Effects of different cold-air exposure intensities on the risk of cardiovascular disease in healthy and hypertensive rats

• Published in: International journal of biometeorology 2014-03, Vol.58 (2), p.185-194
• Main Authors: Luo, Bin, Zhang, Shuyu, Ma, Shoucun, Zhou, Ji, Wang, Baojian
• Format: Article
• Language: English
• Subjects: Air; Air exposure; Air temperature; Animal Physiology; Animals; Atherosclerosis - physiopathology; Biological and Medical Physics; Biophysics; blood; blood lipids; Blood Pressure; blood viscosity; Body Temperature; Body weight; Cardiovascular diseases; climate; Earth and Environmental Science; Environment; Environmental Exposure; Environmental Health; fibrinogen; Health risks; high density lipoprotein; Hypertension; Hypertension - physiopathology; ICB 2011 - Students; Lipids; low density lipoprotein; Male; Meteorology; New Professionals; Plant Physiology; Rats; Rats, Inbred SHR; Rats, Wistar; risk; Risk Factors; Rodents; systolic blood pressure; temperature
• ISSN: 0020-7128; 1432-1254
• DOI: 10.1007/s00484-013-0641-3

Ten-week-old male Wistar rats (systolic blood pressure, 106–116 mmHg; body weight, 300–320 g) and spontaneously hypertensive rats (systolic blood pressure, 160–176 mmHg; body weight, 210.9–244.9 g) were used as healthy and hypertensive subjects to determine the effects of varying degrees of cold-air exposure in a climate chamber box. The three cold-air ranks were cold air I [minimum temperature (TMIN) 6.4 °C, ↓∆T₄₈ 8.6 °C], cold air II (TMIN 3.8 °C, ↓∆T₄₈ 11.2 °C), and cold air III (TMIN −0.3 °C, ↓∆T₄₈ 15.3 °C), as established from the cold-air data of Zhangye City, China. Each cold-air rank consisted of a temperature drop and a temperature increase with the same initial and terminal temperatures (15 °C). After cold-air exposure, the risk factors for cardiovascular disease (CVD) such as systolic blood pressure, whole blood viscosity (10/s and 150/s), plasma fibrinogen, and blood lipids of the rats were determined. The results indicated that the CVD risk factors of the healthy and hypertensive rats increased significantly with cold-air exposure intensities. The increase in systolic blood pressure was greater during temperature drops, whereas the increases in whole blood viscosity and plasma fibrinogen were greater after cold-air exposure. The effects of cold-air exposure on the CVD risk factors of healthy rats, particularly the systolic blood pressure, whole blood viscosity (150/s), and LDL/HDL, were greater than those in hypertensive rats. In conclusion, CVD risk may increase with cold-air ranks. Blood pressure-induced CVD risk may be greater during cold-air temperature drop, whereas atherosclerosis-induced CVD risk may be greater after cold-air exposure. The effect of cold air on the CVD risk factors in healthy subjects may be more significant than those in hypertensive subjects.