Hepatotoxicity induced by gibberellic acid in adult rats and their progeny

Gibberellic acid (GA₃), a plant growth regulator, was largely used in agriculture of many countries including Tunisia. However, its potential hazardous effects on human health were relatively unexplored. The purpose of this study was to investigate the effects of GA₃ on hepatic function in female rats and their pups. Animals were given daily 200 ppm GA₃ in drinking water from the 14th day of pregnancy until day 14 after delivery. It was found that GA₃ induced liver damages as evidenced by the elevation of plasma aminotransferases (ALT, AST), lactate dehydrogenase activities, bilirubin and albumin levels. Hepatotoxicity was objectified by the significant increase of malondialdehyde (MDA) level and a decrease of antioxidant enzyme activities such as catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione content in liver of suckling pups and their mothers. Impairment of hepatic function corresponded histologically. We have observed blood vessels congestion and leucocytes infiltration, which were more pronounced in hepatocytes of dams than those of suckling pups.Results of this current study suggest that exposure rats to GA₃ induces hepatotoxicity and histopathological changes in liver of female rats and their progeny.     

三聚氰胺对孕鼠胎盘和仔鼠的影响

目的探讨三聚氰胺暴露对孕鼠胎盘及其子代的影响。方法 3月龄雌性Wistar大鼠48只,经适应性饲养并受孕后随机分为4组,每组12只。孕期给予三聚氰胺灌胃染毒,灌胃剂量分别为对照组0 mg/(kg·d)、低剂量组400mg/(kg·d)、中剂量组800 mg/(kg·d)、高剂量组1200mg/(kg·d),连续染毒14天,观察三聚氰胺对孕鼠胎盘及仔鼠的影响。结果高剂量组仔鼠的体重(3.87±0.15)g、身长(3.77±0.07)cm、尾长(1.41±0.03)cm、窝重(54.49±5.51)g均显著降低,与其他三组比较差异有统计学意义。高剂量组的不良妊娠结局(死胎、吸收胎)增多、活胎数减少。受精卵着床数、胎盘重各组间相比差异无统计学意义。高剂量组胎盘海绵带滋养叶巨细胞及空泡化细胞岛增多,迷路带滋养叶细胞呈退行性改变,绒毛肿胀增粗、间隙变窄,绒毛周围纤维蛋白沉积增多,组织淤血严重。其他剂量组胎盘结构无明显改变。中剂量组和高剂量组仔鼠肾脏中均出现结晶状物质,并且高剂量组仔鼠肾脏有炎性改变。结论三聚氰胺可能具有胚胎毒性,胎盘组织是其发挥毒性作用的靶器官之一。孕期长期暴露于高剂量三聚氰胺可能对胎盘滋养细胞有损伤作用,从而影响了胎盘的血液供应及母胎间营养物质和氧气的交换,导致其子代生长发育不良。     

Adolescent pregnancy and growth of progeny in rats

The relationship between very young adolescent mothers and their progeny was studied in terms of fetal development and pup growth. The mothers used in this study had just attained puberty and were still growing; their body weight was about half that of normal full-grown adult females. Still, they were able to conceive and to maintain gestation but growth and skeletal development of their fetuses was significantly retarded. Adolescent dams took in more food during gestation, and about 60% of the intake was used to meet their own growth and development need rather than that of their progeny. During lactation, adolescent dams took in about the same amount of food as did the control, but the pups they were suckling gained significantly less weight than did pups suckled by the control. Retardation of growth and development during gestation, and the continued retardation during lactation, can best be explained by an overall nutritional competition between adolescent dams and their offspring.     

Cobalt chloride induces hepatotoxicity in adult rats and their suckling pups

To assess liver damages in pregnant and lactating rats and in their suckling pups, wistar female rats were given through drinking water 350 ppm of CoCl₂ (157 ppm Co²⁺) from the 14th day of pregnancy until day 14 after delivery. The effects of cobalt chloride on lipid peroxidation levels, antioxidant enzyme activities, lipid profile and histopathology aspects of liver were evaluated. Biochemical results showed that lipid peroxidation increased significantly in Co-treated rats, as evidenced by high liver thiobarbituric acid-reactive substance (TBARS) levels. Alteration of the antioxidant system in treated group was confirmed by the significant decline of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) activities and reduced glutathione (GSH) content in liver of suckling pups and their mothers. Moreover, CoCl₂ exposure induced an increase in the activities of the aspartate transaminase (AST), alanine transaminase (ALT), lactate deshydrogenase (LDH) and bilirubin levels in pups and their mothers while liver LDH activity and plasma albumin level were significantly decreased. On the other hand, cobalt chloride induced a marked hypoglycemia, a significant decline in triglycerides and total cholesterol levels. Histological studies showed an infiltration of mononuclear cells and vascular congestion in liver of pups and their mothers.Based on the present findings, exposure of rats to CoCl₂ during late pregnancy and early postnatal period affects antioxidant enzyme activities and lipid peroxidation indicating liver damage in mothers and their offspring.     

Peptidergic correction of behavior in adult progeny of albino rats exposed to acute hypoxia during early organogenesis

Physical development, spontaneous behavior, and training capacity were evaluated in adult progeny of albino rats exposed to acute hypobaric hypoxia on days 9–10 of gestation, corresponding to the early organogenesis period. Prenatal hypoxia caused delayed behavioral disorders, which were more pronounced in females born from mothers with low resistance to hypoxia. Therapeutic intranasal administration of Pro-Gly-Pro peptide in a dose of 1 mg/kg to rat pups on days 13–15 of life completely prevented the negative consequences of acute prenatal hypoxia in adult females and leveled virtually all negative consequences, except delayed physical development, in males. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 142, No. 7, pp. 38–41, July, 2006     

Histophysiology of ovaries and adrenal glands in rats and brain development in their progeny: Correlation and cluster analysis

Brain weight of 21-day-old rat fetuses positively correlates with the area of the glomerulosa zone, the ratio of this area to the area of the fasciculata-reticularis zone, activity of hydroxysteroid dehydrogenase in the glomerulosa zone, and the ratio of its activity in the glomerulosa and reticularis zones. In the one-day-old newborns these relationships were absent. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 127, No. 3, pp. 336–339, March, 1999     

Mild hypoxic preconditioning attenuates injury-induced NADPH-d/nNOS expression in brainstem motor neurons of adult rats

Excessive production of nitric oxide (NO) might have detrimental effects on the hypoxia-related neuropathology. This study aimed to test if mild hypoxic preconditioning (MHPC) would attenuate the pathological changes in the brainstem motoneurons having a different functional component after peripheral nerve crush injury (PNCI). Prior to PNCI treatment, young adult rats were caged in the mild hypoxic altitude chamber with 79Torr of the partial oxygen concentration ( pO(2)) (i.e., 0.5atm at 5500m in height) for 4 weeks to adapt the environmental changes. After that, all the animals having successfully crushed both the hypoglossal and vagus nerves (left-side) were allowed to survive for 3, 7, 14, 30 and 60 successive days in normoxic condition. Nicotinamine adenine dinucleotide phosphate-diaphorase (NADPH-d) histochemistry and neuronal nitric oxide synthase (nNOS) immunohistochemistry revealed that MHPC reduces NADPH-d/nNOS expression in the hypoglossal nucleus (HN) and the dorsal motor nucleus of the vagus (DMN) at different time points after PNCI. The morphological findings were further ascertained by Western blot analysis of nNOS and nitrite assay for NO production. Both the morphological and quantitative results peaked at 7 days in HN, whereas for those in DMN were progressively increased up to 60 days following PNCI. The staining intensity of NADPH-d/nNOS(+) neurons, expression of nNOS protein, NO production levels as well as the neuronal loss in HN and DMN of MHPC rats following PNCI were attenuated, especially for those having a longer survival period over 14 days. The MHPC treatment might induce minute amounts of NO to alter the state of milieu of the experimental animals to protect against the PNCI.     

Protective effects of selenium on methimazole nephrotoxicity in adult rats and their offspring

This study aims to investigate the improving effects of selenium on methimazole-induced kidney impairments in adult rats and their pups. The animals were randomly divided into four groups of six each: group I served as control which received standard diet; group II received only methimazole in drinking water as 250 mg/l; group III received both methimazole (250 mg/l, orally) and selenium (0.5 mg/kg of diet); group IV served as a positive control and received selenium (0.5 mg/kg of diet) as sodium selenite (Na₂SeO₃). Treatments were started from the 14th day of pregnancy until day 14 after delivery. In the methimazole-treated group, body and absolute kidney weights decreased in pups and their mothers when compared to control. Daily urine volume, plasma creatinine levels were higher, while urinary levels were lower than in control. Besides, antioxidant enzyme activities, superoxide dismutase, catalase and glutathione peroxidase decreased. Lipid peroxidation recorded an increase revealed by high kidney malondialdehyde levels, while those of plasma and urinary uric acid showed a significant decline. Methimazole-treated rat kidneys exhibited leucocytic infiltrations, vascular congestion and narrowed Bowman's space. Co-administration of selenium through diet improved all the parameters cited above in adult rats and their progeny. Nevertheless, the distorted histoarchitecture in rat kidney was alleviated by selenium treatment. It can then be concluded that selenium is an important protective element that may be used as a dietary supplement against kidney impairments.     

Agmatine attenuates stress- and lipopolysaccharide-induced fever in rats

Physiological stress evokes a number of responses, including a rise in body temperature, which has been suggested to be the result of an elevation in the thermoregulatory set point. This response seems to share similar mechanisms with infectious fever. The aim of the present study was to investigate the effect of agmatine on different models of stressors [(restraint and lipopolysaccharide (LPS)] on body temperature. Rats were either restrained for 4 h or injected with LPS, both of these stressors caused an increase in body temperature. While agmatine itself had no effect on body temperature, treatment with agmatine (20, 40, 80 mg/kg intraperitoneally) dose dependently inhibited stress- and LPS-induced hyperthermia. When agmatine (80 mg/kg) was administered 30 min later than LPS (500 microg/kg) it also inhibited LPS-induced hyperthermia although the effect became significant only at later time points and lower maximal response compared to simultaneous administration. To determine if the decrease in body temperature is associated with an anti-inflammatory effect of agmatine, the nitrite/nitrate levels in plasma was measured. Agmatine treatment inhibited LPS-induced production of nitrates dose dependently. As an endogenous molecule, agmatine has the capacity to inhibit stress- and LPS-induced increases in body temperature.     

Methylcholanthrene-induced tumors in adult and in aging rats: infiltrating cells and their ADCC activity

In our previous studies we found that the slower growth of syngeneic, immunogenic MC-induced sarcoma (MC-Sa) in aging rats was followed by the higher activity of spleen lymphocytes in ADCC assay. The purpose of the present paper was to study infiltrating cells of immunogenic and non-immunogenic MC-Sa and to estimate in situ ADCC activity in relation to the growth of MC-Sa transplants in adult and aging rats. It was found that MC-Sa's were infiltrated mainly by lymphocytes. Among cells infiltrating tumor the high percentage of cells with Fc receptor was present. During progressive tumor growth the percentage of infiltrating cells and also FcR+ cells significantly decreased within immunogenic MC-Sa, but did not change in the case of the non-immunogenic MC-Sa. In cell infiltrates of both tumors no differences between adult and aging rats were observed. At early stages of the tumor growth the cells active in ADCC assay were present within both MC-Sa. The slower growth of immunogenic MC-Sa in aging rats compared with adults was connected with longer maintenance of ADCC activity in situ. In the case of non-immunogenic MC-Sa, which grew at similar rate in both groups of rats, no differences in ADCC activity between adult and aging animals were observed. It is suggested that in situ ADCC activity may be one of the mechanisms responsible for the slower growth of immunogenic MC-Sa in aging rats.     

The influence of alpha-zearalenol on magnesium concentration in cellular subfractions of certain tissues of female rats and their progeny.

The purpose of the research work was to study the influence of alpha-zearalenol on magnesium concentration in cellular subfractions of certain tissues of female rats and their progeny. Pregnant female rats received alpha-zearalenol at the doses of: 0.05, 0.5 or 1 mg x kg(-1) b.w. After delivery, brain, liver and kidneys of female rats and their progeny were removed and magnesium concentration was measured in cellular subfractions of these tissues. Alpha-zearalenol reduced Mg-level in all the cellular subfractions of female rat tissues. In progeny tissues, alpha-zearalenol decreased magnesium concentration in nuclear subfraction only. In mitochondrial and cytosol subfractions it increased Mg-concentration. The changes in magnesium concentration were depended on alpha-zearalenol doses and tissue nature. The magnesium concentration decrease was higher in female rats than in progeny tissues.     

S-nitroso-N-acetylcysteine attenuates liver fibrosis in cirrhotic rats

This study was aimed to investigate the molecular mechanisms underlying prevention of hepatic fibrosis by S-nitroso-N-acetylcysteine (SNAC), a nitric oxide donor that inhibits lipid peroxidation. Secondary biliary cirrhosis was induced by 4 weeks of common bile duct ligation (CBDL). Both sham-operated and CBDL animals received SNAC (6.0 μmol/kg/day) starting 2 weeks after surgery. SNAC treatment reduced the increase in blood enzyme activities (alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase), induced by CBDL. Histological changes were attenuated and there was a significant decrease in the area of liver fibrosis and in the activation of stellate cells measured by alpha-smooth muscle actin (α-SMA) immunostaining. The increase in TBARS concentration and hydroperoxide-induced chemiluminescence were also reduced by SNAC treatment. SNAC down-regulated expression of collagen 1α, α-SMA, tumor necrosis factor-α, tumor growth factor-β, metalloproteinase-2, metalloproteinase inhibitor 1, platelet-derived growth factor (PDGF), and PDGF receptor in CBDL rats. These effects were accompanied by inhibited activation of extracellular signal-regulated kinases, Jun amino-terminal kinases, p38 and Akt. Antifibrotic effects were more efficient than those of the free thiol NAC administered at a dose of 60 μmol/kg. In conclusion, results obtained indicate that SNAC, beyond its antioxidant capacity, exerts antifibrotic effects in rats with secondary biliary cirrhosis by down-regulating increased expression of genes and modulating intracellular signaling pathways that contribute to the accumulation of matrix proteins. Thus, SNAC may be an interesting candidate for the treatment of human fibrosis and cirrhosis.     

Flunarizine pretreatment attenuates hyperthermia-induced extravasation in rats

Previous work has established that there is an increase in endothelial permeability in hyperthermic rats. This work assessed the potential of the calcium channel blocker (E)-1-bis(4-fluorophenyl)methyl-4-(3-phenyl-2-propenyl)piperazine dihydrochloride (flunarizine) as a pretreatment to ameliorate this extravasation. Five groups of male rats (n=12 rats per group, 400-500 g) were given 0, 0.3, 1, 2, or 3 mg/kg flunarizine (FL0, FL0.3, FL1, FL2, and FL3, respectively) by gavage 30 min prior to induction of hyperthermia. Hyperthermia was achieved by placing unrestrained animals in their own cages in a chamber maintained at 41.5 degrees C until a core temperature (Tc) of 42.6 degrees C was attained. Then, 25 mg/kg of Evans blue in saline was administered via a jugular cannula. After 15 min the animals were anesthetized, exsanguinated, tissues removed and washed in saline, and Evans blue extracted with formamide. As the dose of flunarizine was increased, there was a significant (P<0.05) reduction of Evans blue recovered from the liver, kidney, lung, spleen, and intestinal tissue. Endurance time in the heat to reach a Tc of 42.6 degrees C increased significantly from 194+/-39 min (mean+/-SD) with FL0 to 275+/-33 min with FL1, but decreased again with FL2 (206+/-42) and FL3 (199+/-60). Thus, flunarizine pretreatment attenuated hyperthermia-induced extravasation, and 1 mg/kg flunarizine markedly increased the tolerance time to heat exposure.     

Unique dielectric properties distinguish stem cells and their differentiated progeny

The relatively new field of stem cell biology is hampered by a lack of sufficient means to accurately determine the phenotype of cells. Cell-type-specific markers, such as cell surface proteins used for flow cytometry or fluorescence-activated cell sorting, are limited and often recognize multiple members of a stem cell lineage. We sought to develop a complementary approach that would be less dependent on the identification of particular markers for the subpopulations of cells and would instead measure their overall character. We tested whether a microfluidic system using dielectrophoresis (DEP), which induces a frequency-dependent dipole in cells, would be useful for characterizing stem cells and their differentiated progeny. We found that populations of mouse neural stem/precursor cells (NSPCs), differentiated neurons, and differentiated astrocytes had different dielectric properties revealed by DEP. By isolating NSPCs from developmental ages at which they are more likely to generate neurons, or astrocytes, we were able to show that a shift in dielectric property reflecting their fate bias precedes detectable marker expression in these cells and identifies specific progenitor populations. In addition, experimental data and mathematical modeling suggest that DEP curve parameters can indicate cell heterogeneity in mixed cultures. These findings provide evidence for a whole cell property that reflects stem cell fate bias and establish DEP as a tool with unique capabilities for interrogating, characterizing, and sorting stem cells.     

Memantine attenuates 3,4-methylenedioxymethamphetamine-induced hyperthermia in rats

3,4-Methylenedioxymethamphetamine (MDMA) is an illegal drug that can induce life-threatening hyperthermia. No effective pharmacological treatment for MDMA-induced hyperthermia has yet been established. We investigated the effects of memantine, a non-competitive N-methyl-d-aspartate (NMDA)-type glutamate receptor antagonist and an α-7 nicotinic acetylcholine receptor (nAChR) antagonist, on MDMA-induced hyperthermia in rats. Treatment of animals with memantine (10 or 20 mg/kg) either before or after MDMA (10 mg/kg) administration significantly decreased the peak body temperature. Results from our microdialysis study indicated that pretreatment with memantine (20 mg/kg) before MDMA administration had no effect on the MDMA-induced increase in serotonin (5-HT) and dopamine (DA) levels in the anterior hypothalamus. MDMA-induced hyperthermia was significantly suppressed by pretreatment with the non-competitive NMDA receptor antagonist MK-801 (0.5 mg/kg) and the competitive NMDA antagonist CGS 19755 (5 mg/kg), but not by the selective α-7 nAChR antagonist methyllycaconitine (6 or 10 mg/kg). These results indicate that the inhibitory effect of memantine on MDMA-induced hyperthermia may be due to its activity as an NMDA receptor antagonist and not as a result of a direct effect on the 5-HT or DA systems. The present study suggests that moderate doses of memantine may be useful for the treatment of MDMA-induced hyperthermia in humans.     

Morphology of cobalt experimental epilepsy in rats

Rats were made epileptic by intracranial cobalt implants. The brains were studied after hours, days, weeks, and months up to a year. The sequence of morphologic changes was; edema, congestion, and necrosis followed in a few days by minimal acute inflammatory reaction. By the end of the first week, the number of cells was reduced in the adjacent cortex and vacuolar (spongy) degeneration was noted. Silver stain disclosed granularity in and around the lesions by about day 10. Calcium deposition gradually appeared around the lesion within the granular area and became more intense as time went on. In a few weeks, marked proliferation of the fibroblasts, histiocytes, astrocytes, and blood vessels was seen. After a few months the tissue reactions were still present but with lesser degree of intensity. Calcium deposition and blood vessel proliferation, however, seemed to continue to be intense to the end of the experiments. In occasional animals, perivascular cuffing and psammoma bodies were noted. The lesions appear to be of chronic inflammatory type. This could be considered the “cause” for the state of epilepsy, a source of constant lowgrade injury and irritation. However, since other implants in the brain initiate chronic inflammatory reaction without epilepsy, it is our belief that the state of epilepsy could be the result of a more nearly direct effect of cobalt on the brain.