Fundamental Toxicological Sciences

2022 - Vol. 9 No. 4

2022 - Vol. 9

Original Article
Cryopreserved human hepatocytes culture optimization on polymethylpentene oxygen permeable membranes for drug screening purposes Vol.9, No.4, p.135-144
Mathieu Anoy , Benedikt Scheidecker , Hiroshi Arakawa , Katsuhiro Esashika , Naoki Ishida , Hiroyasu Ito , Hisaaki Yanai , Jun Takahashi , Masaki Nishikawa , Yukio Kato , Yasuyuki Sakai
Released: September 07, 2022
Abstract Full Text PDF[2M]

In vitro culture of primary hepatocytes for drug screening purposes remains a challenge as cells rapidly lose their function in conventional culture conditions. Thin oxygen permeable membranes have shown, through direct oxygenation, beneficial effects for long-term culture and cellular function with freshly isolated hepatocytes. However, culture of cryopreserved hepatocytes, a standard for the industry, has shown limits due to high cellular damage, leading to low cellular function. In addition, high sorption of drug screening compounds on PDMS oxygen permeable membranes has rendered evaluation of different molecules, aimed at the improvement of the culture of those cells difficult. Here, culture of cryopreserved hepatocytes was performed on PMP membranes, known to exhibit exceptionally low sorption characteristics. A mixture of anti-apoptotic and anti-inflammatory compounds to improve cell viability during adhesion was tested and evaluation in terms of cellular damage and drug metabolism was performed after 24 hr and 72 hr. Components of the mixture were shown to have beneficial effect on Reactive Oxygen Species production after 6 hr of adhesion as well as on mitochondrial activity and LDH release after 24 hr. Effects in improving recovery of albumin and drug metabolism, could be efficiently measured after 72 hr as a result of the use of PMP. The presented results demonstrate the compatibility of PMP oxygen-permeable membrane-based culture with cryopreserved hepatocytes for efficient drug screening.

Original Article
Derivation of human health hazard assessment values for toluene under the Japanese Chemical Substances Control Law Vol.9, No.4, p.123-133
Akira Kawashima , Kaoru Inoue , Kazuo Ushida , Kaoru Kai , Hiroshi Suzuki , Mariko Matsumoto , Kenichi Masumura , Akihiko Hirose
Released: September 07, 2022
Abstract Full Text PDF[985K]

Toluene had been designated as a priority assessment chemical substance under the Japanese Chemical Substances Control Law (CSCL), and as a result of prioritization, a detailed human health hazard assessment was conducted under Assessment II. We evaluated its general, reproductive, and developmental toxicities, as well as its genotoxicity and carcinogenicity, based on the hazard information provided by domestic and international risk assessment organizations, and the following hazard assessment values for oral and inhalation exposure are proposed. The hazard assessment value of 0.223 mg/kg/day for oral exposure was calculated from a no-observed-adverse-effect level (NOAEL) of 312 mg/kg/day (equal to an average daily dose of 223 mg/kg/day) based on liver and kidney weight increases in a 13-week oral toxicity study in rats by using an uncertainty factor (UF) of 1,000 (interspecies variation: 10, intraspecies variation: 10, and short test period: 10). The hazard assessment value of 0.1 ppm (0.383 mg/m3) for inhalation exposure was calculated from a NOAEL of 45 ppm (equal to a continuous exposure level of 10.7 ppm) based on toxic effects on the central nervous system found in epidemiological investigations of occupational exposure by using a UF of 100 (intraspecies variation: 10 and severe effect: 10).

Leaf extracts from Camellia sinensis and Argania spinosa suppress oxidative stress and chemokine release in human 3-dimensional cultured epidermis exposed to PM2.5 collected with cyclonic separation Vol.9, No.4, p.117-122
Maori Kono , Tomoaki Okuda , Masayuki Takaishi , Hidefumi Ikeda , Nami Ishihara , Yasuhiro Ishihara
Released: September 07, 2022
Abstract Full Text PDF[959K]

Skin is the primary tissue exposed to ambient air pollution because it acts as an interface between the body and the surrounding atmosphere. We previously reported that particulate matter 2.5 (PM2.5) induced oxidative stress and subsequent chemokine release in the human epidermis, followed by neutrophil chemotaxis. We identified in this study that the leaf extracts from Camellia sinensis and Argania spinosa showed high radical scavenging activity as evaluated by 2,2-diphenyl-1-(2,4,6-trinitrophenyl)-hydrazinyl and 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid assays. PM2.5 exposure induced lipid peroxidation, IL-8 release and neutrophil migration in human 3-dimensional cultured epidermis. Pretreatment with leaf extracts from Camellia sinensis or Argania spinosa significantly suppressed the above harmful effects elicited by PM2.5. Taken together, both extracts can protect the epidermis from PM2.5 exposure. Camellia sinensis and Argania spinosa extracts could be added to a novel cosmetic that protects skin from air pollution.

De novo transgenerational inheritance of male rat hyperactivity by rotenone Vol.9, No.4, p.111-115
Masami Ishido
Released: September 07, 2022
Abstract Full Text PDF[1M]

There is growing evidence of transgenerational effects of a single exposure to chemicals, whose mechanism is implicated to be epigenetic. However, it is largely unknown whether psychiatric diseases such as ADHD or autism caused by environmental chemicals might be transmitted. Rotenone (3 mg/kg), a dopaminergic toxin was orally exposed to Wistar male pups at 5-day old. Their spontaneous motor activity was higher 1.3 fold than that of control rats at 11 weeks of age. At 26 weeks of age, the hyperactive rat (F0) was mated with Wistar female rats. We established the two strains of such mating and found the spontaneous motor activity of the offspring (F1) were much higher 1.5~2.0 fold than those of both control offspring and the parents. Thus, in this study I show the rat hyperactivity caused by neonatal rotenone lesions was transmitted to next generation, indicating the de novo inheritance.