| Aims: To investigate the effects of early captopril treatment on blood pressure,vascular structure and function of thoracic aortae and 3rd grade branch mesenteric arteries in spontaneously hypertensive rats(SHR)and Wistar-Kyoto(WKY)rats.Methods: SHR and WKY rats were divided into four groups respectively: untreated SHR/WKY(SHRUn/WKYUn),prenatal captopril-treated SHR/WKY(SHRPre/WKYPre),postnatal captopril-treated SHR/WKY(SHRPost/WKYPost),sequential captopril-treated SHR/WKY(SHRSeq/WKYSeq).SHRPre,SHRPost,SHRSeq,WKYPre,WKYPost and WKYSeq groups were considered as early treament groups.SHRUn and WKYUn: both maternal rats and offspring rats were not given captopril treatment;SHRPre and WKYPre: maternal rats were administrated with captopril only during the pregnancy;SHRPost and WKYPost: maternal rats received captopril treatment during the lactation,and the offspring continued to receive captopril treatment after weaning until they were 16 weeks old;SHRSeq and WKYSeq: maternal rats were administrated with captopril throughout the pregnancy and lactation,and the offspring continued to receive captopril treatment after weaning until they were 16 weeks old.Captopril was administrated once daily by gavage at the dose of 30mg/kg/d.8 and 16 weeks old male offspring rats were used to be experimental animals with 8 rats in each group.Systolic blood pressure(SBP)was measured by tail-cuff method at 8 and 16 weeks old.The wall-to-lumen area ratios(WA%)and the ratios of wall thickness to lumen radius(WT%)of thoracic aortae and 3rd grade branch mesenteric arteries were assessed after HE staining.Endothelium-dependent relaxation(EDd R),endothelium-independent relaxation(EDi R),vasoconstrictive function(VCF)were measured by Power Lab biological signal analytic system.Results:1.At 8 and 16 weeks old,SBP levels in SHRPre,SHRPost and SHRSeq were significantly decreased compared with SHRUn [SBP/mm Hg: 8Wks,(SHRPre128.85±10.88),(SHRPost119.52 ±9.46),(SHRSeq121.73±10.29)vs.(SHRUn152.73±9.77);16Wks,(SHRPre 180.10±8.06),(SHRPost139.46±4.26),(SHRSeq138.92 ±8.82)vs.(SHRUn204.92 ±16.00),all P<0.05].There was no significant difference in SBP among SHRPre,SHRPost and SHRSeq at 8 weeks of age(P>0.05).But at 16 weeks of age,it was significantly higher in SHRPre than SHRPost and SHRSeq(P<0.05),and no significant difference was oberserved between SHRPost and SHRSeq(P>0.05).2.At 8 weeks of age,there was no significant difference in WA% and WT% of the thoracic aortae and the 3rd grade branch mesenteric arteries among SHR groups(P>0.05).At 16 weeks of age,the WA% and WT% of the thoracic aortae and the 3rd grade branch mesenteric arteries were significantly lower in SHRPre,SHRPost and SHRSeq than those in SHRUn(P<0.05),and there was no statistically significant difference among SHRPre,SHRPost and SHRSeq(P>0.05).3.At 8 weeks of age,there was no significant difference in the EDd R and EDi R of the thoracic aortae among SHR groups(P>0.05).At 16 weeks of age,the EDd R and EDi R of the thoracic aortae were significantly higher in SHRPre,SHRPost and SHRSeq compared with SHRUn [PD2: EDd R,(SHRPre5.89±0.35),(SHRPost5.96±0.35),(SHRSeq5.94±0.41)vs.(SHRUn5.45±0.11);EDi R,(SHRPre6.52±0.23),(SHRPost6.54±0.24),(SHRSeq6.57±0.21)vs.(SHRUn6.17±0.14),all P<0.05],and there were no significant difference among SHRPre,SHRPost and SHRSeq(P>0.05).4.At 8 weeks of age,there was no significant difference in the EDd R and EDi R of the 3rd grade branch mesenteric arteries among SHR groups(P>0.05).At 16 weeks of age,the EDd R and EDi R of the 3rd grade branch mesenteric arteries were significantly higher in SHRPre,SHRPost and SHRSeq than SHRUn [PD2: EDd R,(SHRPre5.24±0.36),(SHRPost5.28±0.31),(SHRSeq5.38±0.38)vs.(SHRUn4.36±0.46);EDi R,(SHRPre6.18±0.33),(SHRPost6.37±0.35),(SHRSeq6.26±0.31)vs.(SHRUn5.81±0.13),all P<0.05],and there were no significant difference among SHRPre,SHRPost,SHRSeq(P>0.05).5.The VCF of the thoracic aortae and 3rd grade branch mesenteric arteries in the captopril treament groups of SHR was not different from that of SHRUn at 8 weeks or 16 weeks(P>0.05).6.There was no significant difference in blood pressure between WKYPre and WKYUn at 8 weeks and 16 weeks(P>0.05),while blood pressure in WKYUn was significantly higher than WKYPost and WKYSeq(P<0.05).7.Regardless of the 8-week or 16-week-old,there was no significant difference in WA% and WT% of the thoracic aortae and 3rd grade branch mesenteric arteries between the early treament groups of WKY and the WKYUn(P>0.05).And there was also no significant difference in systolic/diastolic function of thoracic aortae and 3rd grade branch mesenteric arteries among WKY groups(P>0.05).Conclusions: 1.Early treatment of SHR with captopril could persistently postpone the increase in BP,inhibit vascular remodeling,improve EDd R function and EDi R function.2.Prenatal captopril treatment had no effect on blood pressure,vascular structure and function of WKY rats. |
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