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Does unrestrained single-chamber plethysmography provide a valid assessment of airway responsiveness in allergic BALB/c mice?

Zhang Q, Lai K, Xie J, Chen G, Zhong N - Respir. Res. (2009)

Bottom Line: 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.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.

View Article: PubMed Central - HTML - PubMed

Affiliation: State Key Laboratory of Respiratory Disease (Guangzhou Medical University), The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, PR China. Dr.zhang68@yahoo.com

ABSTRACT

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.

Conclusion: 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.

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Light microscopic images of the murine nose (50 fold magnification) of a coronal section through the sinonasal skeleton, showing the murine nasal anatomy. Eosinophils were counting in a defined region of the nasal mucosa (along red line).
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Figure 2: Light microscopic images of the murine nose (50 fold magnification) of a coronal section through the sinonasal skeleton, showing the murine nasal anatomy. Eosinophils were counting in a defined region of the nasal mucosa (along red line).

Mentions: After AR measurements by Penh measurements, the mice were skinned, fixed for 48 h in buffered formalin (10%) at 20 degrees Celsius and decalcified during 2 weeks using a 14% ethylenediamineteraacetic acid (Sigma, USA) solution. Coronal sections of the skulls in the middle and the third between nose-tip and orbit were made and stored in formalin until further processing. After dehydration and embedding in paraffin, a thickness of 4 μm, the specimens were then deparaffinized and stained with hematoxylin-eosin. Representative nasal sections were scored by counting eosinophils in (sub)-epithelial layers of both lateral nasal walls by using an eyepiece reticule. The number of eosinophils was quantified per unit (1 mm2) of lateral nasal walls length (between the lower edge of the upper turbinate and the upper edge of the middle turbinate; the lower edge of the middle turbinate and the upper edge of the lower turbinate; the lower edge of the lower turbinate and nose-tip) (Figure 2). The data were obtained from nine to ten mice per group after AR measurement by non-invasive approach.


Does unrestrained single-chamber plethysmography provide a valid assessment of airway responsiveness in allergic BALB/c mice?

Zhang Q, Lai K, Xie J, Chen G, Zhong N - Respir. Res. (2009)

Light microscopic images of the murine nose (50 fold magnification) of a coronal section through the sinonasal skeleton, showing the murine nasal anatomy. Eosinophils were counting in a defined region of the nasal mucosa (along red line).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2719610&req=5

Figure 2: Light microscopic images of the murine nose (50 fold magnification) of a coronal section through the sinonasal skeleton, showing the murine nasal anatomy. Eosinophils were counting in a defined region of the nasal mucosa (along red line).
Mentions: After AR measurements by Penh measurements, the mice were skinned, fixed for 48 h in buffered formalin (10%) at 20 degrees Celsius and decalcified during 2 weeks using a 14% ethylenediamineteraacetic acid (Sigma, USA) solution. Coronal sections of the skulls in the middle and the third between nose-tip and orbit were made and stored in formalin until further processing. After dehydration and embedding in paraffin, a thickness of 4 μm, the specimens were then deparaffinized and stained with hematoxylin-eosin. Representative nasal sections were scored by counting eosinophils in (sub)-epithelial layers of both lateral nasal walls by using an eyepiece reticule. The number of eosinophils was quantified per unit (1 mm2) of lateral nasal walls length (between the lower edge of the upper turbinate and the upper edge of the middle turbinate; the lower edge of the middle turbinate and the upper edge of the lower turbinate; the lower edge of the lower turbinate and nose-tip) (Figure 2). The data were obtained from nine to ten mice per group after AR measurement by non-invasive approach.

Bottom Line: 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.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.

View Article: PubMed Central - HTML - PubMed

Affiliation: State Key Laboratory of Respiratory Disease (Guangzhou Medical University), The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, PR China. Dr.zhang68@yahoo.com

ABSTRACT

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.

Conclusion: 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.

Show MeSH