Electroacupuncture attenuates vascular hyporeactivity in a rat model of portal hypertension induced by bile duct ligation

Background: A hyperdynamic circulation and impaired vascular responsiveness to vasoconstrictors are observed in portal hypertension (PHT) rats. Inflammation is a major contributor to the hyperdynamic circulation state in murine models of PHT. Electroacupuncture (EA) may ameliorate the inflammatory response and limit arterial vasodilatation and portal pressure. This study investigated the possible mechanisms underlying putative hemodynamics effects of EA in normal and PHT rats. Methods: PHT was induced by bile duct ligation (BDL) surgery over 4 weeks in rats. Sham-operated and BDL rats were treated with low-frequency EA (2 Hz) at ST36 10 min three times weekly for one or two consecutive weeks (for a total of 3 or 7 treatments, respectively). Serum tumor necrosis factor-α (TNF-α), nitrite/nitrate (NOx) and 6-keto-prostaglandin F1α (6-keto-PGF1α) were analyzed, and hemodynamic variation and contractile responses to phorbol-12,13-dibutyrate and phenylephrine in aortic and superior mesenteric arterial rings were recorded. Inducible (i) and endothelial (3) nitric oxide synthase (NOS), cyclooxygenase-1 (COX-1), and protein kinase C-α (PKC-α) levels were determined by Western blotting. Results: EA significantly reduced portal pressure and serum TNF-α, NOx and 6-keto-PGF1α levels compared to the untreated BDL group, enhanced maximum contractile responses in the aorta, up-regulated PKC-α, and down-regulated iNOS and COX-1 levels. In addition, EA decreased the aortic angiogenesis signaling cascade, reflected by down-regulation of vascular endothelial growth factor (VEGF) abundance and transforming growth factor β receptor (TGFβR)I/II expression, as assessed by immunostaining. Conclusion: EA attenuates TNF-α, NO and 6-keto-PGF1α overproduction, modulates the vascular levels of constitutive NOS and PKC-α, blunts the development of the angiogenesis cascade, and enhances vascular contractile force in PHT rats.

Abstract P267: Arbidol, A Targeted Covid-19 Therapy, Inhibited Contractile Responses To Phenylephrine In Mesenteric Arteries And Aortas Of Hypertensive Rats

Background: Hypertension is the most prevalent comorbidity of COVID-19 infection. This infection is caused by the severe acute respiratory syndrome coronavirus SARS-CoV-2. SARS-CoV-2 is a single-stranded RNA and could activate the endosomal Toll-like receptor 7 (TLR7), indicating a vital role of the receptor in its therapeutic target. Studies have reported that the lysosomotropic drug chloroquine has antihypertensive effects through its action on inhibiting the endosomal TLRs. Arbidol is a potential broad-spectrum antiviral used in the treatment of many viral infections including influenza. Arbidol prevents viral infection by interacting with aromatic acids; arbidol also binds to lipid membranes, altering the configuration of the cytoplasm or endosome. Wang et al., in 2020 reported that arbidol effectively inhibited the coronavirus SARS-CoV-2 in vitro by impeding viral attachment and release from the endolysosomes. Hypothesis: We hypothesized that arbidol would improve vascular reactivity in hypertension. Methods: We studied the effects of arbidol on the contractility of mesenteric resistance arteries (MRA) and aortas of male Wistar rats (20 weeks old, n=4) and spontaneously hypertensive rats (SHR) (20 weeks old, n=4) on a myograph by incubating the arterial rings with 10μM arbidol (Sigma, USA.) or vehicle (DMSO) for 30 mins. Statistical analysis was performed using nonlinear regression, and one- and two-way ANOVAs. Results: Arbidol (10 μM) impaired the contractile responses of MRA and aorta from normotensive and hypertensive rats to phenylephrine (PE). MRA Wistar: (pEC50 6.11 ± 0.15 vs 3.42 ± 0.38), SHR: (5.89 ± 0.19 vs 3.56 ± 0.19) and aorta Wistar: (pEC 50 7.49 ± 0.19 vs 5.97 ± 0.14), SHR (pEC50 7.14 ± 0.31 vs 4.41 ± 0.15). The arbidol-induced impaired contraction to PE was greater in the SHR aorta compared with the Wistar aorta. After washing out the drug, the arterial rings contracted to 120mM KCl at the same magnitude as the initial contraction to 120mM KCl. Conclusions: Our data demonstrate that arbidol impairs vascular contractile responses to α-adrenergic stimulation, with a greater response in the hypertensive rats. This indicates antihypertensive effects potentially through the regulation of TLR signaling.

Cross-organ sensitization between the prostate and bladder in an experimental rat model of lipopolysaccharide (LPS)-induced chronic pelvic pain syndrome

Background The aim of the current study was to investigate the effects of chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) on bladder function via prostate-to-bladder cross-sensitization in a rat model of lipopolysaccharide (LPS)-induced prostate inflammation. Methods Male rats were intraprostatically injected with LPS or saline, serving as control. Micturition parameters were examined in a metabolic cage 10 or 14 days later. Subsequently, to evaluate bladder function, cystometry was performed. Micturition cycles were induced by saline infusion and cholinergic and purinergic contractile responses were measured by intravenous injection with methacholine and ATP, respectively. Thereafter, the prostate and bladder were excised and assessed histopathologically for possible inflammatory changes. Results Metabolic cage experiments showed increased urinary frequency in rats with LPS-induced CP/CPPS. Cystometry showed a significant increase in the number of non-voiding contractions, longer voiding time and lower compliance in CP/CPPS animals compared to controls. Induction of CP/CPPS led to significantly reduced cholinergic and purinergic bladder contractile responses. Histopathological analysis demonstrated prostatic inflammation in CP/CPPS animals. There were no significant differences between the groups regarding the extent or the grade of bladder inflammation. Prostate weight was not significantly different between the groups. Conclusions The present study shows that prostate-to-bladder cross-sensitization can be triggered by an infectious focus in the prostate, giving rise to bladder overactivity and alterations in both afferent and efferent signalling. Future studies are required to fully understand the underlying mechanisms.

Pericyte Contractile Responses to Endothelin-1 and Aβ Peptides: Assessment by Electrical Impedance Assay

Pericytes are vascular mural cells that contract and relax in response to vasoactive stimuli to regulate neurovascular coupling and cerebral blood flow. Pericytes are damaged and degenerate in Alzheimer’s disease (AD). We previously showed that the level of the regulatory vasoconstrictor, endothelin-1 (EDN1), is elevated in AD cerebral cortex and upregulated by amyloid-beta (Aβ). We have used electrical impedance analysis to monitor the contractile and proliferative response of cultured human fetal and adult brain-derived pericytes to EDN1 in real-time. EDN1 caused transient, dose-dependent contraction of fetal and adult brain pericytes that was mediated by EDN1 type A receptors and increased the subsequent proliferation of fetal but not adult cells. The contractile responses to EDN1 were weaker in the adult pericytes. The EDN1-mediated contractile response of fetal pericytes was unchanged after exposure to Aβ1–40 or Aβ1–42 (0.1–10 μM) for 1 h but both contraction and subsequent relaxation were significantly impaired upon exposure to Aβ for 24 h. These data suggest that chronic exposure to Aβ interferes with EDN1-mediated pericyte contractility, potentially contributing to neurovascular uncoupling and reduced cerebral blood flow in AD.

Potentiation of Acetylcholine-Induced Relaxation of Aorta in Male UC Davis Type 2 Diabetes Mellitus (UCD-T2DM) Rats: Sex-Specific Responses

Previous reports suggest that diabetes may differentially affect the vascular beds of females and males. The objectives of this study were to examine whether there were (1) sex differences in aortic function and (2) alterations in the relative contribution of endothelium-derived relaxing factors in modulating aortic reactivity in UC Davis Type 2 Diabetes Mellitus (UCD-T2DM) rats. Endothelium-dependent vasorelaxation (EDV) in response to acetylcholine (ACh) was measured in aortic rings before and after exposure to pharmacological inhibitors. Relaxation responses to sodium nitroprusside were assessed in endothelium-denuded rings. Moreover, contractile responses to phenylephrine (PE) were measured before and after incubation of aortic rings with a nitric oxide synthase (NOS) inhibitor in the presence of indomethacin. Metabolic parameters and expression of molecules associated with vascular and insulin signaling as well as reactive oxygen species generation were determined. Diabetes slightly but significantly impaired EDV in response to ACh in aortas from females but potentiated the relaxation response in males. The potentiation of EDV in diabetic male aortas was accompanied by a traces of nitric oxide (NO)- and prostanoid-independent relaxation and elevated aortic expression of small- and intermediate conductance Ca2+-activated K+ channels in this group. The smooth muscle sensitivity to NO was not altered, whereas the responsiveness to PE was significantly enhanced in aortas of diabetic groups in both sexes. Endothelium-derived NO during smooth muscle contraction, as assessed by the potentiation of the response to PE after NOS inhibition, was reduced in aortas of diabetic rats regardless of sex. Accordingly, decreases in pAkt and peNOS were observed in aortas from diabetic rats in both sexes compared with controls. Our data suggest that a decrease in insulin sensitivity via pAkt-peNOS-dependent signaling and an increase in oxidative stress may contribute to the elevated contractile responses observed in diabetic aortas in both sexes. This study demonstrates that aortic function in UCD-T2DM rats is altered in both sexes. Here, we provide the first evidence of sexual dimorphism in aortic relaxation in UCD-T2DM rats.

Mechanisms in Tridax procumbens leaf extract reversal of paroxetine-induced erectile dysfunction in corpus cavernosum of male Wistar rats

Introduction: Aqueous leave extract of Tridax procumbens (AETPL) is reported to improve erectile functions; however, the mechanism is unclear. This study investigates the mechanism involved in the contractile activity of the corpus cavernosum after AETPL treatment of paroxetine-induced erectile dysfunctional adult male Wistar rats. Methods: A total of 20 male Wistar rats were categorized into four groups of five and treated orally for four weeks: Group 1 (distilled water), Group 2 (paroxetine 10 mg/kg), Group 3 (paroxetine + AETPL 100 mg/kg), and Group 4 (paroxetine + Viagra 0.5 mg/kg). Contractile responses of excised corpus cavernosum strips (CS) were determined in response to acetylcholine (ACh), phenylephrine (PHE), potassium chloride (KCl), and calcium chloride (CaCl2), and after incubation in L-NAME, indomethacin, nifedipine, adenosine, caffeine, nicorandil, and acetovanillone. Results: The relaxation response (%) of CS to ACh was significantly inhibited in the paroxetine group compared to the AETPL- and the Viagra-co-treated group. Pre-incubation in L-NAME considerably enhanced the percentage relaxation in groups co-treated with AETPL and Viagra. Groups co-treated with AETPL and Viagra significantly inhibited contraction in response to cumulative doses of CaCl2. Contractile responses of CS to cumulative doses of PHE after incubation in caffeine and adenosine were considerably inhibited in groups co-treated with AETPL and Viagra. Similarly, nicorandil (10-4 M) enhanced the percentage relaxation to cumulative doses of ACh (10-9 — 10-5 M) in groups co-treated with AETPL and Viagra. The pre-incubation of CS with acetovanillone (10-4 M) enhanced the percentage relaxation to ACh across groups. Conclusion: Erectile dysfunction was reversed by AETPL-induced antioxidant/NADPH oxidase inhibitor activity, reduced calcium sensitivity, activation of ATP-sensitive K+ channel, and endothelial Nitric Oxide (NO) release.

Uterine contractile activity and fetal outcome in rats treated with vitamin C during late gestational variable stress exposure

Objectives Stress responses vary throughout pregnancy and impact of late gestational variable stress (LGVS) with vitamin C supplementation on uterine contractility is barely explored. This study investigates fetal weight outcome and in-vitro uterine contractile responses to pharmacological agents during LGVS exposure. Methods Twenty four nulliparous pregnant rats were divided into four groups of six. During gestation days 10–19, groups 1 & 2 received normal saline and vitamin C (10 mg/kg) respectively. Groups 3 and 4 were exposed to stress (sleep deprivation, predator exposure, immobility, rapid cage changes, noise, and foreign object) with group 4 concurrently supplemented with vitamin C (10 mg/kg). Serum cortisol, oxidative bio-markers, fetal weights and in-vitro contractile responses of excised uterine tissue to acetylcholine (Ach), oxytocin, calcium chloride (CaCl2), potassium chloride (KCl), diclofenac, and magnesium ions were determined. Results Malondialdehyde activity and cortisol were significantly increased in variable stress only exposed group when compared with control and vitamin C supplemented groups. Fetal body weights, superoxide dismutase and catalase activity were significantly reduced in variable stress only exposed group. Significantly impaired contractile responses to Ach, CaCl2 & KCl in variable stress only exposed group were modulated in vitamin C supplemented groups. Impaired contractile response to oxytocin was however not reversed. Relaxation responses to diclofenac and magnesium ions were statistically unaltered across groups. Conclusions Impaired fetal weights and uterine contractile activity to Ach, CaCl2 and KCl during LGVS was modulated by vitamin C supplementation. Impaired oxytocin contractile activity was however unreversed.