The present study compared high-fat style diet (HFSD)-induced renal nerve-dependent dysregulation of the baroreflex control of renal sympathetic nerve activity (RSNA) in ovary-intact and ovariectomized (OVX) rats. Female rats received a normal diet (ND) or a HFSD for 10 weeks prior to the acute study. The rats were anesthetized; RSNA and heart rate (HR) were measured. Acute bilateral renal denervation was performed, and baroreflex gain curves were constructed from the baroreflex changes in RSNA to vasopressor and vasodepressor drugs. Cardiopulmonary baroreflex control of RSNA was assessed by acute saline volume expansion (VE). Mean blood pressure was elevated in the OVX-HFSD rats compared to the HFSD group reaching significance on week 6 of the experimental study (P < 0.01). Adiposity index and creatinine clearance were significantly greater in all HFSD rats compared to their ND counterparts. Fractional excretion of sodium rose initially in all HFSD rats but was normalized towards the end of the study although absolute sodium excretion remained high. In the acute study, baroreflex gain curve sensitivity (A2) of RSNA was similarly decreased in both the HFSD and OVX-HFSD rats by 88% (P < 0.005) and 94% (P < 0.001) respectively compared to their control counterparts, but was normalized following bilateral renal denervation. VE-reduced RSNA in ND and OVX-ND rats by 55% and 52% (both P < 0.001) respectively, but did not alter RSNA in both HFSD and OVX-HFSD female rats. Following bilateral renal denervation, HFSD and OVX-HFSD rats exhibited 37% (P < 0.01) and 24% (P < 0.01) reduction in RSNA respectively. These findings demonstrate that although obesity-induced impairment of baroreflex control of RSNA occurred similarly in HFSD and OVX-HFSD rats, mean blood pressure was increased only in the ovarian hormones deprived-group suggesting that ovarian hormones could have modulatory role on other mechanisms that regulate blood pressure in female obesity.

Impact statement

Over activation of renal sensory nerve in obesity blunts the normal regulation of renal sympathetic nerve activity. To date, there is no investigation that has been carried out on baroreflex regulation of renal sympathetic nerve activity in obese ovarian hormones deprived rat model, and the effect of renal denervation on the baroreflex regulation of renal sympathetic nerve activity. Thus, we investigated the role of renal innervation on baroreflex regulation of renal sympathetic nerve activity in obese intact and ovariectomized female rats. Our data demonstrated that in obese states, the impaired baroreflex control is indistinguishable between ovarian hormones deprived and non-deprived states. This study will be of substantial interest to researchers working on the impact of diet-induced hypertension in pre- and postmenopausal women. This study provides insight into health risks amongst obese women regardless of their ovarian hormonal status and may be integrated in preventive health strategies.

中文翻译：

---

高脂饮食对完整和去卵巢雌性大鼠肾交感神经活动的压力反射控制失调的比较：高脂饮食对完整和切除卵巢的雌性大鼠的肾脏交感神经活动。

本研究比较了高脂饮食（HFSD）诱导的在完整卵巢和去卵巢（OVX）大鼠中肾交感神经活动（RSNA）的压力反射控制的肾神经依赖性失调。在急性研究之前，雌性大鼠接受正常饮食（ND）或HFSD，持续10周。大鼠被麻醉；测量RSNA和心率（HR）。进行了急性双侧肾脏去神经支配，从RSNA的压力反射变化到升压药和降压药建立了压力反射增益曲线。RSNA的心肺压力反射控制通过急性盐水体积扩张（VE）进行评估。与HFSD组相比，OVX-HFSD大鼠的平均血压升高，在实验研究的第6周达到显着水平（P <0.01）。与ND对应者相比，所有HFSD大鼠的肥胖指数和肌酐清除率均显着更高。钠的分数排泄最初在所有HFSD大鼠中均上升，但在研究结束时归一化，尽管绝对钠排泄仍然很高。在急性研究中，HFSD和OVX-HFSD大鼠的RSNA的压力反射反射曲线敏感性（A2）分别较对照组降低了88％（P <0.005）和94％（P <0.001），但在双侧肾神经支配后恢复正常。VE将ND和OVX-ND大鼠的RSNA分别降低了55％和52％（均P <0.001），但在HFSD和OVX-HFSD雌性大鼠中均未改变RSNA。在双侧肾脏去神经后，HFSD和OVX-HFSD大鼠的RSNA分别降低了37％（P <0.01）和24％（P <0.01）。

影响陈述

肥胖中肾感觉神经过度激活会削弱肾交感神经活动的正常调节。迄今为止，尚未进行关于肥胖的卵巢激素剥夺的大鼠模型中肾交感神经活动的压力反射调节的研究，以及肾神经支配对肾交感神经活动的压力反射调节的影响。因此，我们调查了在未受损和去卵巢的雌性大鼠中，肾神经支配对肾交感神经活动的压力反射调节的作用。我们的数据表明，在肥胖状态下，剥夺性卵巢激素与未剥夺性卵巢激素之间的压力反射控制受损是无法区分的。这项研究将对从事绝经前和绝经后妇女饮食引起的高血压影响的研究人员具有重大意义。