Oral gavage subchronic neurotoxicity and inhalation subchronic immunotoxicity studies of ethylbenzene in the rat.

Oral gavage subchronic neurotoxicity and inhalation subchronic immunotoxicity studies of ethylbenzene in the rat.

Neurotoxicology (2010-02-23)

Abby A Li, Jacques P J Maurissen, John F Barnett, John Foss, Les Freshwater, Robert H Garman, Vanessa L Peachee, Sandra J Hong, Donald G Stump, James S Bus

PMID20171981

ABSTRACT

The potential for neurotoxicological and immunotoxicological effects of ethylbenzene was studied in young adult Crl:CD(SD) rats following 90-day oral (neurotoxicity) or 28-day inhalation (immunotoxicity) exposures. In the neurotoxicity study, ethylbenzene was administered orally via gavage twice daily at 0, 25, 125, or 250 mg/kg per dose (total daily dosages of 0, 50, 250, or 500 mg/kg bwt/day [mg/kg bwt/day]) for 13 weeks and the functional observational battery (FOB), automated tests for motor activity and neuropathological examination were conducted. In the immunotoxicity study, animals were exposed by inhalation to 0, 25, 100, or 500 ppm ethylbenzene (approximately 26, 90, or 342 mg/kg bwt/day as calculated from physiologically based pharmacokinetic modeling). Immunotoxicity was evaluated in female rats using the splenic antibody-forming cell plaque-forming assay in sheep red blood cell sensitized animals. The no-observed-effect level for the oral gavage study was 50mg/kg bwt/day based on increased relative weights of the liver and kidneys in the male rats. The no-observed-adverse-effect level (NOAEL) for adult neurotoxicity was the highest dose tested 500 mg/kg bwt/day. The NOAEL for the immunotoxicity evaluation was the highest tested exposure concentration, 500 ppm (342 mg/kg bwt/day).

MATERIALS

Product Number

Brand

Product Description

736198

Supelco

Ethylbenzene solution, NMR reference standard, 10% in chloroform-d (99.8 atom % D), NMR tube size 5 mm × 8 in. , ultra-thin wall

708046

Sigma-Aldrich

Ethylbenzene solution, NMR reference standard, 10% in chloroform-d (99.8 atom % D)

612065

Sigma-Aldrich

Ethylbenzene solution, NMR reference standard, 0.1% in chloroform-d (99.8 atom % D), TMS 0.01 %, NMR tube size 10 mm × 8 in.

612480

Supelco

Ethylbenzene solution, NMR reference standard, 0.1% in chloroform-d (99.8 atom % D), chromium(III) acetylacetonate 0.1 mg/mL, TMS 0.01 %, NMR tube size 5 mm × 8 in.

551341

Sigma-Aldrich

Ethylbenzene solution, NMR reference standard, 5% in chloroform-d (99.8 atom % D), TMS 2 %, NMR tube size 5 mm × 8 in.

487104

Supelco

Ethylbenzene solution, NMR reference standard, 0.1% in chloroform-d (99.8 atom % D), TMS 0.01 %, NMR tube size 5 mm × 8 in.

487120

Sigma-Aldrich

Ethylbenzene solution, NMR reference standard, 0.1% in chloroform-d (99.8 atom % D), TMS 0.01 %, NMR tube size 8 mm × 8 in.

714917

Sigma-Aldrich

Ethylbenzene solution, NMR reference standard, 0.1% in chloroform-d (99.8 atom % D), TMS 0.01 %, NMR tube size 5 mm × 8 in. , ultra-thin wall

PHR1229

Supelco

Ethylbenzene, Pharmaceutical Secondary Standard; Certified Reference Material

E12508

Sigma-Aldrich

Ethylbenzene, ReagentPlus^®, 99%

296848

Sigma-Aldrich

Ethylbenzene, anhydrous, 99.8%

03079

Supelco

Ethylbenzene, analytical standard