Tiotropium bromide exerts anti-inflammatory effects during resistive breathing, an experimental model of severe airway obstruction

Figures & data

Table 1 Effect of tiotropium on respiratory system mechanics after 6 h of 40% IRB

	ctr	ctr+tiotropium	40% IRB	40% IRB+tiotropium
Rn (cm H2O·s/mL)	0.05±0.00	0.05±0.00	0.04±0.00	0.04±0.00
G (cm H2O/mL)	0.49±0.01	0.49±0.01	0.51±0.02	0.55±0.03
H (cm H2O/mL)	2.50±0.09	2.34±0.05	2.84±0.07*	2.81±0.23*
Cst (mL/cm H2O)	0.58±0.01	0.58±0.01	0.47±0.01*	0.51±0.02*
Hysteresis (cm H2O·mL)	3.56±0.32	3.54±0.15	4.06±0.57	4.82±1.13

Notes: R_n, Newtonian resistance of the airways; G, tissue viscance (viscous dissipation of energy) and H, tissue elasticity. Data presented as mean ± SEM.

* P<0.05 to ctr. n=6–9 per group.

Abbreviations: Cst, static compliance; IRB, inspiratory resistive breathing; ctr, control; SEM, standard error of the mean.

Figure 1 The effect of tiotropium bromide on lung inflammation following 40% of IRB.

Notes: Tiotropium inhalation prior to 40% of IRB significantly attenuated the increase in the total cell count in BALf (A), by reducing both macrophage and neutrophil numbers (C). Tissue protein levels of IL-1β and IL-6 returned to ctr values following tiotropium inhalation (B and D, respectively). Data presented as mean ± SEM. White bar, ctr; gray bar, ctr plus tiotropium; black bar, 40% of IRB and dark gray bar, 40% of IRB plus tiotropium. *P<0.05 to ctr and ^#P<0.05 to 40% of IRB. n=5–8 per group.

Abbreviations: IRB, inspiratory resistive breathing; BALf, bronchoalveolar lavage fluid; ctr, control; SEM, standard error of the mean.

Figure 2 The effect of tiotropium bromide on lung permeability and injury following 40% of IRB.

Notes: Tiotropium bromide attenuated the increase in total protein levels in BALf (A). Instead, respiratory system elasticity was not affected by tiotropium (B). Finally, following tiotropium inhalation, no increase in total lung injury score was noticed after 40% of IRB (C). Data presented as mean ± SEM. White bar, ctr; gray bar, ctr plus tiotropium; black bar, 40% of IRB and dark gray bar, 40% of IRB plus tiotropium. *P<0.05 to ctr and ^#P<0.05 to 40% of IRB. n=5–8 per group.
Abbreviations: IRB, inspiratory resistive breathing; BALf, bronchoalveolar lavage fluid; SEM, standard error of the mean; ctr, control; au, arbitrary unit.

Table 2 Effect of tiotropium on respiratory system mechanics after 6 h of 50% IRB

	ctr	ctr+tiotropium	50% IRB	50% IRB+tiotropium
Rn (cm H2O·s/mL)	0.05±0.00	0.05±0.00	0.05±0.00	0.05±0.00
G (cm H2O/mL)	0.50±0.01	0.50±0.02	0.60±0.04*	0.61±0.02*
H (cm H2O/mL)	2.58±0.11	2.46±0.06	3.17±0.09*	3.14±0.04*
Cst (mL/cm H2O)	0.55±0.02	0.56±0.01	0.45±0.01*	0.43±0.01*
Hysteresis (cm H2O·mL)	3.99±0.21	3.72±0.17	5.20±0.86*	3.42±0.12#

Notes: R_n, Newtonian resistance of the airways; G, tissue viscance (viscous dissipation of energy) and H, tissue elasticity. Data presented as mean ± SEM.

* P<0.05 to ctr and

# P<0.05 to 50% IRB. n=5–9 per group.

Abbreviations: Cst, static compliance; IRB, inspiratory resistive breathing; ctr, control; SEM, standard error of the mean.

Figure 3 The effect of tiotropium bromide on lung inflammation following 50% of IRB.

Notes: Total and macrophage counts in BALf were not affected by tiotropium inhalation prior to 50% of IRB, while neutrophil numbers were reduced by tiotropium, although remained elevated compared to ctr (A and C). Both IL-1β and IL-6 levels returned to ctr values after inhalation of tiotropium (B and D). Data presented as mean ± SEM. White bar, ctr; gray bar, ctr plus tiotropium; black bar, 50% of IRB and dark gray bar, 50% of IRB plus tiotropium. *P<0.05 to ctr and ^#P<0.05 to 50% of IRB. n=5–8 per group.

Abbreviations: IRB, inspiratory resistive breathing; BALf, bronchoalveolar lavage fluid; ctr, control; SEM, standard error of the mean.

Figure 4 The effect of tiotropium bromide on lung permeability and injury following 50% of IRB.

Notes: Neither total protein levels in BALf (A) nor tissue elasticity was affected by tiotropium (B). Following tiotropium inhalation, no increase in total lung injury score was noticed after 50% of IRB (C). Data presented as mean ± SEM. White bar, ctr; gray bar, ctr plus tiotropium; black bar, 50% of IRB and dark gray bar, 50% of IRB plus tiotropium. *P<0.05 to ctr and ^#P<0.05 to 50% of IRB. n=5–8 per group.
Abbreviations: IRB, inspiratory resistive breathing; BALf, bronchoalveolar lavage fluid; SEM, standard error of the mean; ctr, control; au, arbitrary unit.

Table 3 Effect of tiotropium on respiratory system mechanics after 6 h of 60% ERB

	ctr	ctr+tiotropium	60% ERB	60% ERB+tiotropium
Rn (cm H2O·s/mL)	0.04±0.00	0.05±0.01	0.04±0.00	0.04±0.01
G (cm H2O/mL)	0.45±0.04	0.48±0.05	0.47±0.02	0.43±0.02
H (cm H2O/mL)	2.03±0.16	2.08±0.24	2.09±0.08	1.85±0.06
Cst (mL/cm H2O)	0.68±0.06	0.71±0.09	0.61±0.02	0.69±0.02
Hysteresis (cm H2O·mL)	2.85±0.15	3.33±0.37	3.47±0.15*	2.73±0.15#

Notes: R_n, Newtonian resistance of the airways; G, tissue viscance (viscous dissipation of energy) and H, tissue elasticity. Data presented as mean ± SEM.

* P<0.05 to ctr and

# P<0.05 to 60% ERB. n=6–8 per group.

Abbreviations: Cst, static compliance; ERB, expiratory resistive breathing; ctr, control; SEM, standard error of the mean.

Figure 5 The effect of tiotropium bromide on lung inflammation following 60% of ERB.

Notes: Macrophage count in BALf remained reduced compared to ctr after tiotropium inhalation. Instead, the increase in neutrophil number after 60% of ERB was attenuated by tiotropium (C), resulting in an overall reduction of total cell number (A). Tissue protein levels of both IL-1β and IL-6 returned to ctr values following tiotropium inhalation (B and D). Data presented as mean ± SEM. White bar, ctr; gray bar, ctr plus tiotropium; black bar, 60% of ERB and dark gray bar, 60% of ERB plus tiotropium. *P<0.05 to ctr and ^#P<0.05 to 60% of ERB. n=5–8 per group.

Abbreviations: ERB, expiratory resistive breathing; BALf, bronchoalveolar lavage fluid; IL, Interleukin; ctr, control; SEM, standard error of the mean.

Figure 6 The effect of tiotropium bromide on lung permeability and injury following 60% of ERB.

Notes: Total protein levels in BALf after 60% of ERB was not affected by tiotropium (A). Respiratory system elasticity was not affected by 60% of ERB (B). Finally, following tiotropium inhalation, the increase in total lung injury score after 60% of ERB was attenuated (C). Data presented as mean ± SEM; White bar, ctr; gray bar, ctr plus tiotropium; black bar, 60% of ERB and dark gray bar, 60% of ERB plus tiotropium, *P<0.05 to ctr and ^#P<0.05 to 60% of ERB. n=5–9 per group.
Abbreviations: ERB, expiratory resistive breathing; BALf, bronchoalveolar lavage fluid; SEM, standard error of the mean; ctr, control; au, arbitrary unit.

Table 4 Effect of tiotropium on respiratory system mechanics after 6 h of 40%/60% CRB

	ctr	ctr+tiotropium	40%/60% CRB	40%/60% CRB+tiotropium
Rn (cm H2O·s/mL)	0.05±0.00	0.05±0.00	0.05±0.00	0.05±0.00
G (cm H2O/mL)	0.49±0.01	0.49±0.02	0.53±0.02	0.53±0.02
H (cm H2O/mL)	2.41±0.12	2.34±0.06	2.73±0.07*	2.59±0.12
Cst (mL/cm H2O)	0.59±0.02	0.58±0.01	0.51±0.02*	0.54±0.03
Hysteresis (cm H2O·mL)	3.66±0.21	3.54±0.16	3.97±0.43	3.30±0.25

Notes: R_n, Newtonian resistance of the airways; G, tissue viscance (viscous dissipation of energy) and H, tissue elasticity. Data presented as mean ± SEM.

* P<0.05 to ctr. n=6–8 per group.

Abbreviations: CRB, combined resistive breathing; Cst, static compliance; ctr, control; SEM, standard error of the mean.

Figure 7 The effect of tiotropium bromide on lung inflammation following 40%/60% of CRB.

Notes: Tiotropium inhalation prior to 40%/60% of CRB significantly attenuated the increase in total cell number in BALf (A), by reducing both macrophage and neutrophil counts (C). Tissue protein levels of IL-1β and IL-6 returned to ctr values following tiotropium inhalation (B and D). Data presented as mean ± SEM. White bar, ctr; gray bar, ctr plus tiotropium; black bar, 40%/60% of CRB and dark gray bar, 40%/60% of CRB plus tiotropium. *P<0.05 to ctr and ^#P<0.05 to 40%/60% of CRB. n=5–8 per group.

Abbreviations: CRB, combined resistive breathing; BALf, bronchoalveolar lavage fluid; ctr, control; SEM, standard error of the mean.

Figure 8 The effect of tiotropium bromide on lung permeability and injury following 40%/60% of CRB.

Notes: Tiotropium bromide inhalation attenuated the increase in total protein in BALf after CRB (A). In addition, following tiotropium inhalation, respiratory system elasticity was not increased after 40%60% of CRB (B) and the increase in total lung injury was not noticed (C). Data presented as mean ± SEM. White bar, ctr; gray bar, ctr plus tiotropium; black bar, 40%/60% of CRB and dark gray bar, 40%/60% of CRB plus tiotropium. *P<0.05 to ctr and ^#P<0.05 to 40%/60% of CRB. n=5–10 per group.
Abbreviations: CRB, combined resistive breathing; BALf, bronchoalveolar lavage fluid; SEM, standard error of the mean; ctr, control; au, arbitrary unit.