PS-BPB09-4: ARTERIAL SITES AND SEX DIFFERENCES IN ENHANCING VASORELAXATION RESPONSE BY PERIVASCU-LAR ADIPOSE TISSUE IN METABOLIC SYNDROME RATS

Abstract

Objective: Regulation of arterial tone by perivascular adipose tissue (PVAT) differs with sex. We have demonstrated that PVAT compensates vascular tone when vascular dysfunc-tion occurs in mesenteric arteries of male SHRSP. Z-Leprfa/IzmDmcr (SPZF) rats, but such compensation function disappears in the late stage of metabolic syndrome (MetS). In con-trast, the favorable effects of PVAT remain in female SPZF even after the effects disappear in age-matched males. Design and method: Therefore, in this study, we investigated whether the sex differences in PVAT response are observed in another arterial sites in SPZF and in another MetS model, SHR/NDmcr-cp (CP) rats as well. Renal arteries were isolated from male and female SPZF rats and CP rats at 23 weeks of age. Ring preparations with and without PVAT were made. Vasodilation and mRNA transcript levels in PVAT were examined using organ bath methods and quantitative real-time PCR, respectively. Results, and Conclusions: In renal arteries without PVAT of SPZF and CP rats, acetylcholine-induced relaxations were smaller in female than in male. The presence of PVAT increased the relaxations in CP rats only. In contrast, sodium nitroprusside-induced relaxations, nevertheless presence or ab-sence of PVAT, were smaller in female than in male in SPZF rats, but sex differences were not observed in CP rats. Apelin mRNA levels in female CP rats were the highest among groups. The enhancements of acetylcholine-induced relaxations by PVAT were positively correlated with apelin mRNA levels in PVAT. These results demonstrated that sex difference in enhancing vasorelaxation response by PVAT in renal arteries differs to that in mesenteric arteries in SPZF rats at the same age and to that in another MetS model strain, CP rats, at the same age and arterial sites. This discrepancy observed in female rats between two MetS strains may be associated with the difference in arterial dysfunction mechanism; namely, impairment of only endothelial nitric oxide production in CP rats, and deterioration of re-sponse to nitric oxide in smooth muscle in SPZF rats. Furthermore, apelin levels of PVAT may be involved in the appearance of modulation of PVAT on arterial tone.