Effects of Rho-kinase inactivation on eosinophilia and hyper-reactivity in murine airways by allergen challenges.
BACKGROUND
A small GTPase, Rho, and its target molecule, Rho-kinase, play an important role in the cell functions, including contractility, chemotaxis, adhesion, and migration. It is generally considered that eosinophilic inflammation and hyper-reactivity to methacholine in airways are fundamental to the pathophysiology of bronchial asthma.


OBJECTIVE
This study was designed to determine whether the Rho/Rho-kinase pathways are involved in the eosinophil recruitment and airway hyper-reactivity. We investigated inhibitory effects of fasudil, a specific inhibitor of Rho-kinase, on acute allergic inflammation in mice.


METHODS
BALB/c mice were sensitized and challenged with ovalbumin (OVA). OVA-challenged mice were treated orally with fasudil (3, 10, 30 mg/kg) or saline before each OVA challenge. Total cell counts, differential cell counts, cytokines, and chemokines levels were measured in bronchoalveolar lavage (BAL), and lungs were examined histologically. Moreover, respiratory resistance in response to methacholine was measured.


RESULTS
When fasudil was administrated to OVA-challenged mice, increased cell numbers of total cells and eosinophils were significantly attenuated in a dose-dependent manner. However, inflammatory cells other than eosinophils were not affected by fasudil. Fasudil caused a dose-dependent inhibition in increased levels of IL-5, IL-13, and eotaxin in BAL fluid by OVA challenges. Histological analysis of the airways revealed that both infiltration of inflammatory cells and goblet cell hyperplasia were significantly suppressed in fasudil treatment. Furthermore, fasudil significantly suppressed the augmented responsiveness to methacholine induced by OVA challenges.


CONCLUSIONS
Oral administration of fasudil inhibits eosinophil recruitment, goblet cell hyperplasia and airway hyper-reactivity by allergen challenges. These effects of this agent may be mediated by suppressing a chemokine and cytokines related to the pathophysiology of bronchial asthma such as eotaxin, IL-5, and IL-13. Our findings provide evidence that inhibition of the Rho/Rho-kinase pathway may be beneficial for bronchial asthma.
Taki
F
F
Department of Respiratory Medicine, Nagoya University Graduate School of Medicine, Nagoya, Japan.
Kume
H
H
Kobayashi
T
T
Ohta
H
H
Aratake
H
H
Shimokata
K
K
D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine / Q000031:analogs & derivatives* / Q000627:therapeutic use; D000485:Allergens; D000818:Animals; D016535:Bronchial Hyperreactivity / Q000201:enzymology / Q000276:immunology / Q000517:prevention & control*; D001985:Bronchial Provocation Tests; D001992:Bronchoalveolar Lavage Fluid / Q000276:immunology; D054413:Chemokine CCL11; D019742:Chemokines, CC / Q000096:biosynthesis; D004305:Dose-Response Relationship, Drug; D004353:Drug Evaluation, Preclinical; D004802:Eosinophilia / Q000201:enzymology / Q000276:immunology / Q000517:prevention & control*; D005260:Female; D007378:Interleukins / Q000096:biosynthesis; D047908:Intracellular Signaling Peptides and Proteins / Q000037:antagonists & inhibitors*; D051379:Mice; D008807:Mice, Inbred BALB C; D009093:Mucus / Q000378:metabolism; D010047:Ovalbumin; D047428:Protein Kinase Inhibitors / Q000627:therapeutic use*; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors*; D054460:rho-Associated Kinases
D000485:Allergens; C515457:Ccl11 protein, mouse; D054413:Chemokine CCL11; D019742:Chemokines, CC; D007378:Interleukins; D047908:Intracellular Signaling Peptides and Proteins; D047428:Protein Kinase Inhibitors; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D010047:Ovalbumin; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases; C049347:fasudil