Hypertension model in rats

Spontaneously Hypertensive Rats (SHRs) is the best-investigated animal model of essential (or primary) hypertension used to study and treat cardiovascular disease. SH rats develop hypertension at the age of 5-6 weeks. Between 40 and 50 weeks, SHRs exhibit signs of vascular and cardiac hypertrophy, providing a classic model for studying the efficacy of new cardioprotective agents. 

The dynamics of diastolic blood pressure in SHR rats at different time-points after single PO administration of vehicle (20% Captisol) or Prazosine at a dose of 3 mg/kg (M±SD). Rats are placed in plastic holders set on the warming platform for 10 min to achieve stress-reducing and the tail temperature of 32-34°C before the testing. Systolic and diastolic blood pressure (BP) were measured. Mean BP and pulse pressure (PP, difference between systolic and diastolic BP) values were then calculated.

Service details: A standard study design includes at least 3 groups of rats (vehicle dosed, treated with reference compound, and tested compound treated group), 5-10 rats per group, 7 days of acclimatization period, 3-4 weeks of the treatment period, and 7 days of testing and post-treatment observation. Blood pressure is measured in the tail of a rat using volume pressure recording sensor technology with the CODA (Kent Scientific, USA) rat tail-cuff system. Rats treatment procedures include invasive (by IV, IP, SC routes), and non-invasive (PO route, and diet incorporated) routes of drug administration. Gross necropsy is performed on all animals at the endpoint. Specific tests, such as hematological, urinary, and blood clinical chemistry analysis, food and water intake, histopathology, etc. in combination with more definitive toxic or gross pathology endpoints are available on request.

Angiotensin-induced hypertension in rats 

Angiotensin II (Ang II) is an important contributor to blood pressure regulation and plays a significant role in hypertension development and in the pathophysiology of all the related processes and complications.  Ang II infusion causes immediate systemic hypertension in normotensive rats, which provides a suitable short-term model to evaluate antihypertensive activities of the drugs. 

The mean blood pressure (BP) in male Wistar rats subjected to Ang II infusion (500 ng/kg/min) after single PO administration of vehicle (10% DMSO) or Valsartan at a dose of 20 mg/kg compared to baseline. Rats are placed in soft holders  setting on the warming platform for 10 min to reduce stress and achieve a tail temperature of 32-34°C before the testing. Simultaneously, Ang II infusion is performed through jugular vein catheter. Systolic and diastolic BP are recorded. Mean BP and pulse pressure (difference between systolic and diastolic BP) values are then calculated. 

Service details: A standard study design includes at least 3 groups of rats (vehicle-dosed, treated with reference compound, and tested compound treated group), 7 days of acclimatization period, 3 days for jugular vein catheter installation and subsequent animal recovery, and 1 day of measurements. Depending on the tested compound’s properties, animals’ treatment before the final measurements can continue up to 7 days or as required. Blood pressure is measured in the tail of a rat using volume pressure recording sensor technology with the CODA (Kent Scientific, USA) rat tail-cuff system. Rats treatment procedures include invasive (by IV, IP, SC routes), and non-invasive (PO route, and diet incorporated) routes of drug administration. Gross necropsy is performed on all animals at the endpoint. Specific tests, such as hematological, urinary, and blood clinical chemistry analysis, food and water intake, histopathology, etc. in combination with more definitive toxic or gross pathology endpoints are available on request.