MK571 通过抑制多药耐药蛋白增加 cGMP 积累从而恢复肥胖小鼠的勃起功能。

Inhibition of multidrug resistance proteins by MK571 restored the erectile function in obese mice through cGMP accumulation.

机构信息

Department of Translation Medicine (Pharmacology area), Faculty of Medical Sciences, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil.

出版信息

Andrology. 2023 Mar;11(3):611-620. doi: 10.1111/andr.13340. Epub 2022 Nov 25.

DOI:10.1111/andr.13340

PMID:36375168

Abstract

BACKGROUND

Intracellular levels of cyclic nucleotides can also be controlled by the action of multidrug resistance protein types 4 (MRP4) and 5 (MRP5). To date, no studies evaluated the role of their inhibition in an animal model of erectile dysfunction (ED).

OBJECTIVES

To evaluate the effect of a 2-week treatment with MK571, an inhibitor of the efflux of cyclic nucleotides in the ED of obese mice.

MATERIALS AND METHODS

Mice were divided in three groups: (i) lean, (ii) obese, and (iii) obese + MK571. The corpus cavernosum (CC) were isolated, and concentration-response curves to acetylcholine (ACh), sodium nitroprusside (SNP), and tadalafil in addition to electrical field stimulation (EFS) were carried out in phenylephrine pre-contracted tissues. Expression of ABCC4 and ABCC5, intracellular levels of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP), the protein levels for pVASP and pVASP , and the intracavernous pressure (ICP) were also determined. The intracellular and extracellular (supernatant) ratios in CC from obese and lean stimulated with a cGMP-increasing substance (BAY 58-2667) in the absence and presence of MK571 (20 μM, 30 min) were also assessed.

RESULTS

The treatment with MK571 completely reversed the lower relaxing responses induced by EFS, ACh, SNP, and tadalafil observed in obese mice CC in comparison with untreated obese mice. Cyclic GMP and p-VASP expression were significantly reduced in CC from obese groups. MK571 promoted a sixfold increase in cGMP without interfering in the protein expression of p-VASP . Neither the cAMP levels nor p-VASP were altered in MK571-treated animals. The ICP was ∼50% lower in obese than in the lean mice; however, the treatment with MK571 fully reversed this response. Expressions of ABCC4 and ABCC5 were not different between groups. The intra/extracellular ratio of cGMP was similar in CC from obese and lean mice stimulated with BAY 58-2667.

CONCLUSIONS

The MRPs inhibition by MK571 favored the accumulation of cGMP in the smooth muscle cells, thus improving the smooth muscle relaxation and the erectile function in obese mice.

摘要

背景

细胞内环核苷酸的水平也可以通过多药耐药蛋白 4（MRP4）和 5（MRP5）的作用来控制。迄今为止，尚无研究评估其抑制剂在勃起功能障碍（ED）动物模型中的作用。

目的

评估 2 周 MK571 治疗对肥胖小鼠 ED 的影响，MK571 是一种抑制环核苷酸外排的抑制剂。

材料和方法

将小鼠分为三组：（i）瘦鼠，（ii）肥胖鼠，和（iii）肥胖+MK571 组。分离海绵体（CC），在预先收缩的组织中进行乙酰胆碱（ACh）、硝普钠（SNP）和他达拉非的浓度-反应曲线以及电刺激（EFS）。还测定了 ABCC4 和 ABCC5 的表达、环腺苷酸单磷酸（cAMP）和环鸟苷酸单磷酸（cGMP）的细胞内水平、pVASP 和 pVASP 的蛋白水平以及海绵体内压（ICP）。还评估了在不存在和存在 MK571（20 μM，30 分钟）的情况下，用增加 cGMP 的物质（BAY 58-2667）刺激的 CC 中的细胞内和细胞外（上清液）比率。

结果

与未经治疗的肥胖小鼠相比，MK571 治疗完全逆转了肥胖小鼠 CC 中由 EFS、ACh、SNP 和他达拉非诱导的较低的松弛反应。CC 中的 cGMP 和 p-VASP 表达显著降低。MK571 促进 cGMP 增加六倍，而不干扰 p-VASP 的蛋白表达。MK571 治疗动物的 cAMP 水平或 p-VASP 均未改变。肥胖小鼠的 ICP 比瘦小鼠低约 50%；然而，MK571 的治疗完全逆转了这种反应。ABCC4 和 ABCC5 的表达在肥胖组和瘦鼠组之间没有差异。用 BAY 58-2667 刺激的肥胖和瘦小鼠的 CC 中的 cGMP 细胞内外比值相似。