engleski

The role of epoxyeicosatrienoic acids in diabetes mellitus-induced impaired vascular relaxation of aortic rings in ovariectomized Sprague-Dawley rats

Aim: The present study was aimed to determine if type 1 diabetes mellitus (DM) affects vascular function, and to elucidate the mechanisms mediating vasorelaxation in both non-ovariectomized and ovariectomized Sprague- Dawley (SD) rats. Materials and Methods: Eighty female SD rats were divided into four groups: non- ovariectomized healthy (non-OVX-CTR) and diabetic (non-OVX-DM), and ovariectomized healthy (OVX-CTR) and diabetic (OVX-DM). Bilateral ovariectomy was performed at the age of 5 weeks, and type 1 DM was induced by streptozotocin at the age of 6 weeks. At the age of 12 weeks, acetylcholine-induced relaxation (AChIR) was assessed in aortic rings in the absence/presence of L-NAME, Indomethacin and MS-PPOH. Aortic tissue mRNA expression of eNOS, iNOS, COX-1, COX-2, thromboxane synthase 1 (TBXAS1), CYP4A1, CYP4A3 and CYP2J3, as well as plasma oxidative stress were measured. Results: AChIR did not differ in non-OVX-DM rats compared to non-OVX-CTR ones. AChIR was significantly reduced in the OVX-DM group compared to the OVX-CTR group. MS-PPOH did not reduce AChIR in OVX-DM rats as it did in OVX- CTR ones. CYP4a3 mRNA expression in OVX-DM rats was significantly lower compared to the OVX-CTR group. Conclusions: Female sex hormones may protect vasorelaxation in type 1 diabetic rats. Type 1 diabetes impairs vasorelaxation to ACh in ovariectomized rats (but not in non- ovariectomized rats) by affecting vasorelaxation pathways mediated by EETs.

diabetes mellitus ; vascular function ; aorta ; epoxyeicosatrienoic acids ; ovariectomy

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