Mechanisms of pulmonary disease in F344 rats after workplace-relevant inhalation exposure to cross-linked water-soluble acrylic acid polymers

Table 5 Comparison of the effects of inhalation exposure to CWAAP-A on histopathological findings in the lungs of male rats in the present study and in our previous 13-week study (Reference: Takeda et al. [8])

Experimental protocol	The present study			Our previous report: Takeda et al. 2022
Exposure concentration (mg/m³)	40	40	40	10	10	10
Recovery period (weeks)	0	2	18	0	4	13
No. of animals examined	6	6	10	8	8	8
Histopathological findings
Male lung
Granulomatous change, alveolar	6	6	10	8	8	8
	< 2 >	< 2 >	< 1 >	< 1.9 >	< 1.9 >	< 1 >
Multifocal lesion, alveolar
Hypertrophy/proliferation of alveolar epithelium	6	6	10	8	8	8
	< 3 >	< 2 >	< 2 >	< 2 >	< 2 >	< 1.8 >
Inflammation, air space	6	6	10	8	8	8
	< 3 >	< 2 >	< 1 >	< 2 >	< 2 >	< 1 >
Cholesterol cleft, air space	0	0	10	0	8	8
			< 1 >		< 1 >	< 1 >
Alveolitis	0	0	10	0	3	8
			< 2 >		< 1 >	< 2 >
Fibrous thickening, interstitial	0	0	10	0	3	8
			< 1 >		< 1 >	< 1 >
Accumulation of lipoproteinous material, air space	6	6	0	8	6	8
	< 2.2 >	< 1.2 >		< 1.9 >	< 1 >	< 1 >

Values indicate number of animals bearing lesions
The values in angle brackets indicate the average severity grade index of the lesion. The average severity grade is calculated using the following equation: Σ(grade × number of animals with grade)/number of affected animals
Grade: 1, slight; 2, moderate; 3, marked; 4, severe
These data are shown in Table 1 in the present study and Tables 2, 3, and 4 in Reference Takeda et al. [8]

ISSN: 1465-993X