Does unrestrained single-chamber plethysmography provide a valid assessment of airway responsiveness in allergic BALB/c mice?
BACKGROUND
Unrestrained plethysmography has been used to monitor bronchoconstriction because of its ease of use and ability to measure airway responsiveness in conscious animals. However, its reliability remains controversial.


OBJECTIVE
To investigate if unrestrained plethysmography could provide a valid interpretation of airway responsiveness in allergic BALB/c mice.


METHODS
Ovalbumin sensitized BALB/c mice were randomized to receive either a single-dose Ovalbumin challenge (OVA-1D group) or a three-dose Ovalbumin challenge (OVA-3D group). The OVA-1D group was further divided into OVA-1D-I (measured invasively, using lung resistance as the index of responsiveness) and OVA-1D-N group (measured non-invasively, using Penh as the index of responsiveness). Similarly the OVA-3D group was divided into OVA-3D-I and OVA-3D-N groups based on the above methods. The control groups were sensitized and challenged with normal saline. Bronchial alveolar lavage fluid was taken and airway histopathology was evaluated for airway inflammation. Nasal responsiveness was tested with histamine challenge.


RESULTS
Compared with controls, a significant increase in airway responsiveness was shown in the OVA-1D-N group (P < 0.05) but not in the OVA-1D-I group. Both OVA-3D-I and OVA-3D-N groups showed higher responsiveness than their controls (P < 0.05). The nasal mucosa was infiltrated by eosinophic cells in all Ovalbumin immunized groups. Sneezing or nasal rubbing in allergic groups appeared more frequent than that in the control groups.


CONCLUSIONS
Penh can not be used as a surrogate for airway resistance. The invasive measurement is specific to lower airway. Penh measurement (done as a screening procedure), must be confirmed by a direct invasive measurement specific to lower airway in evaluating lower airway responsiveness.
Zhang
Qingling
Q
State Key Laboratory of Respiratory Disease (Guangzhou Medical University), The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, PR China. Dr.zhang68@yahoo.com
Lai
Kefang
K
Xie
Jiaxing
J
Chen
Guoqin
G
Zhong
Nanshan
N
D000281:Administration, Intranasal; D000403:Airway Resistance; D000818:Animals; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D004804:Eosinophils / Q000502:physiology; D005260:Female; D006632:Histamine; D007249:Inflammation / Q000473:pathology; D007274:Injections, Intraperitoneal; D051379:Mice; D008807:Mice, Inbred BALB C; D009297:Nasal Mucosa / Q000473:pathology; D010047:Ovalbumin / Q000008:administration & dosage / Q000276:immunology; D010991:Plethysmography / Q000295:instrumentation* / Q000379:methods; D012130:Respiratory Hypersensitivity / Q000175:diagnosis* / Q000503:physiopathology*; D012137:Respiratory System / Q000503:physiopathology*; D012912:Sneezing
D006632:Histamine; D010047:Ovalbumin