Comparative sub-chronic toxicity studies in rats of two indistinguishable herbal plants, Cynanchum wilfordii (Maxim.) Hemsley and Cynanchum auriculatum Royle ex Wight.

Sub-chronic toxicity studies using rats have been conducted for Cynanchum wilfordii (Maxim.) Hemsley (CW) and Cynanchum auriculatum Royle ex Wight (CA). CW water extract didn't show any adverse effects whereas administering CW powder decreased body weights in complication with decreased food consumptions. In the case of CA water extract, triglyceride and absolute/relative liver weights were elevated and vacuolation was observed in liver. Treated CA powder in male rats increased alanine aminotransferase and aspartate aminotransferase and induced single cell necrosis and multinucleated hepatocyte in liver. As for female rats, increased absolute/relative weights and hypertrophy/vacuolation in adrenal glands and vacuolation in ovaries were observed when administered CA powder. In conclusion, no observed adverse effect level (NOAEL) of CW water extract was over 5000 mg/kg/day, while NOAEL of CW powder was 700 mg/kg/day for female and 150 mg/kg/day for male. In case of CA, NOAEL of water extract was 1500 mg/kg/day for male and 2000 mg/kg/day for female, while NOAEL of powder was 150 mg/kg/day for both gender. To the best of our knowledge, this is the first sub-chronic toxicity study on the adverse effects, target organs and its dose levels of C. wilfordii (Maxim.) Hemsley and C. auriculatum Royle ex Wight following GLP protocols.

Subchronic toxicity study of Coptidis rhizoma in rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Coptidis Rhizoma (CR) is a medical herb from the family Ranunculacease that has been used to treat gastroenteritis, dysentery, diabetes mellitus, and severe skin diseases. AIM OF THE STUDY: To evaluate the no-observed-adverse-effect level (NOAEL) and the toxicity of CR, following repeat oral administration to rats for 13 weeks. MATERIALS AND METHODS: CR was administered by oral gavage to groups of rats (n=10/group, each sex) at dose levels of 0 (control), 25, 74, 222, 667 or 2000 mg/kg/day 5 times per week for 13 weeks. Mortality, clinical signs, body weights, food consumption, hematology, serum chemistry, urinalysis, vaginal cytology and sperm morphology, organ weights, gross and histopathological findings were compared between control and CR groups. RESULTS: Urinalysis showed a significant increase in N-acety1-ß-glucosaminidase in males in the 2000 mg/kg/day group (P<0.01). However, no mortality or remarkable clinical signs were observed during this 13-week study. No adverse effects on body weight, food consumption, hematology, serum chemistry, organ weights, gross lesion, histopathology, vaginal cytology, sperm motility, or deformity were observed in the males or female rats treated with CR. CONCLUSIONS: On the basis of these results, the NOAEL of CR is determined to be 667 mg/kg/day for males and 2000 mg/kg/day for females.

Subchronic oral toxicity of evodia fruit powder in rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Evodia, a fruit from Evodia rutaecarpa, has been used in oriental medicine, and since its various pharmaceutical actions, including anti-cancer activity, have become known, evodia has been widely used as a dietary supplement. However, information regarding its toxicity is limited. MATERIALS AND METHODS: Evodia fruit from Evodia rutaecarpa (Juss.) Benth. var. officinalis (Dode) Huang (0, 25, 74, 222, 667, and 2000 mg/kg) was administered orally five times per week for 13 weeks. Clinical signs, body weight, food consumption, hematology, serum chemistry, urinalysis, vaginal cytology, sperm morphology, organ weight, and gross and histopathological findings were evaluated. RESULTS: Urinary ketone body excretion was detected in males at 667 and 2000 mg/kg and in females at 2000 mg/kg. An increase in absolute/relative liver weight was observed in both sexes at 2000 mg/kg. Although levels of serum alanine aminotransferase, glucose, total cholesterol, and triglycerides were significantly reduced in males and/or females at 200 and/or 667 and 2000 mg/kg, all values were within normal ranges and were considered non-adverse. In addition, no treatment-related differences in body weight, food consumption, hematology, vaginal cytology, sperm morphology, or gross and histopathological examination were detected. CONCLUSIONS: The subchronic no-observable-adverse-effect level for evodia fruit powder following oral administration in rats is greater than 2000 mg/kg.

A 90-day study of subchronic oral toxicity of 20 nm, negatively charged zinc oxide nanoparticles in Sprague Dawley rats.

PURPOSE: The widespread use of nanoparticles (NPs) in industrial and biomedical applications has prompted growing concern regarding their potential toxicity and impact on human health. This study therefore investigated the subchronic, systemic oral toxicity and no-observed-adverse-effect level (NOAEL) of 20 nm, negatively charged zinc oxide (ZnO(SM20(-))) NPs in Sprague Dawley rats for 90 days. METHODS: The high-dose NP level was set at 500 mg/kg of bodyweight, and the mid- and low-dose levels were set at 250 and 125 mg/kg, respectively. The rats were observed during a 14-day recovery period after the last NP administration for the persistence or reduction of any adverse effects. Toxicokinetic and distribution studies were also conducted to determine the systemic distribution of the NPs. RESULTS: No rats died during the test period. However, ZnO(SM20(-)) NPs (500 mg/kg) induced changes in the levels of anemia-related factors, prompted acinar cell apoptosis and ductular hyperplasia, stimulated periductular lymphoid cell infiltration and excessive salivation, and increased the numbers of regenerative acinar cells in the pancreas. In addition, stomach lesions were seen at 125, 250, and 500 mg/kg, and retinal atrophy was observed at 250 and 500 mg/kg. The Zn concentration was dose-dependently increased in the liver, kidney, intestines, and plasma, but not in other organs investigated. CONCLUSION: A ZnO(SM20(-)) NP NOAEL could not be established from the current results, but the lowest-observed-adverse-effect level was 125 mg/kg. Furthermore, the NPs were associated with a number of undesirable systemic actions. Thus, their use in humans must be approached with caution.

A 90-day study of sub-chronic oral toxicity of 20 nm positively charged zinc oxide nanoparticles in Sprague Dawley rats.

PURPOSE: The study reported here was conducted to determine the systemic oral toxicity and to find the no-observed-adverse-effect level of 20 nm positively charged zinc oxide (ZnO(SM20(+))) nanoparticles in Sprague Dawley rats for 90 days. METHODS: For the 90-day toxicity study, the high dose was set as 500 mg per kg of body weight (mg/kg) and the middle and low dose were set to 250 mg/kg and 125 mg/kg, respectively. The rats were held for a 14-day recovery period after the last administration, to observe for the persistence or reduction of any toxic effects. A distributional study was also carried out for the systemic distribution of ZnO(SM20(+)) NPs. RESULTS: No rats died during the test period. There were no significant clinical changes due to the test article during the experimental period in functional assessment, body weight, food and water consumption, ophthalmological testing, urine analysis, necropsy findings, or organ weights, but salivation was observed immediately after administration in both sexes. The total red blood cell count was increased, and hematocrit, albumin, mean cell volume, mean cell hemoglobin, and mean cell hemoglobin concentration were decreased significantly compared with control in both 500 mg/kg groups. Total protein and albumin levels were decreased significantly in both sexes in the 250 and 500 mg/kg groups. Histopathological studies revealed acinar cell apoptosis in the pancreas, inflammation and edema in stomach mucosa, and retinal atrophy of the eye in the 500 mg/kg group. CONCLUSION: There were significant parameter changes in terms of anemia in the hematological and blood chemical analyses in the 250 and 500 mg/kg groups. The significant toxic change was observed to be below 125 mg/kg, so the no-observed-adverse-effect level was not determined, but the lowest-observed-adverse-effect level was considered to be 125 mg/kg in both sexes and the target organs were found to be the pancreas, eye, and stomach.

Prenatal development toxicity study of zinc oxide nanoparticles in rats.

This study investigated the potential adverse effects of zinc oxide nanoparticles ([ZnO(SM20(+)) NPs] zinc oxide nanoparticles, positively charged, 20 nm) on pregnant dams and embryo-fetal development after maternal exposure over the period of gestational days 5-19 with Sprague-Dawley rats. ZnO(SM20(+)) NPs were administered to pregnant rats by gavage at 0, 100, 200, and 400 mg/kg/day. All dams were subjected to a cesarean section on gestational day 20, and all of the fetuses were examined for external, visceral, and skeletal alterations. Toxicity in the dams manifested as significantly decreased body weight after administration of 400 mg/kg/day NPs; reduced food consumption after administration of 200 and 400 mg/kg/day NPs; and decreased liver weight and increased adrenal glands weight after administration of 400 mg/kg/day NPs. However, no treatment-related difference in: number of corpora lutea; number of implantation sites; implantation rate (%); resorption; dead fetuses; litter size; fetal deaths and placental weights; and sex ratio were observed between the groups. On the other hand, significant decreases between treatment groups and controls were seen for fetal weights after administration of 400 mg/kg/day NPs. Morphological examinations of the fetuses demonstrated significant differences in incidences of abnormalities in the group administered 400mg/kg/day. Meanwhile, no significant difference was found in the Zn content of fetal tissue between the control and high-dose groups. These results showed that oral doses for the study with 15-days repeated of ZnO(SM20(+)) NPs were maternotoxic in the 200 mg/kg/day group, and embryotoxic in the 400 mg/kg/day group.

Rat pancreatitis produced by 13-week administration of zinc oxide nanoparticles: biopersistence of nanoparticles and possible solutions.

Zinc oxide (ZnO) nanoparticles (NPs) are used in diverse applications ranging from paints and cosmetics to biomedicine and food. Although micron-sized ZnO is a traditional food supplement, ZnO NPs are an unknown public health risk because of their unique physicochemical properties. Herein, we studied the 13-week subchronic toxicity of ZnO NPs administered via the oral route according to Organization for Economic Cooperation and Development (OECD) test guideline 408. Well-dispersed ZnO NPs were administered to Sprague-Dawley (SD) rats (11/sex/group) at doses of 67.1, 134.2, 268.4 or 536.8 mg kg(-1) per body weight over a 13-week period. The mean body weight gain in males given 536.8 mg kg(-1) ZnO NPs was significantly lower than that of control male rats, whereas no significant differences were observed between the other treatment groups and the controls. Male and female rats dosed at 536.8 mg kg(-1) ZnO NPs had significant changes in anemia-related hematologic parameters. Mild to moderate pancreatitis also developed in both sexes dosed at 536.8 mg kg(-1) , whereas no histological changes were observed in the other treatment groups. To evaluate the mechanism of toxicity, we performed a bio-persistence study and evaluated the effects of the ZnO NPs on cell proliferation. The treatment of a human gastric adenocarcinoma cell line with ZnO NPs resulted in a significant inhibition of cellular proliferation. The anti-proliferative effect of ZnO NPs or Zn(2+) was effectively blocked by treatment with chelators. These results indicate that the bio-persistence of ZnO NPs after ingestion is key to their toxicity; the no-observed-adverse effect level (NOAEL) of ZnO NPs was found to be 268.4 mg kg(-1) per day for both sexes.

Subchronic inhalation toxicity of gold nanoparticles.

BACKGROUND: Gold nanoparticles are widely used in consumer products, including cosmetics, food packaging, beverages, toothpaste, automobiles, and lubricants. With this increase in consumer products containing gold nanoparticles, the potential for worker exposure to gold nanoparticles will also increase. Only a few studies have produced data on the in vivo toxicology of gold nanoparticles, meaning that the absorption, distribution, metabolism, and excretion (ADME) of gold nanoparticles remain unclear. RESULTS: The toxicity of gold nanoparticles was studied in Sprague Dawley rats by inhalation. Seven-week-old rats, weighing approximately 200 g (males) and 145 g (females), were divided into 4 groups (10 rats in each group): fresh-air control, low-dose (2.36 × 104 particle/cm3, 0.04 µg/m3), middle-dose (2.36 × 105 particle/cm3, 0.38 µg/m3), and high-dose (1.85 × 106 particle/cm3, 20.02 µg/m3). The animals were exposed to gold nanoparticles (average diameter 4-5 nm) for 6 hours/day, 5 days/week, for 90-days in a whole-body inhalation chamber. In addition to mortality and clinical observations, body weight, food consumption, and lung function were recorded weekly. At the end of the study, the rats were subjected to a full necropsy, blood samples were collected for hematology and clinical chemistry tests, and organ weights were measured. Cellular differential counts and cytotoxicity measurements, such as albumin, lactate dehydrogenase (LDH), and total protein were also monitored in a cellular bronchoalveolar lavage (BAL) fluid. Among lung function test measurements, tidal volume and minute volume showed a tendency to decrease comparing control and dose groups during the 90-days of exposure. Although no statistically significant differences were found in cellular differential counts, histopathologic examination showed minimal alveoli, an inflammatory infiltrate with a mixed cell type, and increased macrophages in the high-dose rats. Tissue distribution of gold nanoparticles showed a dose-dependent accumulation of gold in only lungs and kidneys with a gender-related difference in gold nanoparticles content in kidneys. CONCLUSIONS: Lungs were the only organ in which there were dose-related changes in both male and female rats. Changes observed in lung histopathology and function in high-dose animals indicate that the highest concentration (20 µg/m3) is a LOAEL and the middle concentration (0.38 µg/m3) is a NOAEL for this study.

Subchronic inhalation toxicity of silver nanoparticles.

The subchronic inhalation toxicity of silver nanoparticles was studied in Sprague-Dawley rats. Eight-week-old rats, weighing approximately 253.2 g (males) and 162.6 g (females), were divided into four groups (10 rats in each group): fresh-air control, low dose (0.6 x 10(6) particle/cm(3), 49 microg/m(3)), middle dose (1.4 x 10(6) particle/cm(3), 133 microg/m(3)), and high dose (3.0 x 10(6) particle/cm(3), 515 microg/m(3)). The animals were exposed to silver nanoparticles (average diameter 18-19 nm) for 6 h/day, 5 days/week, for 13 weeks in a whole-body inhalation chamber. In addition to mortality and clinical observations, body weight, food consumption, and pulmonary function tests were recorded weekly. At the end of the study, the rats were subjected to a full necropsy, blood samples were collected for hematology and clinical chemistry tests, and the organ weights were measured. Bile-duct hyperplasia in the liver increased dose dependently in both the male and female rats. Histopathological examinations indicated dose-dependent increases in lesions related to silver nanoparticle exposure, including mixed inflammatory cell infiltrate, chronic alveolar inflammation, and small granulomatous lesions. Target organs for silver nanoparticles were considered to be the lungs and liver in the male and female rats. No observable adverse effect level of 100 microg/m(3) is suggested from the experiments.

Transient pulmonary fibrogenic effect induced by intratracheal instillation of ultrafine amorphous silica in A/J mice.

In order to evaluate the degree of pulmonary fibrosis and to identify the fibrogenic mechanisms induced by ultrafine amorphous silica (UFAS), UFAS suspensions ( approximately 50microl) were instilled intratracheally into A/J mice at doses of 0, 2, 10 and 50mg/kg (n=5 per group). Mice were sacrificed at 24h, 1, 4 and 14 weeks after exposure. Gomori's trichrome staining revealed that UFAS induced severe alveolar epithelial thickening and pulmonary fibrosis at 1 week, though animals almost recovered at 4 and 14 weeks. The mRNA and protein levels of cytokines (IL-4, IL-10, IL-13 and IFN-gamma), matrix metalloproteinases (MMP-2, MMP-9 and MMP-10) and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) in lung tissues were significantly elevated at 24h and 1week post-treatment, though these levels decreased to near the control range at 4 and 14 weeks except IFN-gamma and MMP-2. These results demonstrate that UFAS can induce pulmonary fibrosis in the same way as crystalline silica. However, the degree of fibrosis observed was transient. This study shows that cytokines (IL-4, IL-10, IL-13 and IFN-gamma), MMPs (MMP-2, MMP-9 and MMP-10) and TIMP-1 play important roles in the fibrosis induced by the intratracheal instillation of UFAS.

Twenty-eight-day oral toxicity, genotoxicity, and gender-related tissue distribution of silver nanoparticles in Sprague-Dawley rats.

The antibacterial effect of silver nanoparticles has resulted in their extensive application in health, electronic, and home products. However, while the population exposed to silver nanoparticles continues to increase with ever new applications, silver nanoparticles remain a controversial research area as regards their toxicity to biological systems. In particular, the oral toxicity of silver nanoparticles is of particular concern to ensure public and consumer health. Accordingly, this study tested the oral toxicity of silver nanoparticles (60 nm) over a period of 28 days in Sprague-Dawley rats following Organization for Economic Cooperation and Development (OECD) test guideline 407 with Good Laboratory Practice (GLP) application. Eight-week-old rats, weighing about 283 g for the males and 192 g for the females, were divided into four 4 groups (10 rats in each group): vehicle control, low-dose group (30 mg/kg), middle-dose group (300 mg/kg), and high-dose group (1000 mg/kg). After 28 days of exposure, the blood biochemistry and hematology were investigated, along with a histopathological examination and silver distribution study. The male and female rats did not show any significant changes in body weight relative to the doses of silver nanoparticles during the 28-day experiment. However, some significant dose-dependent changes were found in the alkaline phsophatase and cholesterol values in either the male or female rats, seeming to indicate that exposure to over more than 300 mg of silver nanoparticles may result in slight liver damage. There were no statistically significant differences in the micronucleated polychromatic erythrocytes (MN PCEs) or ratio of polychromatic erythrocytes among the total erythrocytes after silver nanoparticle exposure when compared with the control. Therefore, the present results suggest that silver nanoparticles do not induce genetic toxicity in male and female rat bone marrow in vivo. Nonetheless, the tissue distribution of silver nanopaticles did show a dose-dependent accumulation of silver content in all the tissues examined. In particular, a gender-related difference in the accumulation of silver was noted in the kidneys, with a twofold increase in the female kidneys when compared with the male kidneys.

Comparison of high MRI T1 signals with manganese concentration in brains of cynomolgus monkeys after 8 months of stainless steel welding-fume exposure.

Several pharmacokinetic studies on inhalation exposure to manganese (Mn) have already demonstrated that Mn readily accumulates in the olfactory and brain regions. However, a shortening of the magnetic resonance imaging (MRI) T1 relaxation time or high T1 signal intensity in specific sites of the brain, including the globus pallidus and subcortical frontal white matter, as indicative of tissue manganese accumulation has not yet been clearly established for certain durations of known doses of welding-fume exposure in experimental animals. Accordingly, to investigate the movement of manganese after welding-fume exposure, six cynomolgus monkeys were acclimated and assigned to three dose groups: unexposed, low dose (31 mg/m(3) total suspended particulate [TSP], 0.9 mg/m(3) of Mn), and high dose (62 mg/m(3) TSP, 1.95 mg/m(3) of Mn) of total suspended particulate. The primates were exposed to manual metal arc stainless steel (MMA-SS) welding fumes for 2 h per day in an inhalation chamber system equipped with an automatic fume generator. Magnetic resonance imaging (MRI) studies were conducted before the initiation of exposure and thereafter every month. The tissue Mn concentrations were then measured after a plateau was reached regarding the shortening of the MRI T1 relaxation time. A dose-dependent increase in the Mn concentration was found in the lungs, while noticeable increases in the Mn concentrations were found in certain tissues, such as the liver, kidneys, and testes. Slight increases in the Mn concentrations were found in the caudate, putamen, frontal lobe, and substantia nigra, while a dose-dependent noticeable increase was only found in the globus pallidus. Therefore, the present results indicated that a shortening of the MRI T1 relaxation time corresponded well with the Mn concentration in the globus pallidus after prolonged welding-fume exposure.