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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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Related in: MedlinePlus

24 hours after final exposure, mice were assessed for airway responsiveness to Mch challenge. (A), (B) and (C) are OVA sensitized with single-dose OVA challenge, measured invasively (A, OVA-1D-I, squares on solid line) or by Penh measurements (non-invasively) (B, OVA-1D-N, squares on solid line). (D) and (E) are OVA sensitized with three-dose OVA challenge, measured invasively (D, OVA-3D-I, triangles on solid line) or by Penh measurements (E, OVA-3D-N, triangles on solid line). *P < 0.05 compared with controls (circles on dotted line).
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Figure 3: 24 hours after final exposure, mice were assessed for airway responsiveness to Mch challenge. (A), (B) and (C) are OVA sensitized with single-dose OVA challenge, measured invasively (A, OVA-1D-I, squares on solid line) or by Penh measurements (non-invasively) (B, OVA-1D-N, squares on solid line). (D) and (E) are OVA sensitized with three-dose OVA challenge, measured invasively (D, OVA-3D-I, triangles on solid line) or by Penh measurements (E, OVA-3D-N, triangles on solid line). *P < 0.05 compared with controls (circles on dotted line).

Mentions: 24 hours after final exposure, mice were assessed for AR by Mch challenge. The OVA-1D -I group, measured invasively for resistance, did not have an increase in AR in comparison to control mice (see Figure 3A). In contrast, the OVA-1D- N group which had the same allergen sensitization and challenge protocol as OVA-1D-I group showed a significant increase in AR at MCh concentrations of 6.25 – 25 mg/ml as measured by Penh measurements (see Figure 3B). In addition, Penh 200 and Penh 300 decreased significantly in OVA-1D- N group when compared with the control group (see Figure 3C). Both OVA-3D-N and OVA-3D-I groups presented with airway hyperresponsiveness (see Figures 3D, E). Compared with the control group, airway hyperresponsiveness in OVA-3D-N group was shown at MCh concentrations of 0.78–50 mg/ml but at MCh concentrations of 12.5 – 50 mg/ml in OVA-3D-I group.


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)

24 hours after final exposure, mice were assessed for airway responsiveness to Mch challenge. (A), (B) and (C) are OVA sensitized with single-dose OVA challenge, measured invasively (A, OVA-1D-I, squares on solid line) or by Penh measurements (non-invasively) (B, OVA-1D-N, squares on solid line). (D) and (E) are OVA sensitized with three-dose OVA challenge, measured invasively (D, OVA-3D-I, triangles on solid line) or by Penh measurements (E, OVA-3D-N, triangles on solid line). *P < 0.05 compared with controls (circles on dotted line).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 3: 24 hours after final exposure, mice were assessed for airway responsiveness to Mch challenge. (A), (B) and (C) are OVA sensitized with single-dose OVA challenge, measured invasively (A, OVA-1D-I, squares on solid line) or by Penh measurements (non-invasively) (B, OVA-1D-N, squares on solid line). (D) and (E) are OVA sensitized with three-dose OVA challenge, measured invasively (D, OVA-3D-I, triangles on solid line) or by Penh measurements (E, OVA-3D-N, triangles on solid line). *P < 0.05 compared with controls (circles on dotted line).
Mentions: 24 hours after final exposure, mice were assessed for AR by Mch challenge. The OVA-1D -I group, measured invasively for resistance, did not have an increase in AR in comparison to control mice (see Figure 3A). In contrast, the OVA-1D- N group which had the same allergen sensitization and challenge protocol as OVA-1D-I group showed a significant increase in AR at MCh concentrations of 6.25 – 25 mg/ml as measured by Penh measurements (see Figure 3B). In addition, Penh 200 and Penh 300 decreased significantly in OVA-1D- N group when compared with the control group (see Figure 3C). Both OVA-3D-N and OVA-3D-I groups presented with airway hyperresponsiveness (see Figures 3D, E). Compared with the control group, airway hyperresponsiveness in OVA-3D-N group was shown at MCh concentrations of 0.78–50 mg/ml but at MCh concentrations of 12.5 – 50 mg/ml in OVA-3D-I group.

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
Related in: MedlinePlus