Gold Nanoparticle associated to Berberine induces vasorelaxation and cytosolic Ca2+ decrease in rat aorta

Abstract

This study aimed to investigate the effect of berberine (BS) and modified surface of gold nanoparticles thioglycolic acid associated to berberine (AuNPTGA‐BS) on rat aortic vascular smooth muscle cells calcium ions concentration and aorta relaxation. Vascular reactivity was studied in denuded rat aortic rings and efficacy (ME) and potency (pD2) of BS in solution and in AuNPTGA and AuNPTGA‐BS were determined. Concentration‐effect curves for BS were constructed in phenylephrine (PE) pre‐contracted aorta. BS in solution, induced PE‐contraction reversal response with ME: 103.3 ± 4.2%, pD2: 5.47 ± 0.15 (n=6) and in AuNPTGA‐BS (ME: 81.9 ± 12.9%, pD2: 5.49 ± 0.25, n=5). The compound AuNP alone failed to induce rat aortic ring relaxation. The effects of the compounds on the cytosolic calcium ions concentration was measured by the fluorescence intensity decrease percentage (%ΔFI) of the calcium ions sensitive dye FLUO‐4AM by laser scanning confocal microscope. We have observed that the addition of BS decreased the fluorescence of the dye with (ΔIF: 39.5 ±5.4% (n=3) and for AuNPTGA‐BS (ΔIF= 65.0±4.7% n=3). On the other hand, AuNPTGA alone had no effect on the fluorescence emission. In conclusion, the vasorelaxation induced by BS and AuNPTGA‐BS is due to the cytosolic calcium ions concentration decrease. Supported by FAPDF, FAPESP, CAPES, CNPq, FINATEC and DPP‐UnB.