title: Effects of different cold-air exposure intensities on the risk of cardiovascular disease in healthy and hypertensive rats.
abstract: 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.
authors: School of Applied Meteorology, Nanjing University of Information Science and Technology, 219 Ningliulu, Nanjing, China.
authors: Bin
authors: B
authors: Luo
authors: Shuyu
authors: S
authors: Zhang
authors: Shoucun
authors: S
authors: Ma
authors: Ji
authors: J
authors: Zhou
authors: Baojian
authors: B
authors: Wang
mesh_terms: D000388:Air; D000818:Animals; D050197:Atherosclerosis / Q000503:physiopathology*; D001794:Blood Pressure; D001831:Body Temperature; D004781:Environmental Exposure; D006973:Hypertension / Q000503:physiopathology*; D008297:Male; D051381:Rats; D011918:Rats, Inbred SHR; D017208:Rats, Wistar; D012307:Risk Factors