Standard protocol for measuring blood pressure

Systolic blood pressure is measured in conscious mice using a BP-2000 Blood Pressure Analysis tail cuff system from Visitech Systems, Inc (Apex, NC).  Prior to testing, the inflation pressure is calibrated using a mercury manometer and the heated platform is checked with a surface thermometer to verify uniform heating to 34° ±  0.5 ° C. In our experience, heating the platform to 38°C [Krege, Sugiyama] causes some mice to sweat and increases mouse movement, resulting in fewer valid blood pressure measurements.

Mice are brought to the testing room, in which the lights are dimmed, and allowed to acclimatize for 20 minutes prior to testing. Mice are placed on the blood pressure platform and held in place with an opaque restraining chamber that is open at the front and has a notch at the back for the tail. Tails are threaded through balloon cuffs and placed in a groove containing a light source and photoresistor for measuring tail blood flow.

Blood pressure is measured during 30 consecutive, computer-automated inflation/deflation cycles of the balloon cuff (10 preliminary measurements and 20 test measurements). Data from the preliminary measurements are discarded and data from the test measurements are averaged. The mean systolic blood pressure (mm Hg) and pulse rate (beats per minute) from the 20 test measurements is taken as the blood pressure and pulse rate for each mouse. Blood pressure values below 60 mm Hg on individual test measurements are not included in the average since they likely result from failure of the machine to detect the pulse of the mouse (probably due to excessive mouse movement) [Sugiyama, Lorenz]. Variability in testing conditions is minimized by measuring all mice within a strain at the same time (i.e., in groups of four one after the other until all mice are tested) and by having the same technician measure all mice within a strain.

If a test session yields fewer than 10 valid blood pressure measurements (out of 20 measurements total) or if the standard deviation of valid test measurements is greater than 20% of the mean, blood pressure measurements are repeated one time.

Representative normative data

The following base line data was generated in the In Vivo laboratory and deposited in the Mouse Phenome Database. Please visit http://phenome.jax.org/pub-cgi/phenome/mpdcgi?rtn=docs/home and search on JAXWest1 for the complete data set.

C57BL/6J, DBA/2J, AND BALB/cJ mice were obtained from the Sacramento, CA facility (maximum barrier); all other strains obtained from the Bar Harbor, ME facility (standard barrier). Animals shipped from Bar Harbor were allowed to acclimate for 7 days except for SJL/J which was shipped at 4 weeks of age and then held at Sacramento for an additional 5 weeks. Animals were tested at between 9-14 weeks of age

Customized options

  • Measurements before and after compound administration
  • Repeated measurements over several days to test acclimatization
  • Multiple measurements over time to test diet or long-term compound effects

References

Krege JH, Hodgin JB, Hagaman JR, Smithies O. A noninvasive computerized tail-cuff system for measuring blood pressure in mice. Hypertension 1995;25(5):1111-5 [PubMed: 7737724].

Sugiyama F, Churchill GA, Li R, Libby LJ, Carver T, Yagami K, John SW, Paigen B. QTL associated with blood pressure, heart rate, and heart weight in CBA/CaJ and BALB/cJ mice. Physiol Genomics. 2002;10(1):5-12 [PubMed: 12118100].

Lorenz JN.  A practical guide to evaluating cardiovascular, renal, and pulmonary function in mice. Am J Physiol Regul Integr Comp Physiol. 2002;282(6):R1565-82 [PubMed: 12010737].