Effect of artificial cold exposure on the blood pressure of rats with carotid atherosclerosis

Abstract

Objective To study the effect of artificial cold exposure （ACE） on the level of blood pressure in carotid atherosclerotic rats, and the prophylactic effect of nimodipine on it. Methods One hundred and thirty SD rats were randomly divided into normal group （n=10）, sham-operated group （n=10）, and carotid atherosclerotic （CAS） group （n=110）. High-fat diet was given to the sham-operated group and CAS group; normal diet was given to the control group. Then, 105 alive rats in the CAS group were further sub-divided into non-ACE group （n=40）, ACE group （n=38） and nimodipine treatment group （n=37）. All the groups were subjected to ACE for 3 d except non-ACE group, and kept at 22 °C throughout the experiment. During the ACE, an intragastric administration of nimodipine was given to the nimodipine treatment group. The changes of the blood pressure before and after ACE were analyzed and compared. Results The level of pre-ACE blood pressure in the sham-operated group and CAS group was significantly higher than that in the normal group （P〈0.05）. The level of post-ACE blood pressure was significantly increased in the normal group, sham-operated group and ACE group, and significantly decreased in the nimodipine treatment group as compared with the level of pre-ACE one in these groups （P〈0.05）. No significant differences were noted between the levels of pre-ACE and post-ACE blood pressure in the normal group, sham-operated group and ACE group （P〉0.05）. The level of post-ACE blood pressure in rats treated with nimodipine was obviously decreased as compared with that in the ACE group （P〈0.05）. Conclusion ACE could increase the level of blood pressure in carotid atherosclerotic rats and this effect might be lessoned by the administration of nimodipine. Key words: Artificial cold exposure; Carotid atherosclerosis; Blood pressure; Nimodipine