Table 3 BALF cellular and biochemical parameters following single exposures to TiO ₂ NPs at different dose rates

Cell viability (%)

95.6 ± 1.2

95.1 ± 0.7

94.9 ± 0.9

94.7 ± 1.0

92.5 ± 2.3

95.5 ± 1.4

Total cells (Number × 10 ⁷ )

1.39 ± 0.21

1.53 ± 0.07

1.41 ± 0.10

1.62 ± 0.14*

1.32 ± 0.07

1.41 ± 0.16

Alveolar macrophages (%)

99.2 ± 0.3

98.7 ± 1.1

98.6 ± 0.7

97.6 ± 0.9

92.7 ± 1.4

99.0 ± 0.5

(Number × 10 ⁷ )

(1.36 ± 0.2)

(1.52 ± 0.07)

(1.39 ± 0.11)

(1.58 ± 0.12)

(1.22 ± 0.07)

(1.40 ± 0.16)

Neutrophils (%)

0.5 ± 0.1

0.7 ± 0.9

0.8 ± 0.6

1.6 ± 0.6

6.2 ± 1.5

0.6 ± 0.4

(Number × 10 ⁵ )

(1.26 ± 0.69)

(1.01 ± 1.41)

(1.14 ± 0.70)

(2.59 ± 1.08)

(8.18 ± 1.86)*

(0.89 ± 0.56)

Lymphocytes (%) ^a

0.3 ± 0.3

0.6 ± 0.3

0.4 ± 0.3

0.8 ± 0.4

1.1 ± 0.2

0.6 ± 0.4

(Number × 10 ⁴ ) ^b

(3.92 ± 3.31)

(10.12 ± 14.05)

(5.41 ± 4.91)

(13.92 ± 7.67)

(14.89 ± 2.34)

(8.45 ± 4.99)

LDH release (nmol/min/mL)

39.82 ± 3.98

49.31 ± 4.91*

55.01 ± 3.18*

59.91 ± 19.37

38.93 ± 4.99

42.31 ± 2.37

β-Glucuronidase activity (nmol/min/mL) ^c

0.18 ± 0.03

0.08 ± 0.03*

0.11 ± 0.03*

0.37 ± 0.11*

0.20 ± 0.02

.20 ± 0.03

BALF Protein (mg/mL) ^c

0.13 ± 0.01

0.14 ± 0.02

0.13 ± 0.02

0.08 ± 0.02*

0.15 ± 0.01

0.12 ± 0.04

Intratracheal instillation

Saline Controls

TiO ₂

Post exposure time

4 hr

8 hr

24 hr low dose

24 hr high dose

7 days

Cell viability (%)

95.6 ± 1.1

96.0 ± 0.3

94.7 ± 1.3

94.1 ± 0.8

94.5 ± 1.7

93.7 ± 0.7

Total cells (Number × 10 ⁷ )

1.52 ± 0.18

1.39 ± 0.14

1.40 ± 0.32*

1.66 ± 0.08

2.09 ± 0.11*Φ

1.50 ± 0.06

Alveolar macrophages (%)

98.4 ± 0.3

95.0 ± 2.6

89.4 ± 6.9*Φ

95.5 ± 1.4

67.7 ± 3.1*Φ

96.6 ± 1.3

(Number 10 ⁷ )

(1.54 ± 0.12)

(1.32 ± 0.11)

(1.23 ± 0.17)*

(1.59 ± 0.09)

(1.41 ± 0.08)

(1.45 ± 0.04)

Neutrophils (%)

1.0 ± 0.2

3.8 ± 2.8*Φ

9.8 ± 7.1*Φ

3.7 ±1.4*

31.1 ± 2.6*Φ

1.9 ± 1.7

(Number × 10 ⁵ )

(1.47 ± 0.43)

(5.52 ± 4.35)*Φ

(15.46 ± 15.42)*Φ

(6.10 ± 2.31)*Φ

(65.02 ± 6.56)*Φ

(2.84 ± 2.66)

Lymphocytes (%) ^a

0.7 ± 0.3

0.7 ± 0.2

0.8 ± 0.3

0.8 ± 0.1

1.2 ± 0.8

0.9 ± 0.2

(Number × 10 ⁴ ) ^b

(9.55 ± 2.68)

(9.95 ± 3.03)

(10.33 ± 3.76)

(13.74 ± 1.18)

(25.00 ± 18.38)

(13.19 ± 3.34)

LDH release (nmol/min/mL)

46.32 ± 7.36

47.99 ± 3.78

55.19 ± 5.76

68.01 ± 9.12*

76.59 ± 4.15*Φ

58.60 ± 4.22*Φ

β-Glucuronidase activity (nmol/min/mL) ^c

0.22 ± 0.03

0.10 ± 0.03*

0.15 ± 0.02*

0.30 ± 0.06

0.52 ± 0.07*Φ

0.30 ± 0.05*Φ

BALF protein (mg/mL) ^c

0.12 ± 0.02

0.16 ± 0.02

0.18 ± 0.01*Φ

0.07 ± 0.00*

0.14 ± 0.02

0.11 ± 0.01