and macrocytic anemia which was blunted by melatonin. Both RBCs and platelets indices were also corrected. Rats received melatonin in combination with fluoxetine showed a reduction in the severity of degeneration and inflammatory changes in different tissues, brain, heart, liver, lungs, testes and kidneys as compared to the fluoxetine group.

Therefore, melatonin fundamentally reversed the side effects of fluoxetine in the rat model which is comparable to human medicine.

We, herein, investigated the in vitro effects of argininic acid on thiobarbituric acid-reactive substances (TBA-RS), total sulfhydryl content and on the activities of antioxidant enzymes such as catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in the blood, kidney and liver of 60-day-old rats. We also verified the influence of the antioxidants (each at 1.0 mM) trolox and ascorbic acid, as well as of N^G-nitro-l-arginine methyl ester (L-NAME) at 1.0 mM, a nitric oxide synthase inhibitor, on the effects elicited by argininic acid on the parameters tested. The liver, renal cortex and renal medulla were homogenized in 10 vol (1:10w/v) of 20 mM sodium phosphate buffer, pH 7.4, containing 140 mM KCl; and erythrocytes and plasma were prepared from whole blood samples obtained from rats. For in vitro experiments, the samples were pre-incubated for 1 h at 37 °C in the presence of argininic acid at final concentrations of 0.1, 1.0 and 5.0 μM. Control experiments were performed without the addition of argininic acid. Results showed that argininic acid (5.0 μM) enhanced CAT and SOD activities and decreased GSH-Px activity in the erythrocytes, increased CAT and decreased GSH-Px activities in the renal cortex and decreased CAT and SOD activities in the renal medulla of 60-day-old rats, as compared to the control group. Antioxidants and/or L-NAME prevented most of the alterations caused by argininic acid on the oxidative stress parameters evaluated. Data suggest that argininic acid alters antioxidant defenses in the blood and kidney of rats; however, in the presence of antioxidants and L-NAME, most of these alterations in oxidative stress were prevented. These findings suggest that oxidative stress may be make an important contribution to the damage caused by argininic acid in hyperargininemic patients and that treatment with antioxidants may be beneficial in this pathology.