Abstract for TR-591

Toxicology and Carcinogenesis Studies of TRIM VX in Wistar Han [Crl:WI (Han)] Rats and B6C3F1/N Mice (Inhalation Studies)

CASRN: TRIM VX
Report Date: November 2016

Abstract

TRIM VX is a metalworking fluid used as a lubricant and coolant liquid and for cleaning tools and parts during cutting, drilling, milling, and grinding. The metalworking fluid class was nominated by the National Institute for Occupational Safety and Health (NIOSH) for study by the National Toxicology Program because of high production volumes, the large number of occupationally exposed workers, the lack of carcinogenicity and chronic toxicology data, and because epidemiologic data indicate an increased incidence of laryngeal cancer in workers exposed to metalworking fluids. TRIM VX was selected as an example soluble oil metalworking fluid following chemical analysis and collaboration with NIOSH. Male and female Wistar Han [Crl:WI (Han)] rats and B6C3F1/N mice were exposed to TRIM VX by inhalation for 3 months or 2 years. Genetic toxicology studies were conducted in Salmonella typhimurium, Escherichia coli, and rat and mouse peripheral blood erythrocytes.

Three-month study in rats

Groups of 10 male and 10 female rats were exposed by whole body inhalation to TRIM VX aerosol at concentrations of 0, 25, 50, 100, 200, or 400 mg/m3 for 6 hours plus T90 (10 minutes) per day, 5 days per week for 14 weeks. All rats survived to the end of the study. The final mean body weight was significantly less in the 25 mg/m3 males. In addition, the final mean body weight and the mean body weight gain of 400 mg/m3 males were significantly less than those of the chamber controls. The absolute and relative lung weights of females exposed to 100 mg/m3 or greater were significantly greater than those of the chamber controls. The absolute and relative liver weights of 200 and 400 mg/m3 females and the relative liver weights of 200 and 400 mg/m3 males were significantly increased; however, no histopathologic changes were noted.

In the lung, there were significantly increased incidences of fibrosis and chronic active inflammation in males and females exposed to 50 mg/m3 or greater and histiocytic cellular infiltration in males and females exposed to 100 mg/m3 or greater. In the nose, there were significantly increased incidences of suppurative inflammation, olfactory epithelium hyaline droplet accumulation, and respiratory epithelium hyaline droplet accumulation in all exposed groups of males and females compared to those in the chamber control groups. There were also significantly increased incidences of goblet cell hyperplasia, and hyperplasia and squamous metaplasia of the respiratory epithelium in 200 and 400 mg/m3 males and females. In the larynx, there were significantly increased incidences of squamous hyperplasia, squamous metaplasia, and chronic active inflammation in all exposed groups of males and females.

Three-month study in mice

Groups of 10 male and 10 female mice were exposed by whole body inhalation to TRIM VX aerosol at concentrations of 0, 25, 50, 100, 200, or 400 mg/m3 for 6 hours plus T90 (10 minutes) per day, 5 days per week for 14 weeks. All mice survived to the end of the study. The mean body weights of 400 mg/m3 males were significantly less than those of the chamber controls. The absolute and relative lung weights of 200 and 400 mg/m3 males and of 100 mg/m3 or greater females were significantly increased. The absolute liver weights of 200 and 400 mg/m3males and females were significantly greater than those of the chamber control groups; the relative liver weights of all exposed male groups and of 200 and 400 mg/m3 females were also significantly increased. The absolute and relative spleen weights of males exposed to 50 mg/m3 or greater and the relative spleen weights of 400 mg/m3 females were significantly increased. There was no evidence of histologic changes in the liver or spleen.

In the lung, the incidences of fibrosis and histiocytic cellular infiltration in males and females exposed to 100 mg/m3 or greater were significantly greater than those in the chamber control groups. There were significantly increased incidences of chronic active inflammation in males exposed to 50 mg/m3 or greater and females exposed to 100 mg/m3 or greater and bronchiole hyperplasia in males and females exposed to 50 mg/m3 or greater. In the nose, there were significantly increased incidences of hyaline droplet accumulation of the olfactory and respiratory epithelium in all exposed groups of males and females and suppurative inflammation in all exposed groups of males and in females exposed to 50 mg/m3 or greater. In the larynx, there were significantly increased incidences of squamous metaplasia in all exposed groups of males and females and squamous hyperplasia in males and females exposed to 100 mg/m3 or greater. There were significantly increased incidences of chronic inflammation in all exposed groups of females.

Two-year study in rats

Groups of 50 male and 50 female rats were exposed by whole body inhalation to TRIM VX aerosol at concentrations of 0, 10, 30, or 100 mg/m3 for 6 hours plus T90 (12 minutes) per day, 5 days per week for 105 weeks. Survival and mean body weights of all exposed groups were similar to those of the chamber control groups.

In the 100 mg/m3 groups, alveolar/bronchiolar carcinomas occurred in two males and alveolar/bronchiolar adenomas occurred in one male and three females. There were significantly increased incidences of alveolar epithelium hyperplasia, alveolar/bronchiolar epithelium hyperplasia, fibrosis, histiocytic cellular infiltration, and chronic active inflammation in all exposed groups of males and females. There were significantly increased incidences of alveolar epithelium squamous metaplasia and lymphohistiocytic hyperplasia of bronchus-associated lymphoid tissue in 100 mg/m3 males and 30 and 100 mg/m3 females and alveolus proteinosis in 30 and 100 mg/m3 males and all exposed groups of females.

In the nose, there were significantly increased incidences of olfactory epithelium glands hyperplasia, goblet cell hyperplasia, suppurative inflammation, and olfactory and respiratory epithelium hyaline droplet accumulation in all exposed groups of males and females. There were also significantly increased incidences of respiratory epithelium hyperplasia in 100 mg/m3 males and all exposed groups of females and transitional epithelium hyperplasia in 100 mg/m3 females.

In the larynx, there were significantly increased incidences of epiglottis squamous hyperplasia, epiglottis squamous metaplasia, and mixed cell infiltration in all exposed male and female groups.

There were significantly increased incidences of lympho-histiocytic hyperplasia in the bronchial and mediastinal lymph nodes in all exposed groups of males and females.

Two-year study in mice

Groups of 50 male and 50 female mice were exposed by whole body inhalation to TRIM VX aerosol at concentrations of 0, 10, 30, or 100 mg/m3 for 6 hours plus T90 (12 minutes) per day, 5 days per week for 105 weeks. Survival and mean body weights of all exposed groups were similar to those of the chamber control groups.

The incidences of alveolar/bronchiolar adenoma or carcinoma (combined) in 100 mg/m3 males and females and of alveolar/bronchiolar carcinoma in 100 mg/m3 females were significantly increased compared to the chamber control incidences. There were significantly increased incidences of alveolar/bronchiolar epithelium hyperplasia, histiocytic cellular infiltration, and chronic inflammation in 30 and 100 mg/m3 males and females, alveolar epithelium hyperplasia in 100 mg/m3 males and females, and fibrosis in 30 and 100 mg/m3 males and 100 mg/m3 females.

In the nose, there were significantly increased incidences of exudate, chronic active inflammation, and olfactory epithelium hyaline droplet accumulation in all exposed male and female groups. In the respiratory epithelium, there were significantly increased incidences of hyaline droplet accumulation in all exposed groups of males and females, atrophy in 30 and 100 mg/m3 males and females, and necrosis in 100 mg/m3 males and 30 and 100 mg/m3 females. The incidences of turbinate atrophy in 30 and 100 mg/m3 males and females, turbinate perforation in 100 mg/m3 males and 30 and 100 mg/m3 females, and nasopharyngeal duct perforation in 30 and 100 mg/m3 males and females were also significantly increased.

In the larynx, there were significantly increased incidences of squamous hyperplasia of the epiglottis in 30 and 100 mg/m3 males and females and squamous metaplasia of the epiglottis in all exposed groups of males and females.

In the bronchial lymph node of 100 mg/m3 males, there were significantly increased incidences of lymphoid hyperplasia and histiocytic cellular infiltration.

Genetic toxicology

TRIM VX gave no evidence of genotoxicity in bacterial mutation tests or in vivo tests for chromosomal damage (micronuclei). No mutagenic activity was observed with TRIM VX in S. typhimurium strains TA98 or TA100 or in E. coli strain WP2 uvrA/pKM101, with or without exogenous metabolic activation (induced rat liver S9). In tests for induction of chromosomal damage in vivo, no increases in the frequencies of micronucleated reticulocytes or erythrocytes were seen in peripheral blood samples from male or female rats or mice exposed to TRIM VX by inhalation for 3 months.

Conclusions

Under the conditions of these 2-year inhalation studies, there was equivocal evidence of carcinogenic activity (see a summary of the Peer Review Panel comments and the public discussion on this Technical Report in Appendix K) of TRIM VX in male Wistar Han rats based on the combined occurrences of alveolar/bronchiolar adenoma or carcinoma of the lung. There was equivocal evidence of carcinogenic activity of TRIM VX in female Wistar Han rats based on the occurrences of alveolar/bronchiolar adenoma of the lung. There was clear evidence of carcinogenic activity of TRIM VX in male B6C3F1/N mice based on the increased combined incidences of alveolar/bronchiolar adenoma or carcinoma of the lung. There was clear evidence of carcinogenic activity of TRIM VX in female B6C3F1/N mice based on the increased combined incidences of alveolar/bronchiolar adenoma or carcinoma (primarily carcinoma) of the lung.

Exposure to TRIM VX resulted in increased incidences of nonneoplastic lesions of the lung, nose, and larynx in male and female rats and mice, the bronchial lymph node in male and female rats and male mice, and the mediastinal lymph node in male and female rats.

National Toxicology Program (NTP). 2016. NTP Technical report on the toxicology and carcinogenesis studies of TRIM VX in Wistar Han [Crl:WI (Han)] rats and B6C3F1/N mice (inhalation studies). Research Triangle Park, NC: National Toxicology Program. Technical Report 591. https://doi.org/10.22427/NTP-TR-591

Studies

Summary of the Two-year Carcinogenesis and Genetic Toxicology Studies of TRIM VX
	Male Wistar Han Rats	Female Wistar Han Rats	Male B6C3F1/N Mice	Female B6C3F1/N Mice
Concentrations in air	0, 10, 30, or 100 mg/m3	0, 10, 30, or 100 mg/m3	0, 10, 30, or 100 mg/m3	0, 10, 30, or 100 mg/m3
Survival rates	36/50, 39/50, 33/50, 34/50	30/50, 33/50, 33/50, 30/50	38/50, 39/50, 37/50, 37/50	35/50, 36/50, 36/50, 30/50
Body weights	Exposed groups similar to the chamber control group	Exposed groups similar to the chamber control group	Exposed groups similar to the chamber control group	Exposed groups similar to the chamber control group
Nonneoplastic effects	Lung: alveolar epithelium, hyperplasia (11/50, 43/50, 45/50, 49/50); alveolar/ bronchiolar epithelium, hyperplasia (4/50, 22/50, 39/50, 46/50); fibrosis (4/50, 43/50, 45/50, 49/50); infiltration cellular, histiocyte (14/50, 50/50, 50/50, 50/50); inflammation, chronic active (7/50, 46/50, 46/50, 48/50); alveolar epithelium, metaplasia, squamous (0/50, 0/50, 0/50, 5/50); bronchus-associated lymphoid tissue, hyperplasia, lymphohistiocytic (0/50, 1/50, 4/50, 6/50); alveolus, proteinosis (0/50, 1/50, 31/50, 45/50) Nose: glands, olfactory epithelium, hyperplasia (0/50, 43/50, 41/50, 49/50); goblet cell, hyperplasia (5/50, 36/50, 37/50, 42/50); inflammation, suppurative (7/50, 46/50, 47/50, 46/50); olfactory epithelium, accumulation, hyaline droplet (20/50, 50/50, 50/50, 50/50); respiratory epithelium, accumulation, hyaline droplet (10/50, 50/50, 48/50, 50/50); respiratory epithelium, hyperplasia (2/50, 7/50, 7/50, 19/50) Larynx: epiglottis, hyperplasia, squamous (0/50, 26/50, 48/50, 50/50); epiglottis, metaplasia, squamous (3/50, 50/50, 50/50, 50/50); infiltration cellular, mixed cell (1/50, 9/50, 27/50, 31/50) Lymph node, bronchial: hyperplasia, lymphohistiocytic (0/39, 17/43, 29/42, 35/42) Lymph node, mediastinal: hyperplasia, lymphohistiocytic (0/43, 20/48, 22/44, 32/43	Lung: alveolar epithelium, hyperplasia (8/50, 43/50, 49/50, 50/50); alveolar/ bronchiolar epithelium, hyperplasia (2/50, 9/50, 31/50, 50/50); fibrosis (5/50, 35/50, 49/50, 50/50); infiltration cellular, histiocyte (16/50, 48/50, 50/50, 50/50); inflammation, chronic active (5/50, 46/50, 50/50, 50/50); alveolar epithelium, metaplasia, squamous (0/50, 3/50, 9/50, 21/50); bronchus-associated lymphoid tissue, hyperplasia, lymphohistiocytic (0/50, 2/50, 7/50, 10/50); alveolus, proteinosis (1/50, 15/50, 41/50, 48/50) Nose: glands, olfactory epithelium, hyperplasia (0/50, 32/50, 43/49, 46/50); goblet cell, hyperplasia (3/50, 36/50, 40/49, 47/50); inflammation, suppurative (1/50, 46/50, 47/49, 48/50); olfactory epithelium, accumulation, hyaline droplet (14/50, 50/50, 49/49, 50/50); respiratory epithelium, accumulation, hyaline droplet (5/50, 50/50, 48/49, 50/50); respiratory epithelium, hyperplasia (0/50, 7/50, 8/49, 25/50); transitional epithelium, hyperplasia (5/50, 11/50, 4/49, 21/50) Larynx: epiglottis, hyperplasia, squamous (1/50, 24/50, 41/50, 50/50); epiglottis, metaplasia, squamous (0/50, 49/50, 50/50, 50/50); infiltration cellular, mixed cell (0/50, 9/50, 18/50, 22/50) Lymph node, bronchial: hyperplasia, lymphohistiocytic (1/37, 18/37, 37/44, 31/36) Lymph node, mediastinal: hyperplasia, lymphohistiocytic (0/46, 11/49, 14/46, 28/45)	Lung: alveolar/bronchiolar epithelium, hyperplasia (3/50, 7/50, 15/49, 50/50); infiltration cellular, histiocyte (5/50, 9/50, 15/49, 49/50); inflammation, chronic (5/50, 12/50, 16/49, 50/50); alveolar epithelium, hyperplasia (3/50, 3/50, 7/49, 47/50); fibrosis (0/50, 2/50, 5/49, 45/50) Nose: exudate (2/49, 11/50, 35/49, 49/50); inflammation, chronic active (3/49, 33/50, 39/49, 50/50); olfactory epithelium, accumulation, hyaline droplet (2/49, 46/50, 48/49, 50/50); respiratory epithelium, accumulation, hyaline droplet (7/49, 49/50, 49/49, 50/50); respiratory epithelium, atrophy (0/49, 1/50, 20/49, 40/50); respiratory epithelium, necrosis (2/49, 1/50, 2/49, 23/50); turbinate, atrophy (0/49, 2/50, 5/49, 14/50); turbinate, perforation (0/49, 0/50, 1/49, 13/50); nasopharyngeal duct, perforation (0/49, 1/50, 11/49, 19/50) Larynx: epiglottis, hyperplasia, squamous (1/48, 2/49, 14/49, 30/49); epiglottis, metaplasia, squamous (0/48, 49/49, 49/49, 49/49) Lymph node, bronchial: hyperplasia, lymphoid (3/38, 3/37, 2/39, 14/39); infiltration cellular, histiocyte (0/38, 1/37, 0/39, 7/39)	Lung: alveolar/bronchiolar epithelium, hyperplasia (0/50, 3/50, 8/50, 45/50); infiltration cellular, histiocyte (1/50, 4/50, 15/50, 48/50); inflammation, chronic (1/50, 6/50, 26/50, 47/50); alveolar epithelium, hyperplasia (0/50, 0/50, 2/50, 43/50); fibrosis (0/50, 0/50, 2/50, 42/50) Nose: exudate (8/50, 17/50, 48/50, 49/50); inflammation, chronic active (4/50, 25/50, 49/50, 49/50); olfactory epithelium, accumulation, hyaline droplet (14/50, 48/50, 50/50, 50/50); respiratory epithelium, accumulation, hyaline droplet (23/50, 50/50, 50/50, 50/50); respiratory epithelium, atrophy (1/50, 2/50, 28/50, 39/50); respiratory epithelium, necrosis (0/50, 2/50, 13/50, 23/50); turbinate, atrophy (0/50, 0/50, 10/50, 19/50); turbinate, perforation (0/50, 0/50, 6/50, 6/50); nasopharyngeal duct, perforation (0/50, 0/50, 14/50, 17/50) Larynx: epiglottis, hyperplasia, squamous (4/50, 3/50, 16/50, 42/50); epiglottis, metaplasia, squamous (0/50, 50/50, 50/50, 50/50)
Neoplastic effects	None	None	Lung: alveolar/bronchiolar adenoma or carcinoma (14/50, 14/50, 11/49, 23/50)	Lung: alveolar/bronchiolar carcinoma (5/50, 3/50, 6/50, 14/50); alveolar/bronchiolar adenoma or carcinoma (9/50, 8/50, 8/50, 20/50)
Equivocal findings	Lung: alveolar/bronchiolar carcinoma (0/50, 0/50, 0/50, 2/50); alveolar/bronchiolar adenoma or carcinoma (0/50, 0/50, 0/50, 3/50)	Lung: alveolar/bronchiolar adenoma (0/50, 0/50, 1/50, 3/50)	None	None
Level of evidence of carcinogenic activity	Equivocal evidence	Equivocal evidence	Clear evidence	Clear evidence
Genetic toxicology
Bacterial gene mutations:		Negative in S. typhimurium strains TA98 and TA100 and in E. coli strain WP2 uvrA/pKM101 with and without S9
Micronucleated erythrocytes Rat peripheral blood in vivo: Mouse peripheral blood in vivo:		Negative in males and females Negative in males and females