Oxidative stress and apoptosis are proposed mechanisms of cellular injury in studies of xenobiotic hepatotoxicity. This study is focused on addressing the mutual relationship and early signals of these mechanisms in the D-galactosamine and lipopolysaccharide (D-GalN/LPS) hepatotoxicity model, with the help of standard liver function and biochemistry tests, histology, and measurement of gene expression by RT-PCR. Intraperitoneal injection of 400 mg/kg D-GalN and 50 μg/kg LPS was able to induce hepatotoxicity in rats, as evidenced by significant increases in liver enzymes (ALT, AST) and raised bilirubin levels in plasma. Heme oxygenase-1 and nitric oxide synthase-2 gene expressions were significantly increa sed, along with levels of their products, bilirubin and nitrite. Th e gene expression of glutathione peroxidase 1 remained unchanged, whereas a decrease in superoxide dismutase 1 gene expression was noted. Furthermore, the significant increase in the gene expression of apoptotic genes Bid, Bax and caspase-3 indicate early activation of apoptotic pathways, which was confirmed by histological evaluation. In contrast, the measured caspase-3 activity remained unchanged. Overall, the results have revealed differential oxidative stress and apoptotic responses, which deserves further investigations in this hepatotoxicity model., N. Lekić ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
The parasitoid wasp Dinocampus coccinellae has been reported to parasitise adult, pupal and larval coccinellids. Field samples of larvae and pupae of Coccinella septempunctata, collected over 13 years in Britain, have failed to reveal any infected pre-imaginal individuals. The parasitisation rates of D. coccinellae into pre-imaginal and adult C. septempunctata were assessed in both choice and no-choice tests. Observations and test results revealed that British D. coccinellae have a strong preference to oviposit in adult coccinellids rather than larvae or pupae. This preference decreases as wasps age if denied oviposition opportunities.
The glycophenotyping of mammalian cells with plant lectins maps aspects of the glycomic profile and disease-associated alterations. A salient step toward delineating their functional dimension is the detection of endogenous lectins. They can translate sugar-encoded changes into cellular responses. Among them, the members of the lectin family of galectins are emerging regulators of cell adhesion, migration and proliferation. Focusing on galectins-1, -3 and -7, we addressed the issue whether their expression is regulated during wound healing in porcine skin as model. A conspicuous upregulation is detected for galectin-1 in the dermis and a neoexpression in the epidermis, where an increased level of galectin-7 was also found. Applying biotinylated tissue lectins as probes, the signal intensities for accessible binding sites decreased, intimating an interaction of the cell lectin with reactive sites. In contrast, galectin-3 parameters remained rather constant. Of note, epidermal cells in culture also showed an increase in expression/presence of galectin-1, measured on the levels of mRNA and protein, in this case by Western blotting and quantitative immunocytochemistry. Used as matrix, galectin-1 conferred resistance to trypsin treatment to attached human keratinocytes and reduced migration into scratch-wound areas in vitro. This report thus presents new information on endogenous lectins in wound healing and differential regulation among the three tested cases., J. Klíma ... [et al.]., and Obsahuje seznam literatury
We have investigated the role of m- and k-opioid receptors in the central control of preovulatory LH and FSH release in the proestrous rat. Animals were anesthetized with chloral hydrate at 14:00 h on proestrus day. Following femoral artery cannulation, they were mounted in a stereotaxic apparatus. Morphine and U-50488H (benzene-acetamide methane sulphonate) were infused intracerebroventricularly either alone or in combination with naloxone and MR1452, respectively. Controls received sterile saline alone. Blood samples were obtained at hourly intervals between 15:00 h and 17:00 h. Plasma LH and FSH levels were measured by radioimmunoassay. Morphine did not significantly change plasma LH levels at 15:00 h and 16:00 h sampling intervals. A significant increase was observed at 17:00 h compared to the controls (p<0.05). U-50488H significantly increased LH levels at 16:00 h and 17:00 h (p<0.05). The co-administration of naloxone and MR1452 with m- and k-agonist had no significant effect on LH levels at any sampling interval. In all groups, LH levels showed a linear rise over the sampling period between 15:00 h and 17:00 h. None of the treatments significantly altered plasma FSH levels which however, declined towards the end of the afternoon surge. In conclusion, we suggest that the secretion of LH and FSH is differentially regulated by m- and k-opioid receptors. It is thought that in all groups chloral hydrate interfered with the LH surge secretory systems., S. Kumru, M. Şimşek, B. Yilmaz, E. Sapmaz, S. Kutlu, S. Sandal, S. Canpolat., and Obsahuje bibliografii
High blood pressure, increased level of cholesterol, diabetes, hypertriglyceridemia and obesity are risk factors accompanied metabolic syndrome. The aim of the study was to compare geometry of carotid artery (AC) of 3-week-old (3w) and 52-week-old (52w) hereditary hypertriglyceridemic rats (hHTG) and spontaneously hypertensive rats (SHR) which represent a genetic model of human essential hypertension with age-matched Wistar rats. After sacrificing the rats were perfused with a glutaraldehyde fixative under the pressure 90 mm Hg (3w) and 120 mm Hg (52w) for 10 min via cannula placed into left ventricle. Middle part of AC was excised and processed according to standard electron
microscopy procedure. Geometry of AC was evaluated in light microscopy. SHR vs. Wistar rats: BP of 3w did not differ, in 52w it was increased; cardiac hypertrophy was found in both ages; wall thickness (WT) and cross sectional area (CSA) in 3w did not differ, in 52w both were increased; inner diameter (ID) in 3w and 52w was decreased; WT/ID was increased in both ages. Hereditary HTG vs. Wistar rats: BP was increased in both periods; cardiac hypertrophy was observed in 3w; WT in 3w was decreased, in 52w it was increased; CSA and ID were decreased in both ages; WT/ID was increased only in 52w. Discrepancies between development of BP, cardiac hypertrophy in SHR and hHTG rats were observed. Alterations of BP were not in harmony with alterations in geometry of carotid arteries in both SHR and hHTG rats. We suggest that BP is not the main stimuli evoked hemodynamic and structural alterations of cardiovascular system in ontogenic development of SHR and hHTG rats.
Fecundity and growth allocation to reproduction were investigated in stream-dwelling threespine Gasterosteus aculeatus L. (leiurus) and ninespine Pungitius pungitius (L.) sticklebacks of St. Ippollitts Brook, Hertfordshire (England), between August 1993 and October 1994. We compared oocyte size distributions as well as the relative fecundity of females containing mature oocytes, compared growth allocation to gonadal growth and overall reproductive allocation from estimates of total egg supply, the number of reserve oocytes eventually spawned, the proportion of reserve oocytes not spawned, the total number of oocytes spawned, and the number of egg clutches per season. Notable differences in reproductive strategy were observed between the two species. Ninespine sticklebacks were smaller in size than threespine, but compensated for this through a smaller size at first maturity, an almost equal seasonal fecundity (number of spawned oocytes) accompanied by a higher number of unspawned oocytes (i.e. maintenance of a low mature-to-total oocyte ratio), an extended spawning period, a higher number of clutches, and an overall lower reproductive allocation.
a1_With hypoxic stress, hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) are elevated and their responses are altered in skeletal muscles of plateau animals [China Qinghai-Tibetan plateau pikas (Ochotona curzoniae )] as compared with control animals [normal lowland Sprague-Dawley (SD) rats]. The results indicate that HIF-1α and VEGF are engaged in physiological functions under hypoxic environment. The purpose of the current study was to examine the protein levels of VEGF receptor subtypes (VEGFRs: VEGFR-1, VEGFR-2 and VEGFR-3) in the end organs, namely skeletal muscle, heart and lung in response to hypoxic stress. ELISA and Western blot analysis were employed to determine HIF-1α and the protein expression of VEGFRs in control animals and plateau pikas. We further blocked HIF-1α signal to determine if HIF-1α regulates alternations in VEGFRs in those tissues. We hypothesized that responsiveness of VEGFRs in the major end organs of plateau animals is differential with insult of hypoxic stress and is modulated by low oxygen sensitive HIF-1α. Our results show that hypoxic stress induced by exposure of lower O2 for 6 h significantly increased the levels of VEGFR-2 in skeletal muscle, heart and lung and the increases were amplified in plateau pikas. Our results also demonstrate that hypoxic stress enhanced VEGFR-3 in lungs of plateau animals. Nonetheless, no significant alternations in VEGFR-1 were observed in those tissues with hypoxic stress. Moreover, we observed decreases of VEGFR-2 in skeletal muscle, heart and lung; and decreases of VEGFR-3 in lung following HIF-1α inhibition. Overall, our findings suggest that in plateau animals 1) responsiveness of VEGFRs is different under hypoxic environment; 2) amplified VEGFR-2 response appears in skeletal muscle, heart and lung, and enhanced VEGFR-3 response is mainly observed in lung; 3) HIF-1α plays a regulatory role in the levels of VEGFRs. Our results provide the underlying cellular and molecular mechanisms responsible for hypoxic environment in plateau animals, having an impact on research of physiological and ecological adaptive responses to acute or chronic hypoxic stress in humans who living at high attitude and who live at a normal sea level but suffer from hypoxic disorders., H.-C. Xie, J.-G. Li, J.-P. He., and Obsahuje bibliografii
This study evaluated right ventricular (RV) and left ventricular (LV) diastolic tolerance to afterload and SERCA2a, phospholamban and sodium-calcium exchanger (NCX) gene expression in Wistar rats. Time constant and end diastolic pressure-dimension relation (EDPDR) were analyzed in response to progressive RV or LV afterload elevations, induced by beat-to-beat pulmonary trunk or aortic root constrictions, respectively. Afterload elevations decreased LV-, but increased RV-. Whereas LV- analyzed the major course of pressure fall, RV- only assessed the last fourth. Furthermore, RV afterload elevations progressively upward shifted RV EDPDR, whilst LV afterload elevations did not change LV-EDPDR. SERCA2a and phospholamban mRNA were similar in both ventricles. NCX-mRNA was almost 50 % lower in RV than in LV. Left ventricular afterload elevations, therefore, accelerated the pressure fall and did not induce diastolic dysfunction, indicating high LV diastolic tolerance to afterload. On the contrary, RV afterload elevations decelerated the late RV pressure fall and induced diastolic dysfunction, indicating small RV diastolic tolerance to afterload. These results support previous findings relating NCX with late Ca2+ reuptake, late relaxation and diastolic dysfunction.
We have recently found that both vanadate and vanadyl inhibit ATP-dependent succinyl-CoA synthetase (A-SCS) solubilized from the rat brain mitochondria. Aim of the present study was to estimate a proportion of A-SCS to G-SCS in adult and 5-day-old rat brain and their susceptibility to vanadium ions. The G-SCS to A-SCS ratio of 5-day-old brains was by 196 % higher than that in adults. This is in accordance with previous observation that G-SCS is high in tissues metabolizing ketone bodies. Both G-SCS and A-SCS differ in their susceptibility towards vanadium ions. A-SCS of adult brain was more sensitive to vanadate (IC 50 1.6.10'5 mol.I"1) than was G-SCS (IC 50 6.2.10"5 molT1). On the contrary G-SCS was more sensitive to vanadyl (IC 50 3.5.10^ mol.I1) than was A-SCS (IC 50 9.0.10-4 mol.I1). Also autophosphorylation of G-SCS a-subunit was more resistant to vanadate than A-SCS. In contrast to the adult SCS forms, almost equal susceptibility of A-SCS and G-SCS to vanadyl and vanadate was observed in infant brains. The results suggest some structural (functional) differences between two SCS forms in adults and also between infant and adult G-SCS.