Assessment of respiratory and systemic toxicity of Benzalkonium chloride following a 14-day inhalation study in rats

Table 6 Histopathological assessment of the lung and nasal cavity tissues in male rats

	Recovery group
Recovery period	2 Weeks				4 Weeks
Concentration (mg/m³)	0	0.8	4	20	0	0.8	4	20
Nasal cavity
Number of animals	5	5	5	5	5	5	5	5
Hyperplasia, transitional epithelium	(0)	(0)	(2)	(5)	(0)	(0)	(0)	(2)
Minimal	0	0	2	0	0	0	0	2
Mild	0	0	0	4	0	0	0	0
Moderate	0	0	0	1	0	0	0	0
Mean ± SD	0	0	0.40 ± 0.55	2.20 ± 0.45	0	0	0	0.40 ± 0.55
Hypertrophy/hyperplasia, mucous cells, respiratory epithelium	(0)	(4)	(5)	(5)	(0)	(0)	(0)	(5)
Minimal	0	4	2	0	0	0	0	4
Mild	0	0	3	2	0	0	0	1
Moderate	0	0	0	3	0	0	0	0
Mean ± SD	0	0.80 ± 0.45	1.60 ± 0.55	2.60 ± 0.55	0	0	0	1.20 ± 0.45
Metaplasia, mucous cells, transitional epithelium	(0)	(4)	(4)	(0)	(0)	(0)	(0)	(0)
Minimal	0	3	1	0	0	0	0	0
Mild	0	1	3	0	0	0	0	0
Mean ± SD	0	1.00 ± 0.71	1.40 ± 0.89	0	0	0	0	0
Infiltration, submucosa, transitional epithelium	(0)	(0)	(0)	(2)	(0)	(0)	(0)	(1)
Minimal	0	0	0	1	0	0	0	1
Mild	0	0	0	1	0	0	0	0
Mean ± SD	0	0	0	0.60 ± 0.89	0	0	0	0.20 ± 0.45
Infiltration, submucosa, respiratory epithelium	(0)	(0)	(0)	(1)	(0)	(0)	(0)	(0)
Mild	0	0	0	1	0	0	0	0
Mean ± SD	0	0	0	0.40 ± 0.89	0	0	0	0
Squamous metaplasia, transitional epithelium	(0)	(0)	(0)	(4)	(0)	(0)	(0)	(1)
Minimal	0	0	0	4	0	0	0	1
Mean ± SD	0	0	0	0.80 ± 0.45	0	0	0	0.20 ± 0.45

0: unremarkable = no presence of histopathologic lesion; 1: minimal = lesions involving< 10% of the tissue of each organ; 2: mild = lesions involving< 10–30% of the tissue of each organ; 3: moderate = lesions involving< 30–50% of the tissue of each organ; 4: marked = lesions involving< 50–70% of the tissue of each organ; 5: severe = lesions involving> 70% of the tissue of each organ

ISSN: 1743-8977