Acute toxicity of sodium arsenite in a complex food matrix.

Acute toxicity of a single oral dose of sodium arsenite (As), administered in half and half cream (HH), was assessed in male and non-pregnant female rats (0.41, 4.1, 41.0 and 410.0mg/kg body weight) and pregnant rats (0.41, 4.1 and 41.0mg/kg body weight). Control rats received deionized water alone, HH alone or 41.0mg/kg As in deionized water (41 mg/kg As-water). Male and non-pregnant rats were monitored for 14 consecutive days post-dosing. Pregnant rats, dosed on gestation day 10 (GD-10), were monitored until fetuses were collected on GD 20. High mortality (100%) was observed in male and non-pregnant female rats exposed to 410.0mg/kg As-HH. Low mortality (25%) was observed in non-pregnant female rats exposed to 41 mg/kg As-water. No mortality was observed in other control or treated groups. Reduced female fetal numbers were observed in the 41 mg/kg As-water group but not in the other control groups. Developmental effects were not observed in the controls or the As-HH treatment groups. In conclusion, As toxicity was not reduced when a high dose (410 mg/kg) was administered in HH however, at lower doses (41 mg/kg), HH reduced acute As oral toxicity in the female and developing fetus.

Effects of oral androstenedione on phospholipid fatty acids, ATP, caspase-3, prostaglandin E(2) and C-reactive protein in serum and livers of pregnant and non-pregnant female rats.

Androstenedione, a steroidal dietary supplement taken to enhance athletic performance, could affect serum and liver lipid metabolism, induce liver toxicity or alter inflammatory response depending on dose and duration of exposure. Pregnancy could further exaggerate these effects. To examine this, mature female rats were gavaged with 0, 5, 30 or 60 mg/kg/day androstenedione beginning two weeks prior to mating and continuing through gestation day 19. Non-pregnant female rats were gavaged over the same time frame with 0 or 60 mg/kg/day androstenedione. Serum was collected and livers were removed from dams on gestation day 20 and from non-pregnant rats after 5 weeks of treatment. Androstenedione had no effect on serum total cholesterol, triglycerides or HDL-cholesterol, but significantly decreased C-reactive protein in pregnant rats and prostaglandin E(2) in serum of both pregnant and non-pregnant rats. There were treatment related decreases in liver ATP and, to a lesser degree, caspase-3 and no change in alkaline phosphatase of pregnant female rats. Androstenedione decreased docosahexaenoic acid in both serum and liver phospholipids of pregnant female rats. In conclusion, oral androstenedione did not result in overt hepatotoxicity in pregnant female rats, but produced modest changes in lipid metabolism and may impair regeneration of injured hepatic cells or tissue.

Effects of oral androstenedione on steroid metabolism in liver of pregnant and non-pregnant female rats.

It is unknown whether androstenedione, a steroidal dietary supplement taken to enhance athletic performance, can affect physiological hormone levels by altering liver enzyme activities that metabolize steroid hormones. Altered hormone levels could be especially devastating during pregnancy. Mature female rats were gavaged with 0, 5, 30 or 60 mg/kg/day androstenedione beginning two weeks prior to mating and continuing through gestation day 19. Non-pregnant female rats were gavaged over the same time frame with 0 or 60 mg/kg/day androstenedione. Livers were removed from dams on gestation day 20 and from non-pregnant rats after five weeks' treatment. Liver microsomes were incubated with 200 microM testosterone, and the reaction products were isolated and analyzed by HPLC. In pregnant rats, formation of 6alpha-, 15beta-, 7alpha-, 16beta-, and 2beta-hydroxytestosterone was increased significantly vs. control at the highest dose level only. Formation of 6beta-hydroxytestosterone increased significantly at both the 30 and 60 mg/kg/day dose levels. In non-pregnant rats, 60 mg/kg/day androstenedione significantly increased formation of 15beta-, 6beta-, 16beta-, and 2beta-hydroxytestosterone. The data suggest that high oral doses of androstenedione can induce some female rat liver cytochromes P450 that metabolize steroid hormones and that the response to androstenedione does not differ between pregnant and non-pregnant female rats.

Teratological research using in vitro systems. V. Nonmammalian model systems.

In this review of alternative tests to whole-animal rodent studies, the use of sub-mammalian and sub-vertebrate systems is investigated. The history, methodology, known limitations, end points, dose response, and requirements of virus, hydra, planarian, cricket, fish, amphibia, Drosophila, and chicken embryo systems are discussed.

An overview of rodent toxicities: liver and kidney effects of fumonisins and Fusarium moniliforme.

Fumonisins are produced by Fusarium moniliforme F. verticillioides) and other Fusarium that grow on corn worldwide. They cause fatal toxicoses of horses and swine. Their effects in humans are unclear, but epidemiologic evidence suggests that consumption of fumonisin-contaminated corn contributes to human esophageal cancer in southern Africa and China. Much has been learned from rodent studies about fumonisin B1(FB1), the most common homologue. FB1 is poorly absorbed and rapidly eliminated in feces. Minor amounts are retained in liver and kidneys. Unlike other mycotoxins, fumonisins cause the same liver cancer promotion and subchronic (studies (3/4) 90 days) liver and kidney effects as (italic)F. moniliforme. FB 1 induces apoptosis of hepatocytes and of proximal tubule epithelial cells. More advanced lesions in both organs are characterized by simultaneous cell loss (apoptosis and necrosis) and proliferation (mitosis). Microscopic and other findings suggest that an imbalance between cell loss and replacement develops, a condition favorable for carcinogenesis. On the molecular level, fumonisins inhibit ceramide synthase, and disrupt sphingolipid metabolism and, theoretically, sphingolipid-mediated regulatory processes that influence apoptosis and mitosis. Liver sphingolipid effects and toxicity are correlated, and ceramide synthase inhibition occurs in liver and kidney at doses below their respective no-observed-effect levels. FB1 does not cross the placenta and is not teratogenic in vivoin rats, mice, or rabbits, but is embryotoxic at high, maternally toxic doses. These data have contributed to preliminary risk evaluation and to protocol development for carcinogenicity and chronic toxicity studies of FB1 in rats and mice.

Study of the teratogenic potential of FD & C Yellow No. 5 when given by gavage to rats.

FD & C Yellow No. 5 (tartrazine) was given to Osborne-Mendel rats by gavage at dose levels of 0, 60, 100, 200, 400, 600 or 1000 mg/kg body weight/day on days 0-19 of gestation. No maternal or developmental toxicity was observed when the rats were killed on day 20. The mean daily food consumption for the entire period of gestation was significantly greater in the females given 1000 mg/kg body weight/day than in the controls, but maternal body-weight gain was not affected. No dose-related effects were observed in implantations, foetal viability or external foetal development. Foetal skeletal and visceral development was similar among foetuses from all groups. At the doses given, FD & C Yellow No. 5 was neither toxic nor teratogenic.

A study of the teratogenic potential of caffeine ingested in drinking-water.

Caffeine dissolved in drinking-water was available ad lib. to Osborne-Mendel rats at dose levels of 0, 0.007, 0.018, 0.036, 0.07, 0.10, 0.15 or 0.20% during days 0-20 of gestation. The corresponding daily caffeine intakes were 0, 10.1, 27.4, 50.7, 86.6, 115.8, 160.9 and 204.5 mg/kg body weight. Dosages of 160.9 and 204.5 mg/kg were associated with decreased implantation efficiency, increased resorptions and decreased mean numbers of viable foetuses. Numbers of runts were significantly increased after dosages of 115.8-204.5 mg/kg/day. Foetal body weight and length were decreased and oedematous foetuses were increased at dosages of 86.6-204.5 mg/kg/day. Contrary to results seen after gavage studies, caffeine available ad lib. in drinking-water produced no dose-related gross anomalies. Only two animals with missing or hypoplastic nails were produced, both in the 160.9-mg/kg group. Sternebral ossification deficiencies were increased at all dose levels except 10.1 mg/kg/day. Skeletal ossification deficiencies were increased in a dose-related manner at the four highest dose levels. Caffeine given by water bottle produced ossification deficiencies similar to those seen after intubation, but at higher dosages.

Potential reversibility of skeletal effects in rats exposed in utero to caffeine.

Groups of Osborne-Mendel rats, killed at three time intervals following mating, were studied to determine whether prenatal skeletal ossification delays observed following low-level caffeine administration represent transient or persistent ossification problems. Group A litters were killed on gestation day 20; group B neonates were killed on post-natal day 0; and group C pups were killed on post-natal day 6. Within each group, dose levels of 0, 0.018, 0.036 or 0.07% caffeine in distilled water were available ad lib. to groups of 30-60 dams from gestation day 0 to day 20. Average daily caffeine consumption was 24.7-29.0 mg/kg body weight for the 0.018% group, 42.7-48.8 mg/kg body weight for the 0.036% group and 70.6-75.1 mg/kg body weight for the 0.07% group. In group A litters, the mean number of viable foetuses was significantly less in the mid-dose and high-dose animals than in the controls. In the same group, the average number of foetuses per litter with at least one sternebral ossification delay was increased significantly in all treated groups and the average number of foetuses per litter with at least two sternebral variations was significantly increased in the mid- and high-dose groups. The percentages of litters containing foetuses with at least two and at least three sternebral variations and the average number of foetuses per litter with at least three sternebral variations were significantly increased only in the high-dose group. Foetuses from the mid- and high-dose groups also had significant increases in certain skeletal defects, namely missing centra and reduced ossification of the dorsal arch. Foetuses from the high-dose group also had significant increases in bipartite supraoccipital, and reduced ossification of the hyoid, metacarpals and metatarsals. In group B, day 0 neonates from all treated groups showed a significantly increased incidence of delayed sternebral ossification (average number of foetuses per litter with one or more missing, incomplete or bipartite sternebrae). The percentages of litters containing neonates with delayed sternebral ossification were also increased significantly in all treated groups. Neonates from the 0.07% level in group B also exhibited a significant increase in the incidence of supernumerary rib bud, and in reduced ossification of the metacarpals, metatarsals and calcaneus bones. Significant increases were also seen, in group B, in the low- and mid-dose animals, respectively, in supernumery rib bud and in reduced ossification of the metatarsals.(ABSTRACT TRUNCATED AT 400 WORDS)

Study of the teratogenic potential of guar gum.

Guar gum in the diet at 0, 1, 2, 4, 7.5 or 15% was available ad lib. to male and female Osborne-Mendel rats for 13 wk before mating, during mating and throughout gestation. During gestation, the females consumed 0, 0.7, 1.4, 2.7, 5.2 or 11.8 g guar gum/kg of body weight/day, respectively. The animals were killed on gestation day 20. No behavioural effects were seen in any of the treated dams, and no females died during the experiment. Pregnant females in the treated groups consumed less food than the controls during gestation days 0-20 but the decrease was significant only in the 4 and 7.5% groups and was not dose related. Ingestion of guar gum before mating did not affect fertility. In the dams fed 1-7.5% guar gum, there was no effect on the number of corpora lutea or implantations. The dams fed 15% guar gum had slightly fewer corpora lutea and implantations than the controls but no effect was seen on implantation efficiency in this group. The number of viable foetuses/litter was also reduced slightly but not significantly in the 15% group, but since the number of resorptions was not affected, this decrease appears to be an effect of the decreased number of corpora lutea. There was no compound-related effect on foetal development or sex distribution. No terata were seen.

Study of the teratogenic potential of gum arabic.

Gum arabic in the diet at 0, 1, 2, 4, 7.5 or 15% was available ad lib. to male and female Osborne-Mendel rats during premating and mating and throughout gestation. During gestation, the treated females consumed from 683 mg gum/kg body weight/day in the 1% group to 10,647 mg gum/kg/day in the 15% group. The animals were killed on gestation day 20. There were no dose-related changes in maternal findings, number of foetuses, foetal viability or external, visceral or skeletal variations. No terata were seen.

Study of the teratogenic potential of FD & C Red No. 40 when given by gavage to rats.

Osborne-Mendel rats were intubated with FD & C Red No. 40 at dose levels of 0, 30, 75, 150, 300, 600, or 1000 mg/kg body weight/day on days 0-19 of gestation. No developmental toxicity was observed when the animals were killed on day 20 of gestation. No dose-related changes were seen in maternal daily observations, food consumption, body-weight gain or implantations, or in foetal viability, body weight, body length, sex distribution or external variations. Skeletal and soft-tissue development appeared similar in foetuses of all groups. The isolated increases that occurred in the number of male foetuses, number of females with two or more resorptions, number of litters with three or more sternebral variations and incidence of 14th rib bud are considered random occurrences and were not related to dosage.

Study of the teratogenic potential of FD & C yellow No. 5 when given in drinking-water.

FD & C Yellow No. 5 was available to pregnant Osborne-Mendel rats throughout gestation at dose levels of 0.05, 0.1, 0.2, 0.4 or 0.7% in solution in distilled drinking-water. Based on fluid consumption, the rats received 67.4, 131.8, 292.4, 567.9 and 1064.3 mg FD & C Yellow No. 5/kg body weight/day. Distilled water served as the control. No dose-related changes were seen in mean daily food consumption or maternal body-weight gain. Starting during the second trimester of gestation, fluid consumption was significantly greater in the rats given 0.7% FD & C Yellow No. 5 than in the controls. The females were killed on gestation day 20. No dose-related changes were seen in maternal clinical findings, implantations, foetal viability or foetal size (weight and length). No dose-related foetal terata were seen. Neither visceral development nor skeletal development (sternebral and other skeletal bones) was affected by the dye. The small numbers of statistically significant increases in skeletal variations in the 0.05 and 0.4% levels are considered random because they are not dose related.

Teratogenic potential of FD & C red no. 3 when given in drinking water.

FD & C Red No. 3 (erythrosine), a commonly used food additive, was administered to pregnant Osborne-Mendel rats to study its teratogenic potential. Dosing solutions of 0.05, 0.1, 0.2 or 0.4% in distilled water were available at all times and corresponded to daily doses of 64, 121, 248 and 472 mg FD & C Red No. 3/kg body weight. Distilled water served as the control. On gestation day 20, the animals were killed and caesarean sections were performed. The treated animals consumed less fluid than did the control animals, but only random decreases were statistically significant and no dose relationship was seen. Only the 0.2% group consumed significantly more feed than the controls during gestation. Maternal weight gain during days 0-20 was not significantly affected in any group. No dose-related changes were seen in maternal clinical findings, implantations, foetal viability, foetal size (weight and length) or visceral development. No dose-related teratogenesis was seen. Skeletal development was not affected; the few statistically significant increases in skeletal variations were not dose related and were considered to be random. FD & C Red No. 3 was neither foetotoxic nor teratogenic at the dose levels tested in drinking water.

Effect of intratesticular injection of sodium fluoride on spermatogenesis.

The potential of sodium fluoride to affect spermatogenesis in the rat was assessed by intratesticular injection. Experimental rats' left testis was injected with sodium fluoride (50, 175 and 250 ppm) in vehicle (0.9% physiological saline); control testes were injected with vehicle. The right testis served as a non-injected control. Testicular tissues collected 'at' and 'distal to' the injection site and from the non-injected control testes were evaluated microscopically 24 hr and 1, 2 and 3 wk post-injection. Testicular tissues obtained at and distal to the injection site in all fluoride-injected groups resembled tissues collected from corresponding areas in the controls. Seminiferous tubule damage observed in both the vehicle-injected control testes and the fluoride-injected testes but not in the non-injected testes was attributed to injection trauma. Polymorphonuclear leucocyte infiltration was observed 24 hr post injection only at the injection site in the vehicle- and fluoride-injected groups. Leydig cells were unaffected. Leucocyte infiltration with seminiferous tubule damage was not considered to be a fluoride treatment-related effect because it was observed in both vehicle- and fluoride-injected testes. The results demonstrate that the rat is not adversely affected by direct exposure to fluoride at levels 200 times greater than those under normal conditions.

Teratogenic potential of purified pentachlorophenol and pentachloroanisole in subchronically exposed Sprague-Dawley rats.

Male and female Sprague-Dawley (Spartan) rats were exposed to dietary levels of 0, 60, 200 or 600 ppm purified pentachlorophenol (PCP) or pentachloroanisole (PCA) for 181 days, through mating and pregnancy. The daily intakes of PCP were 0, 4, 13 or 43 mg/kg body weight and of PCA were 0, 4, 12 or 41 mg/kg body weight. Animals exposed to PCP generally consumed more food than control animals during pregnancy. Dams at the high-dose level of both compounds showed evidence of toxicity, weighing less on day 0 of gestation and gaining less throughout pregnancy than did the controls. Dams exposed to the high dose of PCP gained less weight during pregnancy (exclusive of the gravid uterus) than control dams. At the 43 mg/kg/day dose level PCP was embryolethal. Foetuses at the lower dose levels of PCP exhibited dose-related decreases in body weights. A reduction in crown-rump length and an increase in foetal skeletal variations were seen at 13 mg/kg/day in PCP animals only. An intake of 41 mg PCA/kg/day was associated with a decrease in the number of corpora lutea and in embryolethality. PCA exposure also resulted in reductions in foetal body weight and crown-rump lengths of males at 4 and 41 mg/kg/day. Female foetuses were unaffected.

Testing the potential of sodium fluoride to affect spermatogenesis: a morphometric study.

This study provides quantitative information on the effect of sodium fluoride (NaF) on the testes of F1 generation male rats exposed in utero and during lactation to NaF at one of four concentrations (25, 100, 175, 250 ppm). At weaning, the F1 generation males were exposed to NaF in their drinking water for 14 weeks, after which time testicular tissues were perfusion-fixed with glutaraldehyde and observed after being embedded in plastic. The seminiferous tubules comprised 89%, 87%, 88%, 88% and 88% of the total testis volume while the interstitial space occupied 9.3%, 11.2%, 10.2%, 9.8% and 9.9% of the total testis volume for the 0, 25, 100, 175 and 250 ppm NaF treatment groups, respectively. Statistically significant differences between control and NaF-treated rats were not observed with respect to absolute volume of the seminiferous tubules, interstitial space, Leydig cells, blood vessels boundary layer, lymphatic space, macrophages, tubular lumen or absolute tubular length and absolute tubular surface area, mean Sertoli cell nucleoli number per tubular cross-section, mean seminiferous tubule diameter and the mean height of the seminiferous epithelium. A statistically significant decrease in the absolute volume and volume percent of the lymphatic endothelium was observed in the 175 and 250 ppm NaF-treated groups and in the testicular capsule in the 100 ppm NaF-treated groups. The significance of this finding is unknown at the present time. Overall, the quantitative information obtained suggests that exposure to NaF at the doses used in the present study does not adversely affect testis structure or spermatogenesis in the rat.

Testing the potential of flaxseed to affect spermatogenesis: morphometry.

Quantitative information was collected on male reproductive effects of maternal and postnatal dietary exposure to flaxseed (20 or 40%), flaxmeal (13 or 26%) or standard NIH AIN-93 feed (0% flaxseed control). Measurements were made on the testes of F1 generation males rats (1) whose mothers were exposed to the diets designated above, and (2) who, after weaning, were placed on the same diet as their mothers for an additional 70 days. The seminiferous tubules comprised 86%, 84%, 84%, 84% and 85% of the total testis volume while the interstitial space comprised 12%, 14%, 14%, 14%, 13% of the total testis volume for the 0% flaxseed/flaxmeal, 20% flaxseed, 13% flaxmeal, 40% flaxseed and 26% flaxmeal groups, respectively. Statistically significant decreases in the absolute volume of the seminiferous tubules were observed in the 20% and 40% flaxseed-treated groups when these groups were compared to controls. Borderline statistically significant differences were also observed when Sertoli cell nucleolar number per tubular cross-section were compared in the 13% flaxmeal and 20% flaxseed treatment groups. These effects were not considered biologically significant because other parameters of male reproductive function appeared normal. Overall, the quantitative information obtained suggests that exposure to flaxseed/flaxmeal at the doses used in the present study does not adversely affect testis structure or spermatogenesis in the rat.

Mineral interactions in rats fed AIN-76A diets with excess calcium.

The effects of moderate increases in dietary calcium on maternal and foetal mineral interactions were studied in Charles River CD/VAF Plus rats. Female rats were given 0.50, 0.75, 1.00 or 1.25% dietary calcium as calcium carbonate in AIN-76A diets for 6 wk before mating, during mating and for 20 days of gestation. Inductively coupled argon plasma-atomic emission spectrometry was used to determine mineral levels in the tissues of non-pregnant rats after 42 days on the diets, in the tissues of pregnant rats on day 20 of gestation and in the whole body of day-20 foetuses. The femurs of the non-pregnant and pregnant rats had a dose-related linear increase in calcium content. In livers of the non-pregnant rats, dose-related linear increases in the phosphorus, zinc and magnesium content were observed, but there was a dose-related decrease in the iron content. There were dose-related linear decreases in the iron and copper contents of the kidneys from the non-pregnant rats. In pregnant rats dose-related linear decreases were observed in the iron content of the liver and in the zinc, iron and magnesium contents of the kidney. The foetuses from rats given a moderate increase in dietary calcium had dose-related decreases in the whole-body contents of phosphorus, iron, copper and magnesium.

Testing the potential of sodium fluoride to affect spermatogenesis in the rat.

The potential of sodium fluoride (NaF) to affect spermatogenesis and endocrine function was assessed in P and F1 generation male rats. Male and female experimental rats received sodium fluoride in their drinking water at one of four concentrations (25, 100, 175, 250 ppm). P generation male and female rats were exposed to sodium fluoride in their drinking water for 10 wk and then males were mated to females within the same treatment groups. Reproductive tissues were collected from P generation male rats after approximately 14 wk of treatment. Pregnant females (P) were exposed to sodium fluoride via their drinking water through gestation and lactation. F1 generation weanling male rats remained within the same treatment groups as their parents. F1 generation male rats were exposed to sodium fluoride in their drinking water for 14 wk, at which time reproductive tissues were collected. Dose-related effects were not observed within the P and F1 treatment groups in testis weights, prostate/seminal vesicle weights, non-reproductive organ weights, testicular spermatid counts, sperm production per gram of testis per day, sperm production per gram of testis, LH, FSH or serum testosterone concentrations. Histological changes were not observed in testicular tissues from either the P or F1 generation. We conclude that prolonged exposure to sodium fluoride in drinking water at the doses administered in this study does not adversely affect spermatogenesis or endocrine function in the P and F1 generation male rats.

The effect of maternal exposure to flaxseed on spermatogenesis in F(1) generation rats.

Pregnant Sprague-Dawley rats were exposed to a flaxseed (20 or 40%), flaxmeal (13 or 26%) or standard NIH AIN-93 (0% flaxseed control) diet throughout gestation and until their offspring were weaned. After weaning, F(1) generation males were placed in the same diet treatment groups as their mothers for 70 days. Statistically significant differences were not observed between either low-dose or high-dose flaxseed and flaxmeal-treated animals and the 0% flaxseed control animals for testis weights, homogenization resistant spermatid counts, daily sperm production rates, epididymal weights, seminal vesicle weights, seminiferous tubule fluid testosterone concentrations and the percentage of sperm abnormalities. The following statistically significant differences were observed when treated groups and the 0% flaxseed control groups were compared: (1) increases in serum LH in the 20% and 40% flaxseed treatment groups and in serum LH and testosterone in the 26% flaxmeal treatment group; (2) increases in the cauda epididymal weight from the 20% and 40% flaxseed groups; (3) increases in cauda epididymal sperm numbers/g epididymis from the 20% and 40% flaxseed and the 13% and 26% flaxmeal treatment groups; (4) a decrease in prostatic weight from the 20% flaxseed and 13% and 26% flaxmeal treatment groups. Prostate weight in the 40% flaxseed treatment group was lower but not statistically significantly different than the 0% flaxseed control group. Histological effects on spermatogenesis were not observed in either the control group, flaxmeal or the flaxseed treated groups.