Low susceptibility of specific inbred colonies of rats to nickel tumorigenesis in soft tissue.
Nickel sarcomatogenesis induced by a single intramuscular injection of 10 mg of nickel subsulfide (NiSS) into the soft tissue of two different colonies of Wistar rats was studied. In spontaneously hypertensive rats (SHR), a specific inbred colony of rats derived from a certain Wistar strain, the sarcoma induction rate was lower than that in common closed colony rats of the same strain (CWR). Sarcomas were induced in only 7 of the 30 rats (23.3%) in the SHR group (15 female and 15 male) but in 21 of the 31 rats (67.7%) in the CWR group (15 female and 16 male) (P < 0.005). The incidence of sarcoma induction was lower in female rats than in male rats in both the SHR (female 13.3% < male 33.3%) and CWR (female 53.3% < male 81.4%) groups. Primary tumors in the SHR group exhibited a lower grade of metastasis to lymph nodes (P < 0.001) and lungs (P < 0.05) than in the CWR group. Our study demonstrated that rats in a certain specific inbred colony are less susceptible to nickel tumorigenesis in soft tissue than rats in a common closed colony.
Ohmori
T
T
Second Department of Pathology, Ehime University School of Medicine, Japan. ohmori@m.ehime-u.ac.jp
Okada
K
K
Terada
M
M
Tabei
R
R
D000818:Animals; D002273:Carcinogens; D005260:Female; D007178:Inbreeding; D008297:Male; D009532:Nickel; D051381:Rats; D011918:Rats, Inbred SHR; D017208:Rats, Wistar; D012513:Sarcoma, Experimental / Q000139:chemically induced*; D012737:Sex Factors; D012983:Soft Tissue Neoplasms / Q000139:chemically induced*
D002273:Carcinogens; D009532:Nickel; C017557:nickel subsulfide