Morphological changes in lungs, placenta, liver and kidneys of pregnant rats exposed to cigarette smoke.

OBJECTIVE: Histopathological examination of changes in foetal and newborn rats, and histopathological and morphometric assessments of changes in lungs, placenta, liver and kidneys of adult rats exposed to cigarette smoke were performed. METHODS: Non-pregnant and pregnant Wistar female rats were exposed to cigarette smoke at a carbon monoxide concentration of 1500 mg/m(3) for 6 h per day, 5 days per week, for 3 weeks. Levels of urine nicotine and cotinine were used as measures of exposure. Paraffin-embedded, haematoxylin and eosin (HE)-stained sections were used for examination. Morphometry of studied organs was performed using a computer image analyser. RESULTS: Applied smoke dose and exposure time produced dramatic histopathological changes in lungs of exposed rats (emphysema, emphysematous, inflammatory, metaplastic changes) and reduction in height of respiratory-bronchiole epithelium, and considerably less-marked morphological changes in hepatic (number of apoptotic hepatocytes) and renal (height of proximal convoluted tubule epithelium) cells as well as in the placenta (for example, size of giant cells in labyrinth, height of epithelium covering yolk sac ). Exposure to cigarette smoke did not result in histopathological changes in lungs and liver of surviving foetuses. The duration of pregnancy was not changed but a tendency for a decrease in the mothers' fertility indices as well as some changes in foetal and newborn parameters was observed. CONCLUSION: Taking into account the morphological changes observed in adult rat tissues and placentae which can result in definite hormonal and trophic effects on the foetus, the possibility of early or late physiological effects in progeny under the influence of cigarette smoke must be taken into consideration.

Influence of acetaminophen and trichloroethylene on liver cytochrome P450-dependent monooxygenase system.

The aim of the study was to evaluate the effect of acetaminophen (APAP) and/or trichloroethylene (TRI) on the liver cytochrome P450-dependent monooxygenase system, CYP2E1 and CYP1A2 (two important P450 isoforms), and liver glutathione (GSH) content in rats. Rats were given three different doses of APAP (250, 500 and 1000 mg/kg b...) and then the above-mentioned parameters were measured for 48 h. The lowest APAP dose produced small changes in the cytochrome P450 content of liver. At 500 mg/kg APAP increased the cytochrome P450 content to 230% of the control. The inductive effect was seen at 1000 mg/kg dose but at 24 h and later. NADPH-cytochrome P450 reductase activity was the highest after the lowest dose of APAP, while after the highest dose it was equal to the control value. TRI increased both the cytochrome P450 content and the NADPH-cytochrome P450 reductase activity. When TRI was combined with APAP, both these parameters increased in the first hours of observation, but they returned to the control values at 24 h. When APAP was given at 250 mg/kg, GSH levels decreased to 55% of the control at 8 h and returned to the control values at 24 h. The higher doses of APAP decreased GSH levels more than the lowest dose, but after 24 h GSH levels did not differ from those of the control. When TRI was given at 250 mg/kg, the GSH levels decreased to 68% of the control at 2 h and then they increased gradually and tended to exceed the control values at 48 h. The effect of TRI combined with APAP on the level of GSH was virtually the same as that of APAP alone given at 500 mg/kg.

Inhibiting effect of ethinylestradiol/levonorgestrel combination on microsomal enzymatic activities in rat liver and kidney.

The aim of the study was to evaluate the effects of two therapeutic combinations of ethinylestradiol (EE) and levonorgestrel (LE), which are used in triphasic contraceptives, on the activities of drug-metabolizing enzymes in rat liver and kidney. Sexually mature female Wistar rats were given 0.03 mg EE and 0.05 mg LE, or 0.03 mg EE and 0.125 mg LE for 6 or 18 sexual cycles, i.e. for 30 or 90 days. EE/LE inhibited not only the metabolic capacity of P450, a protein which directly undergoes suicide inhibition, but also the level of rat liver cytochrome b5 (dependent on the heme pool) as well as the activities of NADPH-cytochrome P450 reductase and NADH-cytochrome b5 reductase in the liver and kidney. The majority of these effects were independent of the gestagen dose and of the duration of treatment, suggesting that estrogen is a predominant inhibiting factor in the EE/LE combination. The study has revealed differences in the enzyme activities between the liver and kidney, which may result from the fact that these organs display different sets of P450 isoforms and, therefore, their monooxygenase systems show distinct capacities to metabolize exogenous steroids.

Effects of ethinylestradiol and levonorgestrel on morphology, ultrastructure and histoenzymatic activity of rat kidney.

Sexually mature female Wistar rats were given daily intragastric doses of ethinylestradiol (EE) and levonorgestrel (LE) used normally in women: (1) 0.03 mg EE and 0.05 mg LE; (2) 0.04 mg EE and 0.075 mg LE; (3) 0.03 mg EE and 0.125 mg LE. All groups were treated for 6 months in 5-day cycles (four-day treatment with a one-day break), i.e. for 36 sexual cycles. In rat kidneys, the activity of succinic dehydrogenase, NADPH-tetrazolium reductase, Mg(2+)-ATPase and alkaline phosphatase were decreased, while those of lactate dehydrogenase, acid phosphatase and glucose-6-phosphatase were enhanced. We have found a correlation between enzymatic changes and ultrastructural changes in epithelial renal cells. These changes may reflect: (1) inhibited oxidative processes associated with the mitochondrial and microsomal systems of electron transport; (2) a compensatory increase in anaerobic processes; (3) increased glyconeogenesis; (4) inhibited transport processes and increased cellular catabolism. The kidney cortex and medulla did not show any significant morphological changes after 6 months of treatment. The study has shown that EE/LE combinations produce histochemical and ultrastructural changes in the kidney, which are dependent on the doses of gestagens.

Effects of ethinylestradiol-norethisterone acetate combinations on the ultrastructure of liver, kidney, ovary and endometrium cells.

Sexually mature female Wistar rats were given 0.05 mg ethinylestradiol (EE) + 0.5 mg norethisterone acetate (NET), or 0.1 mg EE + 1.0 mg NET for 6 or 12 sexual cycles, i.e., for 30 or 60 days. Rat hepatocytes, renal proximal tubule cells, ovarian granulosa cells and endometrial gland cells showed ultrastructural changes that correlated with the dose and duration of EE/NET treatment. The most common ultrastructural features were as follows: reduced RER, mitochondrial damage, and an increased number of lysosomes. The study has shown that EE/NET combinations used in oral contraception produce ultrastructural lesions, which may impair protein biosynthesis and energy production processes, and may simultaneously enhance cellular catabolism.

The circadian rhythm in activity of the periodic acid Schiff reaction and of the Mg and Ca content in rat liver in relation to age and season of the year.

The experiments were carried out on male Wistar rats aged 6, 12 and 24 months, over the four seasons of the year. Analysis of the results obtained in all age groups disclosed that changes in activity of the p.a.S (periodic acid Schiff) reaction and in concentrations of Mg and Ca in the liver showed rhythmic oscillations with a period of 12 hours. The maximal p.a.S reaction activity and of Ca and Mg levels were generally found to coincide throughout all seasons and in all age groups. The rhythms of change in these parameters in 12- and 24-month-old rats showed a phase shift as compared to the 6-month-old animals.

[Effects of age and selected inductors of aromatic hydrocarbon hydroxylase (AHH) activity in the rat liver]. / Wplyw wieku i wybranych induktorów na aktywnosc watrobowej hydroksylazy weglowodorów aromatycznych (AHH) u szczurów.

The effects of treatment with phenobarbital, beta-naphthoflavone and dexamethasone on 0,5, 1, 2, 4, 8, 12, 20 and 28 month old male Wistar rats was studied. The animals were treated intraperitoneally with phenobarbital (50 mg/kg; two times), beta-naphthoflavone (20 mg/kg; three times) or dexamethasone (10 mg/kg; three times). The rats were killed and Dallner method hepatic microsomes were isolated. In this fractions the protein by Lowry method and AHH activity according to Gelboin were determined. The AHH activity changes was not observed with age. In all studied animals (with 28 months old rats) phenobarbital inhibited AHH activity. The beta-naphthoflavone markedly increased the AHH activity; particularly in sex maturation and senescent. The dexamethasone injections also increased activity of the enzyme but in young rats only.

Effect of cadmium upon the activity of some selected marker enzymes in rat liver.

The aim of this study was to determine activities of selected enzymes, i.e. Mg(++)-stimulated ATP-ase, acid phosphatase (AcP), esterase and succinate dehydrogenase (SDH) in rat liver after intragastric administration of cadmium chloride. The investigations were performed on forty male rats, Wistar strain, which made up one control group and two experimental groups. The rats of one experimental group were given a single dose of cadmium chloride solution of 88 mg CdCl2 per kg body weight (Group I), whereas the other experimental group received a double dose, i.e. 176 mg CdCl2 per kg body weight (Group II). The activities of enzymatic reactions were determined by means of analysis of surface optical density using the image computer analyzer, whereas the degree of mental accumulation was estimated with atom absorption spectrophotometry. Following cadmium chloride administration, the activities of SDH and esterase decreased in both experimental groups compared to controls. The decrease in both enzymatic activities was statistically significant. Similarly, activities of ACP and Mg(++)-stimulated ATP-ase decreased below control level in the rats of the Group I, which were given lower dose of CdCl2. This change was not statistically significant. Higher dose of CdCl2 (Group II) caused a statistically significant increase in acid phosphatase activity and only a small increase (bearing no statistical significance) in Mg(++)-stimulated ATP-ase activity. In addition, it was found that the accumulation of cadmium in both the liver and the kidneys is dose-related.

Changes of enzyme activity in the rat liver at different age in circadian cycle.

Most of the biological processes in the living organisms of both animals and man are known to be of rhythmical nature. Variability of enzymatic activity in circadian cycle depends on many factors among other on age, sexual maturity, diet as well as medication. The results obtained in our studies indicate, that the activity changes of acid phosphatase and ATP-ase Mg++ dependent in the liver of all the examined age groups were of 24 hour circadian rythm. As to the acid phosphatase activity the results of this experiments showed that in circadian cycle in all examined age groups there is only one peak of elevated activity. ATP-ase Mg++ dependent showed two activity peaks appearing at the same hour both in 30 and 60 days old animals. It should be noticed that the activities of ATP-ase Mg++ dependent in 100 day old animals were two times higher than in 30 and 60 days old rats.