Tongxinluo improves cognition by decreasing β-amyloid in spontaneous hypertensive rats

Electroacupuncture and manual acupuncture at LR3 and ST36 have attenuating effects on hypertension and subsequent cognitive dysfunction in spontaneously hypertensive rats: A preliminary resting-state functional magnetic resonance imaging study

Introduction

Chronic hypertension may have a contributory role toward cognitive impairment. Acupuncture exerts protective effects on cognitive functions while controlling the blood pressure. However, the neural mechanism underlying the dual attenuating effect of acupuncture remains unclear. In this study, we investigated the effects of electroacupuncture (EA) and manual acupuncture (MA) on the functional activity of the brain regions of spontaneously hypertensive rats (SHRs) by through resting-state functional magnetic resonance imaging (rs-fMRI). We also evaluated the differences in these functional activities between the EA and MA groups.

Methods

We randomly assigned 30 SHRs into the EA, MA, and model (SHR) groups. Wistar Kyoto rats (n = 10) were used as normal control (WKY). The interventions were administered once every alternate day for 12 weeks. The systolic blood pressure of all rats was recorded every 2 weeks until the end of the intervention. After the intervention, rs-fMRI scanning was performed to access the whole brain data of rats randomly selected from each group evenly. The amplitude of low frequency fluctuation (ALFF) analysis, regional homogeneity (ReHo) analysis, and functional connectivity (FC) analysis were also conducted. The Morris water maze (MWM) test was conducted to evaluate the learning and memory of the rats. Hematoxylin-eosin staining and Nissl staining were performed to observe histopathological changes in the key brain regions.

Results

We demonstrated that, when compared with the SHR group, the EA and MA groups had significantly lower blood pressure and better performance for behavioral test indices, and that the effect of EA was better than that of MA. ALFF and ReHo analyses revealed enhancement of the neuronal activity of some functionally impaired brain areas in the EA and MA groups. The main callback brain regions included the hypothalamus, entorhinal cortex, brain stem, prelimbic cortex, cingulate cortex, corpus callosum, and cerebellum. The FC analysis demonstrated that EA and MA enhanced the functional connectivity between the seeds and brain regions such as the brain stem, entorhinal cortex, hippocampus, prelimbic cortex, and cerebellum. The pathological test of the entorhinal cortex also verified the protective effect of acupuncture on the neuronal functional activity.

Discussion

Our findings suggested that EA and MA exhibited attenuating effects on hypertension and cognitive dysfunction by enhancing the functional activities in the corresponding brain regions. Moreover, EA activated more callback brain regions and functional connectivity than MA, which may explain why the effect of EA was better than that of MA.

Traditional Chinese Medicine Intervenes in Vascular Dementia: Traditional Medicine Brings New Expectations

Vascular dementia (VD) is one of the most common forms of dementia, referring to a group of symptoms that mainly manifest as advanced neurocognitive dysfunction induced by cerebrovascular disease (CVD). A significant number of studies have shown that traditional Chinese medicine (TCM) has a clinical impact on VD and thus has promising prospects. There have been many discussions regarding the pharmacological mechanisms involved in treatment of the kidney, elimination of turbidity, and promotion of blood circulation. TCM has a prominent effect on improving patients’ cognitive function and quality of life. In this review, we summarize the pathogenesis of VD in modern medicine and TCM, traditional prescriptions, single-agent effective ingredients and their pharmacological mechanisms for treating VD, highlight TCM’s characteristics, and discuss TCM’s multi-targeted mechanism for the treatment of VD.

Icariin modulates eNOS activity via effect on post-translational protein-protein interactions to improve erectile function of spontaneously hypertensive rats

BACKGROUND

Type 5 phosphodiesterase inhibitor (PDE5I) has become the first-line treatment for erectile dysfunction (ED). However, its effective rate for hypertension ED is only 60%-70%. How to improve the efficacy of ED treatment is the focus of current research.

OBJECTIVE

To explore whether icariin can improve the erectile function of spontaneously hypertensive rats (SHR) by affecting post-translational protein-protein interactions to regulate endothelial nitric oxide synthetase (eNOS) activity.

METHOD

Twelve-week-old healthy male SHR rats and Wistar-Kyoto rats (WKY) were randomly divided into four groups: SHR control group, SHR + icariin (10 mg/kg·d gavage) treatment group, WKY control group, and WKY + icariin (10 mg/kg·d gavage) treatment group (n = 5). After 4 weeks, the maximum penile intracavernous pressure/mean arterial pressure (ICPmax/MAP), the expression of heat-shock protein 90 (Hsp90), caveolin-1, calmodulin, p-eNOS, and eNOS in penile cavernous tissue and the content of nitric oxide (NO) and cGMP were measured. The interaction between eNOS and Hsp90, caveolin-1, and calmodulin were detected by immunoprecipitation.

RESULT

The ICPmax/MAP in the SHR + icariin treatment group (0.08 ± 0.01, 0.23 ± 0.07, 0.40 ± 0.05) was significantly higher than the SHR group (0.03 ± 0.01, 0.13 ± 0.03, 0.21 ± 0.02) under 3V and 5V electrical stimulations (P < .05). Compared with the SHR group, the expression of HSP90, calmodulin, P-eNOS, eNOS, and P-eNOS/eNOS in the penile cavernous tissue of rats in the WKY group and the SHR + icariin treatment group were significantly increased (P < .05), and the expression of caveolin-1 was significantly decreased (P < .05). The NO content (2.16 ± 0.22 μmol/g) and cGMP concentration (3.69 ± 0.12 pmol/mg) in the SHR + icariin treatment group were significantly higher than those in the SHR group (1.01 ± 0.14 μmol/g, 2.31 ± 0.22 pmol/mg) (P < .05). Compared with the SHR group, the interaction between eNOS and HSP90 in the cavernosa of the rats in the SHR + icariin treatment group was significantly increased (P < .05), the interaction between eNOS and caveolin-1 was significantly decreased (P < .01), and the interaction between eNOS and calmodulin did not significantly change.

DISCUSSION AND CONCLUSION

Up-regulating the expression of HSP90 and calmodulin and inhibiting caveolin-1 in SHR corpus cavernosum, promoting the interaction between eNOS and HSP90, inhibiting the interaction between eNOS and caveolin-1, increasing p-eNOS/eNOS, may be the mechanism of icariin that improves SHR erectile function.

Inhibition of endothelial nitric oxide synthase reverses the effect of exercise on improving cognitive function in hypertensive rats

Hypertension-induced endothelial dysfunction is associated with β-amyloid (Aβ) deposition, a typical pathology of Alzheimer's disease (AD). Endothelial nitric oxide synthase (eNOS) phosphorylation, impaired by phosphatidylinositol 3-kinase (PI3K)/protein kinase-B(Akt) pathway abnormalities in hypertensive rats, has a critical role in endothelial function. However, it is unknown whether eNOS participates in the hypertension-induced pathology of AD. In this study, we investigated the role of eNOS in Aβ deposition and cognitive function in stroke-prone spontaneously hypertensive (SHRSP) rats. Physical exercise was used as a promoter, and N^ω-nitro L-arginine methyl ester (L-NAME) was used as an inhibitor of eNOS to determine the effects of eNOS on SHRSP rats. Compared with Wistar Kyoto (WKY) rats, the hypertensive challenge caused cognitive impairment, decreased eNOS levels and increased amyloid precursor protein (APP), β-secretase, and Aβ levels in the cortex and hippocampus. Sixteen weeks of exercise lowered blood pressure (BP), promoted eNOS expression, ameliorated Alzheimer's pathology, and improved cognitive function in 29-week-old SHRSP rats. Furthermore, daily treatment with L-NAME reversed the beneficial effects of exercise on SHRSP rats. Exercise also decreased the protein levels of insulin-like growth factor-1 (IGF-1), PI3K, and phospho-Akt (p-Akt, ser473). In addition, long-term exercise increased the expression levels of IGF-1, PI3K, and p-Akt (ser473) in the brains of SHRSP rats. In conclusion, eNOS downregulation contributed to hypertension-induced Alzheimer pathology and cognitive impairment. Long-term exercise initiated in rats at a young age promoted eNOS expression and attenuated vascular-related Alzheimer's pathology via the IGF-1/PI3K/p-Akt pathway in SHRSP rats.