Nomenclature: SHR/NHsd
SHR Inbred Rat Origin
- The SHR inbred rat was derived from a nucleus colony obtained
from the National Institutes of Health, Bethesda, Maryland.
SHR Inbred Rat Characteristics
- Coat: Albino
- Spontaneous hypertension
- Insulin resistant
- Hyperactive
SHR Inbred Rat Research
Use
Harlan Laboratories Production
Procedure for Blood Pressure
Monitoring
To maintain the phenotype of SHR/NHsd rats, Harlan Laboratories
routinely screens future breeders for acceptable blood pressure
levels. Procedures vary slightly between colonies in Europe
and North America.
Europe
Future breeders are tested after 10 weeks of age. Females
must have a pressure >180 mm/Hg. Males must have a
pressure >200 mm/Hg. Inventory animals are not
commercially monitored unless requested by the customer.
North America
Future breeders (either sex) must have a pressure of
>180 mm/Hg. In addition, the blood pressure is monitored
on rats entering commercial inventory greater than eight (8) weeks
of age.
By individual customer request, animals shipping younger than eight
(8) weeks of age can have their blood pressure monitored prior to
shipment.
Procedures
To monitor blood pressure, Harlan Laboratories utilizes the tail
cuff method with a non-invasive blood pressure monitor. Prior to
blood pressure measurement, animals are placed in a cage with a
heat lamp for approximately 20 minutes and then transferred to a
restraint cylinder appropriate for their size with a heat
source(82-88° F, 28-31°C) to elevate their ambient
temperature and vasodilate the vascular system in the
tail. After warming the rats, the occlusion and sensor cuff is
placed on the tail. Measurement begins when the animal becomes
acclimated to its surroundings and stops moving, with the tail
remaining immobile during measurement. Three successful
measurements are taken with the median measurement
recorded. Future breeders are selected based on meeting a
minimum pressure level.
Normal Values
Because differences in blood pressure can be seen with different
equipment used, the normal values for animals is different between
different colonies, and will vary from the published
literature. Customers should also expect some differences in
measurements taken using their own
methods.
Animals 6-7 weeks of age are typically 140 mmHg
Animals 8-13 weeks of age are typically 160 mmHg
Animals 14-15 weeks of age are typically greater than 180 mmHg