Repeated-dose toxicity and toxicokinetic study of isobutylparaben in rats subcutaneously treated for 13 weeks.

Parabens have historically served as antimicrobial preservatives in a range of consumables such as food, beverages, medications, and personal care products due to their broad-spectrum antibacterial and antifungal properties. Traditionally, these compounds were believed to exhibit low toxicity, causing minimal irritation, and possessing limited sensitization potential. However, recent evidence suggests that parabens might function as endocrine-disrupting chemicals (EDCs). Consequently, extensive research is underway to elucidate potential human health implications arising from exposure to these substances. Among these parabens, particular concerns have been raised regarding the potential adverse effects of iso-butylparaben (IBP). Studies have specifically highlighted its potential for inducing hormonal disruption, significant ocular damage, and allergic skin reactions. This study aimed to evaluate the prolonged systemic toxicity, semen quality, and estrus cycle in relation to endocrine disruption endpoints, alongside assessing the toxicokinetic behavior of IBP in Sprague-Dawley rats following a 13-week repeated subcutaneous administration. The rats were administered either the vehicle (4% Tween 80) or IBP at dosage levels of 2, 10, and 50 mg/kg/day for 13 weeks. Blood collection for toxicokinetic study was conducted on three specified days: day 1 (1st), day 30 (2nd), and day 91 (3rd). Systemic toxicity assessment and potential endocrine effects were based on various parameters including mortality rates, clinical signs, body weights, food and water consumption, ophthalmological findings, urinalysis, hematological and clinical biochemistry tests, organ weights, necropsy and histopathological findings, estrus cycle regularity, semen quality, and toxicokinetic behavior. The findings revealed that IBP induced local irritation at the injection site in males at doses ≥ 10 mg/kg/day and in females at 50 mg/kg/day; however, systemic toxicity was not observed. Consequently, the no-observed-adverse-effect level (NOAEL) for IBP was determined to be 50 mg/kg/day in rats of both sexes, indicating no impact on the endocrine system. The toxicokinetics of IBP exhibited dose-dependent systemic exposure, reaching a maximum dose of 50 mg/kg/day, and repeated administration over 13 weeks showed no signs of accumulation.

Thirteen-week subcutaneous repeated dose toxicity study of butylparaben and its toxicokinetics in rats.

Parabens are widely used preservatives in cosmetics and pharmaceutical products and are approved as food additives. These chemicals have been considered safe for many years. However, the literature classifies parabens as endocrine-disrupting chemicals, and an assessment of their influence on the endocrine system and systemic toxicity is important. This study explored long-term systemic toxicity, effects on the endocrine system, and toxicokinetic behavior after repeated subcutaneous administration of butylparaben to Sprague-Dawley rats. Rats were treated with vehicle (4% Tween 80) or butylparaben at dose levels of 2, 10, and 50 mg/kg/day for 13 weeks. Assessment of systemic toxicity and endocrine-disrupting effects was based on mortality; clinical signs; body weight; food and water consumption; ophthalmological findings; urinalysis; hematology and clinical biochemistry; organ weights; necropsy and histopathological findings; regularity and length of the estrous cycle; semen quality; and toxicokinetic behavior. Female uterine weight and estrous cycle, and male semen quality indicated no estrogenic effects. Butylparaben induced local irritation at the injection site in both sexes at a dose of 50 mg/kg/day, but systemic toxicity was not observed. Therefore, the no-observed-adverse-effect level of butylparaben is set at 50 mg/kg/day in rats of both sexes. Butylparaben was without endocrine system effects at this dose. Butylparaben displays dose-dependent systemic exposure up to the maximum dose of 50 mg/kg/day and repeated administration of butylparaben for 13 weeks shows no bioaccumulation.

A 13-week subchronic toxicity study of a Dioscorea Rhizome water extract in rats.

Dioscorea Rhizome is widely used as a traditional herbal medicine to treat asthma, diarrhea, cough, bronchitis, spermatorrhea, leukorrhea, and rheumatoid arthritis. This study investigated the potential subchronic toxicity of a D. Rhizome water extract (DRWE) after repeated oral administration at 0, 800, 2000, and 5000 mg/kg/day in rats for 13 weeks. During the study period, clinical signs, mortality, body weight, food consumption, water consumption, urinalysis, ophthalmoscopy, hematology, serum biochemistry, gross pathology, organ weights, and histopathology were examined. The 13-week repeated oral administration of DRWE to rats resulted in an increased incidence of zona glomerulosa hypertrophy and hyperplasia in the adrenal gland at dose levels of ≥2000 mg/kg/day in both sexes. However, these findings are considered as non-adverse adaptive changes because of minimal histological changes in the lesions, which were not accompanied by any corresponding alterations in serum electrolytes and adrenal gland weight. No treatment-related adverse effects on clinical signs, body weight, food and water consumption, ophthalmic examination, urinalysis, hematology, serum biochemistry, necropsy findings, and organ weights were observed at any dose tested. Under the present experimental conditions, the no-observed-adverse-effect level of the DRWE was considered to be 5000 mg/kg/day in both sexes, and no target organs were identified.

Evaluation of 13-week subchronic toxicity of Platycodon grandiflorus (Jacq.) A.DC. root extract in rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Platycodi radix is widely used in traditional herbal medicine for bronchitis, asthma, pulmonary tuberculosis, hypertension, hyperlipidemia, and diabetes. However, data on safety of Platycodi radix are insufficient. AIM OF THE STUDY: The present study was performed to evaluate the potential subchronic toxicity of Platycodi radix water extract through a 13-week repeated oral dose experiment in Sprague-Dawley rats. MATERIALS AND METHODS: Forty male and 40 female rats were randomly assigned to four experimental groups: three treatment groups receiving 300, 1000, and 3000 mg/kg/day of Platycodi radix water extract and a vehicle control group receiving sterile distilled water for 13 weeks. RESULTS: Repeated oral administration of the Platycodi radix water extract to rats resulted in an increased incidence of centrilobular hepatocellular hypertrophy in the liver, diffuse follicular cell hypertrophy in the thyroid gland, and squamous hyperplasia of the limiting ridge in the stomach at dose levels of ≥500 mg/kg/day of both genders. However, these findings are considered be adaptive non-adverse changes because these findings were observed without organ weight change or clinical pathology alterations. No treatment-related effects on clinical signs, body weight, food and water consumption, ophthalmic examination, urinalysis, hematology, serum biochemistry, necropsy findings, and organ weights were observed at any dose tested. CONCLUSION: Under the present experimental conditions, the no-observed-adverse-effect level of the Platycodi radix water extract was considered to be ≥ 3000 mg/kg/day in rats, and no target organs were identified.

Evaluation of 13-week repeated oral dose toxicity of Areca catechu in F344/N rats.

This study investigated the potential toxicity of the Areca catechu water extract after 13-week repeated oral administration at 0, 166.7, 500, and 1500 mg/kg/day in rats. During the study period, clinical signs, mortality, body weight, food consumption, water consumption, urinalysis, estrous cycle, sperm count and motility, ophthalmoscopy, hematology, serum biochemistry, gross pathology, organ weights, and histopathology were examined. At 1500 mg/kg/day, both sexes exhibited an increase in the incidence of abnormal clinical signs, which included, decreased body weight gain and food consumption, and increased urine bilirubin, ketone bodies, specific gravity, and protein and kidney weight. An increase in liver weight and estrous cycle alterations was observed in females. Serum biochemical and histopathological investigations revealed an increase in the levels of serum aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase, and the incidence of hepatic necrosis in females. At 500 mg/kg/day, an increase in the incidence of abnormal clinical signs including diarrhea and soiled perineal region, was observed in both sexes. No treatmentrelated effects were observed at 166.7 mg/kg/day. Under the present experimental conditions, the target organs were determined to be the liver, kidney, and female reproductive system in rats. The no-observedeffect level was considered to be 166.7 mg/kg/day in rats.

Safety evaluation of Astragalus extract mixture HT042 and its constituent herbs in Sprague-Dawley rats.

BACKGROUND: Astragalus extract mixture HT042 is a combination of three standardized extracts from Astragalus membranaceus root, Eleutherococcus senticosus stem, and Phlomis umbrosa root, which has proven to stimulate children's height growth. PURPOSE: The aim of this study was to demonstrate the safety of HT042 and its three constituent herbs when administered orally. METHODS: Acute and sub-chronic oral toxicity studies were conducted using male and female Sprague-Dawley rats. In the acute toxicity study, HT042 and each of the herbs was administered at single doses of up to 5000 mg/kg. In the 13-week sub-chronic toxicity study, HT042 was administered at repeated doses of up to 4000 mg/kg/day. RESULTS: In the acute toxicity study of HT042 and each of the herbs, no deaths occurred and there was no indication of toxicity, on the basis of clinical signs, body weight, and necropsy findings. In the sub-chronic toxicity study of HT042, there were no deaths and no changes in clinical signs or the findings of ophthalmic examinations. Although there were some treatment-related changes in other findings, these alterations were not considered toxicologically significant because they remained within normal ranges or recovered during the recovery period. CONCLUSION: The oral approximate lethal doses of HT042 and each of the herbs were > 5000 mg/kg, and the no-observed-adverse-effect level of HT042 was 4000 mg/kg/day in male and female rats.

Spontaneous Peripheral Ameloblastic Odontoma in a Male Sprague-Dawley Rat.

Peripheral ameloblastic odontoma is a rare variant of odontogenic tumor occurring in the extraosseous region. The present report describes a spontaneous tumor in male Sprague-Dawley (SD) rats. The clinically confirmed nodule in the right mandibular region was first observed when the rat was 42 weeks and remained until the terminal sacrifice date when the animal was 48 weeks of age. At necropsy, a well demarcated nodule, approximately 2.5 × 2.0 × 2.0 cm, protruded from the ventral area of the right mandible. The nodule was not attached to mandibular bone and was not continuous with the normal teeth. Histopathologically, the tumor was characterized by the simultaneous occurrence of an ameloblastomatous component and composite odontoma-like elements within the same tumor. The epithelial portion formed islands or cords resembling the follicle or plexiform pattern typical of ameloblastoma and was surrounded by mesenchymal tissue. Formation of eosinophilic and basophilic hard tissue matrix (dentin and enamel) resembling odontoma was observed in the center of the tumor. Mitotic figures were rare, and areas of cystic degeneration were present. Immunohistochemically, the epithelial component was positive for cytokeratin AE1/AE3 (CK AE1/AE3), and the mesenchymal component and odontoblast-like cells were positive for vimentin, in the same manner as in normal teeth. On the basis of these findings, the tumor was diagnosed as a peripheral ameloblastic odontoma in an extraosseous mandibular region in a SD rat. In the present study, we report the uncommon spontaneous peripheral ameloblastic odontoma in the SD rat. We also discuss here the morphological characteristics, origin, histochemical, and immunohistochemical features for the diagnosis of this tumor.

Effect of Coenzyme Q10 on Radiation Nephropathy in Rats.

The kidney is one of the most radiosensitive organs in the abdominal cavity and is the dose-limiting structure in cancer patients receiving abdominal or total body irradiation. In the present study, the effect of coenzyme Q10 (CoQ10) on radiation nephropathy was evaluated in rats. A total of 72 rats were equally randomized into 4 groups: Control, CoQ10, irradiation with 10 Gy (RT) + placebo, or RT + CoQ10. The 2 RT groups received single 10 Gy of abdominal irradiation. The 2 CoQ10 groups were supplemented daily with 1 mL of soybean oil containing 10 mg/kg of CoQ10. The RT + placebo and control groups received same dose of soybean oil. After 24 weeks, laboratory and histopathologic findings were compared. The 2 RT groups showed significant increases in blood urea nitrogen (BUN) and creatinine levels and significant pathologic changes such as glomerulosclerosis and tubulointerstitial fibrosis. CoQ10 supplementation resulted in significant reductions of BUN and creatinine levels compared with the RT + placebo group (P < 0.001 and P = 0.038, respectively). CoQ10 treatment significantly attenuated glomerular and tubular changes of irradiated kidney in semiquantitative analysis (P < 0.001 for both). Administration of CoQ10 can alleviate the radiation-induced nephropathy.

Single and 90-day repeated oral dose toxicity studies of fermented Rhus verniciflua stem bark extract in Sprague-Dawley rats.

Fermented Rhus verniciflua stem bark (FRVSB) extract, an urushiol-free extract of Rhus verniciflua Stokes (RVS) fermented with Fomitella fraxinea, has various biological activities. The present study was carried out to investigate the potential toxicity of the FRVSB extract following single and repeated oral administration to Sprague-Dawley rats. In the single dose toxicity study, the FRVSB extract was administered orally to male and female rats at single doses of 0, 2500, 5000, and 10,000mg/kg. No animals died and no toxic changes were observed in clinical signs, body weight, and necropsy findings during the 15-day period following administration. In the repeated dose toxicity study, the FRVSB extract was administered orally to male and female rats for 90days at doses of 0, 556, 1667, and 5000mg/kg/day. There were no treatment-related adverse effects in clinical signs, body weight, food and water consumption, ophthalmic examination, urinalysis, hematology, serum biochemistry, necropsy findings, organ weight, and histopathology at any dose tested. The approximate lethal dose of the FRVSB extract was >10,000mg/kg in both genders, the oral no-observed-adverse-effect level of the FRVSB extract was >5000mg/kg/day in both genders, and no target organs were identified.

A 6-week oral toxicity study of oral cholera vaccine in sprague-dawley rats.

The present study was carried out to examine the toxicity and target organs of oral cholera vaccine (OCV) after repeated oral administration in Sprague-Dawley rats for 6 weeks (3 administrations, once every 2 weeks). OCV is an inactivated oral cholera vaccine that contains Vibrio cholerae and confers protection against cholera caused by V. cholera serogroups O1 (Inaba and Ogawa serotypes) and O139 (strain 4260B). The animals were orally administered either OCV placebo (negative control) or OCV at a dose equivalent to 240 times the anticipated human dose. Throughout the administration period, no significant change was detected in clinical signs, body weight, food or water consumption, urinalysis results, hematological and clinical biochemistry test results, organ weights, necropsy, or histopathological examination results. Minor changes were found in hematological and clinical biochemistry tests; however, these changes were within normal ranges. The above results suggest that oral administration of OCV in rats did not induce any toxicologically meaningful changes, and the target organs could not be determined. This study was conducted in accordance with the guidelines established by Good Laboratory Practice (2009-183, KFDA, December 22, 2009) and the OECD Principles of Good Laboratory Practice (1997).

Acute and 90-day subchronic toxicity studies of Silk peptide E5K6, in Sprague-Dawley rats.

Acute and 90-day subchronic oral toxicity studies of Silk peptide E5K6 were performed in Sprague-Dawley rats. In the acute toxicity study, Silk peptide E5K6 was administered orally to male and female rats at a single dose of 2000 and 5000 mg/kg. Mortality, clinical signs and body weight changes were monitored for 14 days. There were no treatment-related changes in these parameters. Therefore, the Approximate Lethal Dose (ALD) of Silk peptide E5K6 in male and female rats is higher than 5000 mg/kg. In the subchronic toxicity study, Silk peptide E5K6 was administered orally to male and female rats for 90 days at a single dose of 500, 1000, and 2000 mg/kg. There were no toxicologically significant changes in clinical signs, body weight, food and water consumptions, ophthalmoscopic examination, urinalysis, hematological and serum biochemical examinations, necropsy findings, organ weights and histopathological examination of all of the animals treated with Silk peptide E5K6. These results suggest that the oral No Observed Adverse-Effect Level (NOAEL) of Silk peptide E5K6 is greater than 2000 mg/kg/day in both sexes and the target organs were not established.

Acute and repeated dose toxicity studies of recombinant saxatilin, a disintegrin from the Korean snake (Gloydius saxatilis).

To examine the toxicological effect of saxatilin, a disintegrin isolated from the venom of a Korean snake (Gloydius saxatilis), recombinant saxatilin was highly expressed as a biologically active form in Pichia pastoris, and was successfully purified to homogeneity from the culture broth supernatant. The molecular and biological properties of the recombinant protein were the same as those of its natural form. Plasma half-life of the protein in rat was determined to 13.8 min. The maximum tolerated dose of the recombinant saxatilin was examined in ICR mice. The determined LD(50) values were 400 and 600 mg/kg of the body weight of a male and female mouse, respectively. To investigate the repeated dose toxicity of saxatilin in mice, the test item was intravenously administered to groups of ICR mice every day for 4 weeks. We observed a decrease in locomotor activity, piloerection, and crouching in clinical findings, a decrease of red blood cells (RBCs) in hematology, and hyperplasia of the spleen in histology related to administration of the test item. These results suggest that the target organ of intravenous administration of the test item is the spleen. The no adverse effect level (NOAEL) in this test for both males and females is considered to be 3mg/kg. Our results also indicate that recombinant saxatilin is non-toxic at an administration dose with an anti-platelet effect, and might be a potential anti-adhesion therapeutic agent for thrombosis, cancer, restenosis, cataract, and osteoporosis.