Standard protocol for respiratory test

Respiratory function is measured in conscious, freely moving mice using whole body plethysmographs (WBP) from BUXCO Electronics, Inc. (Troy, NY). WBP chambers allow animals to move freely within the chamber while respiratory function is measured. Six chambers are used simultaneously so that six mice can be measured at the same time.

Each WBP chamber is connected to a bias flow regulator to supply a smooth, constant flow of fresh air during testing. A transducer attached to each chamber detects pressure changes that occur as the animal breathes. Pressure signals are amplified by a MAX II Strain Gauge preamplifier and analyzed by the Biosystem XA software supplied with the system (BUXCO Electronics, Inc.). Pressure changes within each chamber are calibrated prior to testing by injecting exactly 1 ml of air through the injection port and adjusting the computer signal accordingly.

Mice are placed in the WBP chambers and allowed to acclimate for 10 minutes prior to testing. Testing is conducted by letting the animals move and breathe freely for 15 minutes while the following parameters are measured: Tidal Volume (ml), Respiratory Rate (breaths per minutes), Minute Volume (tidal volume multiplied by respiratory rate, ml/min), Inspiratory Time (sec), Expiratory Time (sec), Peak Inspiratory Flow (ml/sec), and Peak Expiratory Flow (ml/sec). Raw data for each of the parameters listed above are captured in the software database and averaged once per minute to give a total of 15 data points per parameter (except for Accumulated Volume—see below). The average of the 15 data points is reported. Accumulated Volume (ml) is a cumulative value (not averaged) and represents the sum of all tidal volumes for the 15-minute test session.

The protocol can be customized to include measurements before, during, and after methacholine challenge to determine Penh or other parameters of interest. Contact JAX® Services for more information.

Customized options

  • Measurements before and after compound administration
  • Allergen sensitization with ovalbumin
  • Respiratory challenge with nebulized methacholine
  • Longer testing times

References

Tankersley CG, Fitzgerald RS, Kleeberger SR. Differential control of ventilation among inbred strains of mice. Am. J. Physiol. 1994; 267:R1372-R1377 [PubMed: 7977867].

Hamelmann E, Schwarze J, Takeda K, Oshiba A, Larsen GL, Irvin CG, and Gelfand EW. Noninvasive measurement of airway responsiveness in allergic mice using barometric plethysmography. Am. J. Respir. Crit. Care Med. 1997; 156:766-775 [PubMed: 9309991].

Petak F, Habre W, Donati YR, Hantos A, Barazzone-Argiroffo C. Hyperoxia-induced changes in mouse lung mechanics: forced oscillations vs. barometric plethysmography. J. Appl. Physiol. 2001; 90:2221-2230 [PubMed: 11356786].

Albertine KH, Wang L, Watanabe S, Marathe GK, Zimmerman GA, and Mcintyre TM. Temporal correlation of measurements of airway hyperresponsiveness in ovalbumin-sensitized mice. Am. J. Physiol. 2002; 283:L219-L233 [PubMed: 12060580].

Lundblad LKA, Irvin CG, Adler A, and Bates JHT. A reevaluation of the validity of unrestrained plethysmography in mice. J. Appl. Physiol. 2002; 93:1198-1207 [PubMed: 12235015].

Bates JHT, and Irvin, CG. Measuring lung function in mice: the phenotyping uncertainty principle. J. Appl. Physiol. 2003; 94:1297-1306 [PubMed: 12626466].

Irvin CG and Bates JHT. Measuring the lung function in the mouse; the challenge of size. BMC Respir. Res 2003; 4:4 [PubMed: 12783622].