title: Bioassay by intratracheal instillation for detection of lung toxicity due to fine particles in F344 male rats.
abstract: We have established and documented an in vivo bioassay for detection of hazards with intratracheally instilled fine particles, which can be used for risk assessment of toxicity of materials inhaled into deep lung tissue of humans (Yokohira et al. Establishment of a bioassay system for detection of lung toxicity due to fine particle instillation: sequential histopathological changes with acute and subacute lung damage due to intratracheal instillation of quartz in F344 male rats. J Toxicol Pathol 2005;18:13-8). For validation we here examined toxicity of fine particles from quartz, hydrotalcite, potassium octatitanate, palladium oxide and carbon black with this bioassay. A total of 108, 10-week-old F344/DuCrj male rats were randomly divided into 8 groups. Groups 1 to 5 underwent intratracheal instillation of the 5 test particles (4 mg/rat) suspended in 0.2 ml vehicle (saline or 10% propylene glycol and 1% sodium carboxymethyl cellulose in saline: PG-CMC) with a specially designed aerolizer, and subgroups of 7 rats were killed on Days 1 and 28 thereafter. Groups 6 and 7 similarly were exposed to saline and PG-CMC, respectively, as vehicle controls, while group 8 was maintained untreated. Using histopathological changes and immunohistochemically assessed bromodeoxyuridine (BrdU) labeling indices, inducible nitric oxide synthase (iNOS) and matrix metalloproteinase-3 (MMP-3) levels as end points, the quartz treated group exhibited high toxicity, while the values for the other particle-treated groups pointed to only slight effects. Although additional efforts are needed to establish advantages and disadvantages with our bioassay, models featuring intratracheal instillation clearly can be useful for detection of acute or subacute lung toxicity due to inhaled fine particles by using histopathological scoring and markers like BrdU and iNOS for screening purposes in short-term studies.
authors.affiliation: Onco-Pathology, Department of Pathology and Host-Defense, Faculty of Medicine, Kagawa University, Kita-gun, Kagawa 761-0793, Japan.
authors.forename: Masanao
authors.initials: M
authors.lastname: Yokohira
authors.forename: Hijiri
authors.initials: H
authors.lastname: Takeuchi
authors.forename: Keiko
authors.initials: K
authors.lastname: Yamakawa
authors.forename: Kousuke
authors.initials: K
authors.lastname: Saoo
authors.forename: Yoko
authors.initials: Y
authors.lastname: Matsuda
authors.forename: Yu
authors.initials: Y
authors.lastname: Zeng
authors.forename: Kyoko
authors.initials: K
authors.lastname: Hosokawa
authors.forename: Katsumi
authors.initials: K
authors.lastname: Imaida
mesh_terms: D000536:Aluminum Hydroxide / Q000008:administration & dosage / Q000633:toxicity; D000818:Animals; D001681:Biological Assay / Q000379:methods*; D015415:Biomarkers / Q000032:analysis; D001973:Bromodeoxyuridine / Q000378:metabolism; D007150:Immunohistochemistry; D008171:Lung Diseases / Q000139:chemically induced / Q000175:diagnosis* / Q000473:pathology; D008276:Magnesium Hydroxide / Q000008:administration & dosage / Q000633:toxicity; D008297:Male; D019278:Matrix Metalloproteinase 3 / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D010165:Palladium / Q000008:administration & dosage / Q000633:toxicity; D052638:Particulate Matter / Q000008:administration & dosage* / Q000009:adverse effects*; D011791:Quartz / Q000008:administration & dosage / Q000633:toxicity; D051381:Rats; D011916:Rats, Inbred F344; D053260:Soot / Q000008:administration & dosage / Q000633:toxicity; D014025:Titanium / Q000008:administration & dosage / Q000633:toxicity
chemical_list: D015415:Biomarkers; D052638:Particulate Matter; D053260:Soot; D011791:Quartz; C010467:hydrotalcite; C021028:potassium octatitanate; D000536:Aluminum Hydroxide; D010165:Palladium; C048320:palladium oxide; D014025:Titanium; D052247:Nitric Oxide Synthase Type II; D019278:Matrix Metalloproteinase 3; D001973:Bromodeoxyuridine; D008276:Magnesium Hydroxide