Kyoung-Sik Moon

Subchronic Oral Dose Toxicity of Freeze-dried Powder of Allomyrina dichotoma Larvae

The objective of this study was to investigate the toxicological information of freeze-dried powder from Allomyrina dichotoma (A. dichotoma) larvae as a food ingredient. The powder, suspended in distilled water, was administered once daily by oral gavage to four groups of Sprague-Dawley (SD) rats at dose levels of 0 (vehicle control), 250, 850, and 2500 mg/kg/day. After 13 wks of repeated administration, the standard toxicological parameters such as mortality, clinical signs, body weight, food consumption, ophthalmologic examination, clinical pathology, organ weights and macro/microscopic examination were applied for assessment of general toxicity. In addition, serum IgE and histamine levels were determined to evaluate allergenicity. The freeze-dried powder from A. dichotoma larvae did not produce treatmentrelated changes or findings in any toxicological parameters in either sex of any dosed groups except for slight increases in serum histamine levels at 2500 mg/kg/day. The changes were considered not to be adverse since the magnitude was minimal. In conclusion, the NOAEL (No Observed Adverse Effect Level) of the freeze-dried powder from A. dichotoma larvae was determined to be 2500 mg/kg/day or more in both sexes of SD rats and it is considered a candidate to be edible material.

Increased serum bile acid concentration following low-dose chronic administration of thioacetamide in rats, as evidenced by metabolomic analysis

A liquid chromatography/time-of-flight mass spectrometry (LC/TOF-MS)-based metabolomics approach was employed to identify endogenous metabolites as potential biomarkers for thioacetamide (TAA)-induced liver injury. TAA (10 and 30mg/kg), a well-known hepatotoxic agent, was administered daily to male Sprague-Dawley (SD) rats for 28days. We then conducted untargeted analyses of endogenous serum and liver metabolites. Partial least squares discriminant analysis (PLS-DA) was performed on serum and liver samples to evaluate metabolites associated with TAA-induced perturbation. TAA administration resulted in altered levels of bile acids, acyl carnitines, and phospholipids in serum and in the liver. We subsequently demonstrated and confirmed the occurrence of compromised bile acid homeostasis. TAA treatment significantly increased serum levels of conjugated bile acids in a dose-dependent manner, which correlated well with toxicity. However, hepatic levels of these metabolites were not substantially changed. Gene expression profiling showed that the hepatic mRNA levels of Ntcp, Bsep, and Oatp1b2 were significantly suppressed, whereas those of basolateral Mrp3 and Mrp4 were increased. Decreased levels of Ntcp, Oatp1b2, and Ostα proteins in the liver were confirmed by western blot analysis. These results suggest that serum bile acids might be increased due to the inhibition of bile acid enterohepatic circulation rather than increased endogenous bile acid synthesis. Moreover, serum bile acids are a good indicator of TAA-induced hepatotoxicity.

Comparative gene expression analysis in the liver, kidney and blood vessels during renal injury after repeated exposure to tacrolimus in Sprague-Dawley rats

To elucidate the molecular mechanisms associated with renal injury based on multi-organ interactions, we simultaneously examined the changes in expression profiles of the liver, kidneys, and blood vessels after treatment with the nephrotoxic drug tacrolimus. Sprague-Dawley rats were treated daily with tacrolimus and sacrificed 28 d after oral administration. Serum biochemistry analysis of the major injury markers was performed. Histopathological characteristics were also observed. Total RNA was extracted from the liver, kidneys, and blood vessels from the thoracic aorta, followed by microarray analysis. Differentially expressed genes were selected based on 1.5-fold changes and statistical significance (P<0.05). The effects of three dosages of tacrolimus on transcription levels were analyzed within and among the three organs. Gene functions, as well as the biological and toxicological functions of the differentially regulated genes, were analyzed using Ingenuity Pathways Analysis (IPA). IPA identified genes involved in metabolic activation, including lipid metabolism, renal tubule injury, and cell proliferation in tacrolimus-treated livers, kidneys, and blood vessels, respectively. In response to tacrolimus treatment, genes related to lipid metabolic responses were regulated in the three organs similarly. Genes associated with inflammatory response were regulated in the liver and kidneys similarly. Based on the results from this study, we suggest the molecular pathways involved in the response to tacrolimus in multiple organs. We also provide information about candidate genes, to evaluate the toxicity induced by tacrolimus. These results might be helpful to elucidate the underlying mechanisms of nephrotoxicity by interaction among multiple organs.

Tumorigenicity Evaluation of Umbilical Cord Blood-derived Mesenchymal Stem Cells.

Mesenchymal stem cells (MSCs) have been identified in multiple types of tissue and exhibit characteristic self-renewal and multi-lineage differentiation abilities. However, the possibility of oncogenic transformation after transplantation is concerning. In this study, we investigated the tumorigenic potential of umbilical cord blood-derived MSCs (hUCB-MSCs) relative to MRC-5 and HeLa cells (negative and positive controls, respectively) both in vitro and in vivo. To evaluate tumorigenicity in vitro, anchorage-independent growth was assessed using the soft agar colony formation assay. hUCB-MSCs and MRC-5 cells formed few colonies, while HeLa cells formed a greater number of larger colonies, indicating that hUCB-MSCs and MRC-5 cells do not have anchorage-independent proliferation potential. To detect tumorigenicity in vivo, hUCB-MSCs were implanted as a single subcutaneous injection into BALB/c-nu mice. No tumor formation was observed in mice transplanted with hUCB-MSCs or MRC-5 cells based on macroand microscopic examinations; however, all mice transplanted with HeLa cells developed tumors that stained positive for a human gene according to immunohistochemical analysis. In conclusion, hUCB-MSCs do not exhibit tumorigenic potential based on in vitro and in vivo assays under our experimental conditions, providing further evidence of their safety for clinical applications.

Characterization of urinary metabolites as biomarkers of colistin-induced nephrotoxicity in rats by a liquid chromatography/mass spectrometry-based metabolomics approach.

Colistin is a polypeptide antibiotic that effectively treats infections caused by multidrug-resistant Gram-negative bacteria, but its clinical use is limited due to nephrotoxicity. The purpose of the present study was to identify biomarkers of colistin-induced nephrotoxicity and to further characterize the mechanisms underlying this process by analyzing urinary metabolites using untargeted metabolomic approach. Rats receiving intraperitoneal administration of colistin sodium methanesulfonate (CMS) (25 or 50mg/kg) exhibited histopathological changes in the kidney and increased blood urea nitrogen levels. Additionally, the levels of phenylalanine, tryptophan, and tyrosine in the urine of the CMS-treated group were significantly higher than those of the control group, suggesting that colistin caused proximal tubular damage. Urinary acetylcarnitine and butyrylcarnitine levels also increased after CMS treatment, but the levels of purine metabolites and metabolites related to the tricarboxylic acid cycle were reduced. The most significant increase in the CMS-treated groups was observed in creatine levels. CMS-induced selective nephrotoxicity may be attributed to relatively high tissue concentrations of colistin in the kidney. Taken together, our results indicate that high levels of colistin in the kidney caused perturbations in the tricarboxylic acid cycle, amino acid metabolism, creatine metabolism, and purine metabolism and ultimately led to kidney injury.

Toxicological safety evaluation of freeze-dried Protaetia brevitarsis larva powder

Highlights • General toxicity and genotoxicity of freeze-dried P. brevitarsis larva powder was investigated.• In rats, LD50 and NOAEL set at >5000 and 3000 mg/kg, respectively.• No aberrant changes in Ig E and histamine concentration were observed in the 13-week oral repeated dose study.• No evidence of mutagenic and carcinogenic potential was observed in the genotoxicity studies.

Subchronic oral toxicity study of Korean red ginseng extract in Sprague-Dawley rats with a 4-week recovery period

ABSTRACT Ginseng is a major herbal remedy used in Asian countries for thousands of years and known to restore and enhance vital energy. Korean red ginseng, which is processed by steaming and drying fresh Panax ginseng, is most popular and contains unique ginsenosides, which have anticancer and anti‐inflammatory properties. The present study was carried out to evaluate the repeated oral dose toxicity of Korean red ginseng extract. The test article was administered orally once a day to male and female Sprague‐Dawley rats at dose levels of 0, 500, 1000, or 2000 mg/kg/day for 13 consecutive weeks (15 animals/sex/group in the vehicle control and 2000 mg/kg/day groups, and 10 animals/sex/group in the 500 and 1000 mg/kg/day groups). Ten animals per group were sacrificed at the end of the 13‐week treatment period, and the remaining rats were sacrificed after a 4‐week recovery period. Administration of Korean red ginseng extract did not result in any toxicologically significant changes in mortality, body weight, food consumption, ophthalmoscopy, hematology, serum biochemistry, gross pathological findings, absolute/relative organ weights, or histopathology. It was established that the no observed adverse effect level (NOAEL) of the test article was 2000 mg/kg/day for both sexes in this study. HighlightsThe 13‐week repeated oral dose toxicity of Korean red ginseng extract was evaluated in SD rats.Administration of Korean red ginseng extract did not result in any toxicologically significant changes.The no observed adverse effect level (NOAEL) was 2000 mg/kg/day for both.

Erratum to “Evaluation of Genotoxicity and 28-day Oral Dose Toxicity on Freeze-dried Powder of Tenebrio molitor Larvae (Yellow Mealworm)” [Toxicol. Res. 30 (2014) 121-130]

[This corrects the article on p. 121 in vol. 30, PMID: 25071922.].

Pathological features of bone marrow transplantation-related toxicity in a mouse

In this case report, we present a mock-transduced bone marrow (BM) transplantation in a mouse, which was found moribund and autopsied to evaluate pathogenesis. Macroscopically, red discoloration of systemic organs was observed. Hematological values revealed a decrease in white blood cells, red blood cells, hematocrit, hemoglobin, and platelets, but an increase in reticulocytes. In BM cytology, hematopoietic cell lines were severely depleted. Histopathologically, hemorrhage in the cerebellar parenchyma, hemosiderin deposition and hemorrhage in the heart, necrosis and telangiectasia in liver, pulmonary parenchymal cysts, spermatogenic germ cells necrosis, atrophy and hemorrhage in testis, oligospermia and hemorrhage in the epididymis, and atrophy of BM, thymus and spleen were observed. In conclusion, autoimmune-like complications such as hematological value change, BM dysplasia and systemic hemorrhage appear to be the lethal cause of the mouse transplanted with mock-transduced BM.