Assessment of acute inhalation toxicity of citric acid and sodium hypochlorite in rats

Background@#Citric acid (CA) and sodium hypochlorite (NaOCl) have been used to disinfect animals to protect them against avian influenza and foot-and-mouth disease. @*Objectives@#We performed a good laboratory practice (GLP)-compliant animal toxicity study to assess the acute toxic effects of CA and NaOCl aerosol exposure in Sprague-Dawley rats. @*Methods@#Groups of five rats per sex were exposed for 4 h to four concentrations of the two chemicals, i.e., 0.00, 0.22, 0.67, and 2.00 mg/L, using a nose-only exposure. After a single exposure to the chemicals, clinical signs, body weight, and mortality was observed during the observation period. On day 15, an autopsy, and then gross findings, and histopathological analysis were performed. @*Results@#After exposure to CA and NaOCl, body weight loss was observed but recovered.Two males died in the CA 2.00 mg/L group and, two males and one female died in the 2.00 mg/L NaOCl group. In the gross findings and histopathological analysis, discoloration of the lungs was observed in the CA exposed group and inflammatory lesions with discoloration of the lungs were observed in the NaOCl exposed group. These results suggest that the lethal concentration 50 (LC50) of CA is 1.73390 mg/L for males and > 1.70 mg/L for females. For NaOCl, the LC50 was 2.22222 mg/L for males and 2.39456 mg/L for females. @*Conclusions@#The Globally Harmonized System is category 4 for both CA and NaOCl. In this study, the LC50 results were obtained through a GLP-based acute inhalation toxicity assessment. These results provide useful data to reset safety standards for CA and NaOCl use.

International regulatory considerations pertaining to the development of stem cell-based veterinary medicinal products

Stem cell-based products (SCPs) are an emerging field of veterinary medicine that focuses on the regeneration, repair, or replacement of damaged tissues or organs. However, there are some issues in applying the traditional regulatory guideline for the approval of SCPs as veterinary medicinal products. This article describes the positions of Korea, US, and EU regarding SCPs, and compares the regulatory guidelines of each country for their safety evaluation. Although there are some differences in the regulatory guidelines, similar considerations in identifying the quality of SCPs and their safety has adopted. Overall, these guidelines need to be harmonized among countries.

Identification of urinary microRNA biomarkers for in vivo gentamicininduced nephrotoxicity models

Background@#Although previous in vivo studies explored urinary microRNA (miRNA), there is no agreement on nephrotoxicity-specific miRNA biomarkers. @*Objectives@#In this study, we assessed whether urinary miRNAs could be employed as biomarkers for nephrotoxicity. @*Methods@#For this, literature-based candidate miRNAs were identified by reviewing the previous studies. Female Sprague-Dawley rats received subcutaneous injections of a single dose or repeated doses (3 consecutive days) of gentamicin (GEN; 137 or 412 mg/kg). The expression of miRNAs was analyzed by real-time reverse transcription-polymerase chain reaction in 16 h pooled urine from GEN-treated rats. @*Results@#GEN-induced acute kidney injury was confirmed by the presence of tubular necrosis.We identified let-7g-5p, miR-21-3p, 26b-3p, 192-5p, and 378a-3p significantly upregulated in the urine of GEN-treated rats with the appearance of the necrosis in proximal tubules.Specifically, miR-26-3p, 192-5p, and 378a-3p with highly expressed levels in urine of rats with GEN-induced acute tubular injury were considered to have sensitivities comparable to clinical biomarkers, such as blood urea nitrogen, serum creatinine, and urinary kidney injury molecule protein. @*Conclusions@#These results indicated the potential involvement of urinary miRNAs in chemical-induced nephrotoxicity, suggesting that certain miRNAs could serve as biomarkers for acute nephrotoxicity.

Acetylcholinesterase activity in the brain of wild birds in Korea—2014 to 2016

Acetylcholinesterase (AChE) activity level can be used as a diagnostic marker for anticholinesterase pesticide poisoning. In this study, we aimed to establish a baseline level of normal brain AChE activity in wild birds. AChE activity was measured in the brains of 87dead wild birds (26 species). The level of AChE activity ranged from 6.40 to 15.9 µmol/min/g of brain tissue in normal wild birds. However, the brain tissue AChE activity level in wild birds exposed to organophosphate (OP) pesticide was 48.0%–96.3% of that in the normal birds. These results may serve as reference values to facilitate routine diagnosis and monitoring of OP-poisoned wild birds.

Guideline on safety evaluation of cell-based medicinal products for animal use

With the increased use of cell therapy in the veterinary sector, there is a growing demand for the development of cell-based medicinal products and the determination of their safety. Currently, the Korean Animal and Plant Quarantine Agency has established a guideline for evaluating the safety of cell-based medicinal products for animal use. The guideline includes items related to definition, classification, management, manufacturing procedure and quality control (standard and test method), stability testing, toxicity testing, pharmacological testing, and performance of clinical trials. In addition, testing protocols related to safety assessment of animal cell-based products such as chromosome karyotyping, tumorigenicity testing, confirmatory testing of biodistribution and kinetics, and target animal safety testing are described in detail. Moreover, because cell-based medicinal products are novel therapies, deviations from traditional designs may be justified in order to obtain relevant safety information on the treatment. Additionally, this guideline can be amended on the basis of new scientific findings.

High-content analysis of in vitro hepatocyte injury induced by various hepatotoxicants

In vitro prediction of hepatotoxicity can enhance the performance of non-clinical animal testing for identifying chemical hazards. In this study, we assessed high-content analysis (HCA) using multi-parameter cell-based assays as an in vitro hepatotoxicity testing model using various hepatotoxicants and human hepatocytes such as HepG2 cells and human primary hepatocytes (hPHs). Both hepatocyte types were exposed separately to multiple doses of ten hepatotoxicants associated with liver injury whose mechanisms of action have been described. HCA data were obtained using fluorescence probes for nuclear size (Hoechst), mitochondrial membrane potential (TMRM), cytosolic free calcium (Fluo-4AM), and lipid peroxidation (BODIPY). Cellular alterations were observed in response to all hepatotoxicants tested. The most sensitive parameter was TMRM, with high sensitivity at a low dose, next was BODIPY, followed by Fluo-4AM. HCA data from HepG2 cells and hPHs were generally concordant, although some inconsistencies were noted. Both hepatocyte types showed mild or severe mitochondrial impairment and lipid peroxidation in response to several hepatotoxicants. The results demonstrate that the application of HCA to in vitro hepatotoxicity testing enables more efficient hazard identification, and further, they suggest that certain parameters could serve as sensitive endpoints for predicting the hepatotoxic potential of chemical compounds.

Plasma haptoglobin and immunoglobulins as diagnostic indicators of deoxynivalenol intoxication

This study aimed to discover potential biomarkers for dioxynivalenol (DON) intoxication. B6C3F1 male mice were rally exposed to 0.83, 2.5 and 7.5 mg/kg body weight (bw) DON for 8 days and the differential protein expressions in their blood plasma were determined by SELDI - Time-of-Flight/Mass Spectrometry (TOF/MS) and the immunoglobulins (Igs) G, A, M and E in the serum were investigated. 11.7 kDa protein was significantly highly expressed according to DON administration and this protein was purified by employing a methyl ceramic HyperD F column with using optimization buffer for adsorption and desorption. The purified protein was identified as a haptoglobin precursor by peptide mapping with using LC/Q-TOF/MS and MALDI-TOF/MS and this was confirmed by western blotting and ELISA. IgG and IgM in serum were decreased in a dose-dependent manner and IgA was decreased at 7.5 mg/kg bw DON administration, but the IgE level was not changed. To compare the expressions of haptoglobin and the Igs patterns between aflatoxin B1 (AFB1), zearalenone (ZEA) and DON intoxications, rats were orally administered with AFB1 1.0, ZEA 240 and DON 7.5 mg/kg bw for 8 days. Haptoglobin was increased only at DON 7.5 mg/kg bw, while it was slightly decreased at ZEA 240 mg/kg bw and it was not detected at all at AFB1 1.0 mg/kg bw. IgG and IgA were decreased by DON, but IgG, IgA, IgM and IgE were all increased by AFB1. No changes were observed by ZEA administration. These results show that plasma haptoglobin could be a diagnostic biomarker for DON intoxication when this is combined with examining the serum Igs.