STRUCTURAL ALTERATIONS OF RESISTANCE VESSELS OF SPONTANEOUSLY HYPERTENSIVE RATS AND PROTECTIVE EFFECTS OF CAPTOPRIL

摘要

Objective. To observe the structural alterations of resistance vessels in spontaneously hypertensive rats (SHRs) and to evaluate the effects of captopril on them. Methods. 15-week-old male SHRs were treated with oral captopril (100mg/ kg/ day) for 12 weeks. Age-and sex-matched SHRs and Wistar-Kyoto rats (WKY) were fed under the same conditions without captopril administration for the same duration. All rats were killed at the age of 27 weeks. The structural parameters included media width, lumen diameter, media-lumen ratio, vascular collagen area (VCA) and vascular collagen density (VCD). The media width, lumen diameter and media-lumen ratio were measured in hhematoxylin and eosin staining sections under a direct light microscope and VCA and VCD in picrosirius red st aining sections under a polarizing light microscope. All the values were processed with a computer image analyzer. Results. There were thicker media width, smaller lumen diameter, higher media-lumen ratio and larger VCA in untreated SHRs than in WKY. Captopril inhibited media thickening, with lumen diameter decreasing, media-lumen ratio increasing and VCA enlarging. There was no significant difference in VCD among the three groups. Conclusions. Adverse structural alterations occur in resistance vessels of SHRs and captopril may prevent their progression.