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Table 9 Microscopic findings in the tracheobronchial lymph nodes of male and female rats 24 h and 90 days after a 90-day exposure to Graphistrength© C100

From: Lung inflammation and lack of genotoxicity in the comet and micronucleus assays of industrial multiwalled carbon nanotubes Graphistrength© C100 after a 90-day nose-only inhalation exposure of rats

 

Males

Females

Target concentration (mg/m3)

0

0.05

0.25

5.0

0

0.05

0.25

5.0

Number examined

10/10

10/8

10/9

10/10

10/8

9/10

10/10

10/10

(24 h/90 days)

Black particle deposition

        

minimal

-

-

8/5

-

-

-

5/3

1

slight

-

-

-/2

6/3

-

-

-

7/1

moderate

-

-

-

4/7

-

-

-

1/9

Mean severitya

-

-

0.8/0.9

2.4/2.7

-

-

0.5/0.3

1.8/2.9

Increased lymphocytes, cortex/paracortex

        

minimal

-

-

3/-

4/7

-

-

1/-

3/6

slight

-

-

-

3/2

-

-

-

7/-

moderate

-

-

-

3/-

-

-

-

-

Mean severitya

-

-

0.3/-

1.9/1.1

-

-

0.1/-

1.7/0.6

Endothelial vacuolation, high endothelial venule

        

minimal

-

-

1/-

1/2

-

-

-

2/5

slight

-

-

1/-

7/1

-

-

-

5/-

Mean severitya

-

-

0.3/-

1.5/0.4

-

-

-

1.2/0.5

  1. Histopathological findings were graded in severity using a five point system of minimal (grade 1), slight (grade 2), moderate (grade 3), marked (grade 4) or severe (grade 5)a: mean severity is ∑ number of animals x severity / number of examined organs in the group
  2. a: mean severity is ∑ number of animals x severity / number of examined organs in the group - : no animal affected