Assessment of the toxicity and carcinogenicity of double-walled carbon nanotubes in the rat lung after intratracheal instillation: a two-year study

Table 3 Incidence of proliferative lesions at the terminal sacrifice^a

	Untreated	Vehicle	DWCNT 0.125 mg/rat	DWCNT 0.250 mg/rat	DWCNT 0.500 mg/rat	MWCNT 0.500 mg/rat
Rats examined	21	25	25	26	24	9^a
Bronchiolo-alveolar hyperplasia (BAH)	4	4	1	4	0	1
Bronchiolo-alveolar adenoma (BAA)	1	1	3	2	3	1
Bronchiolo-alveolar adenocarcinoma (BAC)	0	0	1	2	4	2
BAA + BAC	1	1	4	4	7*	3*
Malignant pleural mesothelioma	0	0	0	1^b	1^b	0
Malignant peritoneal mesothelioma	0	0	1	0	1	0

^aIn the MWCNT-7 group, 16 animals died from malignant mesothelioma after 52 weeks and before 91 weeks. Because of the invasion of the lungs by the mesotheliomas, these animals could not be accessed for development of BAH, BAA, or BAC or the site of mesothelioma development, and therefore, are not included in Table 3
^bThe malignant pleural mesothelioma developed in the visceral pleura
^*Significantly different from the vehicle group: p < 0.05 and 0.001

ISSN: 1743-8977