engleski

Vascular responses of middle cerebral arteries to flow-induced dilation of ovariectomized Sprague- Dawley rats

Objective: The aim of the present study was to of determine the effect of diabetes mellitus (DM) on flow-induced dilation in ovariectomized healthy and diabetic Sprague-Dawley (SD) rats. Materials and methods: 10 female, ovariectomized SD rats were organized in following groups: a) healthy control group (N=5) and b) experimental group of DM rats (N=5). DM was induced by streptozocin 60mg/kg i.p. at age of 6 weeks. Prior to decapitation, rats were anesthetized with 75 mg/kg ketamine+2.5 mg/kg midazolam. Rat middle cerebral arteries were cannulated for vascular reactivity measurements in response to stepwise increasing pressure (Δ10-Δ100), in the absence/presence of the NOS inhibitor L-NAME or COX-1, 2 inhibitor indomethacin (INDO). To test differences among groups Two-way ANOVA was used, p<0.05 considered significant. Results: DM-OVX rats had significantly reduced flow- induced relaxation (FID) compared to OVX- control group (P<0.01 at Δ100). L-NAME and INDO tended to decrease FID in OVX-control group of rats, but without statistical significance, while in DM-OVX group L-NAME (Δ40-Δ100) and INDO (Δ10- Δ100) provoked vasoconstriction but without statistical significance when compared to baseline. Conclusion: These results demonstrate that: 1) FID of middle cerebral arteries is impaired in DM-OVX rats and 2) NO and metabolites of COX-1, 2 may mediate FID in both groups of rats.

oestrogen; vascular function; flow-mediated dilation

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