Inhibitor Indomethacin Research Articles

Tanacetum parthenium and parthenolide increase defensive agents and promote antisecretory activity supporting their gastroprotective actions in rodents

Tanacetum parthenium is popularly used to treat gastric disorders. However, the gastroprotective activity has not yet been tested. This study evaluated the anti-ulcer gastric effects of hydroalcoholic extract from T. parthenium (HETp) and parthenolide (PTL), its bioactive compound. Our findings revealed a significant reduction in HETp (10, 30, or 100 mg/Kg) and PTL (5 and 50 mg/Kg) in ethanol and piroxicam-induced ulcers, and this evidence was corroborated histologically. In addition, we explored the acid antisecretory activity by the pylorus ligation. Moreover, in mice pre-treated with the inhibitors indomethacin, L-NAME, and yohimbine, the antiulcerogenic effects of HETp and PTL were abolished, suggesting the involvement of nitric oxide, adrenergic receptors and prostaglandins in gastroprotective effects. Additionally, HETp and PTL prevented the depletion of SOD and CAT and decreased the activity of MPO and the levels of GSH and LPO. The results suggest that gastroprotection of HETp and PTL involves different pharmacological pathways.

Di(2-ethylhexyl) phthalate exposure aggravates hypoxia/reoxygenation injury in cerebral endothelial cells by downregulating epithelial cadherin expression.

Di-(2-ethylhexyl) phthalate (DEHP) is a widely used plasticizer that has adverse health effects. Most phthalates exhibit reproductive toxicity and are associated with diseases such as cardiovascular disorders. However, the effect of DEHP exposure on acute hypoxia/reperfusion injury remains unknown. Therefore, we assessed whether hypoxia/reperfusion injury is aggravated by exposure to DEHP and investigated plausible underlying mechanisms, including oxidative stress and expression of cyclooxygenase-2 (COX-2)/prostaglandin E2 (PGE2) and endothelial junctional proteins. bEnd.3 cells were exposed to DEHP and subsequently subjected to oxygen-glucose deprivation (OGD). Cell viability was analyzed using 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) proliferation assay. The effect of DEHP/OGD/reoxygenation (R) was evaluated by assessing the levels of NO, reactive oxygen species (ROS), and PGE2. The expression of COX-2, cleaved caspase-3, cleaved PARP, inducible nitric oxide synthase (iNOS), and the endothelial tight junction proteins claudin-5 and ZO-1 was evaluated using quantitative polymerase chain reaction and western blotting. OGD/R decreased cell viability, and DEHP exposure before OGD/R further aggravated cell viability. DEHP/OGD/R significantly increased NO, PGE2, and ROS production following OGD/R. In the DEHP/OGD/R group, iNOS, COX-2, cleaved caspase-3, and cleaved PARP expression increased, and claudin-5 and ZO-1 levels decreased compared with those in the OGD/R group. E-Cadherin expression decreased significantly after DEHP/OGD/R exposure compared with that after OGD/R; this decrease in expression was recovered by treatment with the COX-2 inhibitor indomethacin and antioxidant N-acetylcysteine. Exposure to DEHP exacerbated hypoxia-reoxygenation injury. The enhanced damage upon DEHP exposure was associated with increased oxidative stress and COX-2 expression, leading to E-cadherin downregulation and increased apoptosis.

Effect of central administration of indomethacin on anandamide-induced GnRH/LH secretion in the hypothalamus of anoestrous ewes.

It is suggested that cannabinoids (CBs) may disturb reproduction through action on hypothalamic gonadotropin-releasing hormone (GnRH) neurons directly or indirectly through intermediates such as prostaglandins. The study aimed to determine the influence of intracerebroventricular (i.c.v.) injection of the endogenous cannabinoid anandamide (N-arachidonoylethanolamine - AEA), alone or with the prostaglandin synthesis inhibitor indomethacin (IND), on GnRH/luteinising hormone (LH) secretion. The purpose of the research was to clarify the role of endocannabinoids and their interaction with prostaglandins in the regulation of reproduction at the level of the hypothalamus and pituitary in anoestrous sheep. The study was performed on 24 anoestrous ewes divided into four experimental groups: a control group receiving i.c.v. injection of Ringer-Locke solution, an AEA group that received i.c.v. injection of 30 μM of AEA, an IND group receiving i.c.v. injection of 5 μM of IND and an AEA + IND group that received i.c.v. injections of 30 μM of AEA and 5 μM of IND. Anandamide stimulated GnRH protein and gene expression in the median eminence and protein expression in the preoptic area without influencing GnRH messenger RNA (mRNA) in this structure. Indomethacin reversed the changes in GnRH secretion after AEA administration. It was also found that AEA stimulated LH mRNA in the pituitary without influencing LH release. Our results support the role of endogenous cannabinoids in the regulation of reproductive processes at the central nervous system level. They may act directly on the hypothalamic GnRH neurons or indirectly through intermediates such as prostaglandins.

Urothelium-derived prostanoids enhance contractility of urinary bladder smooth muscle and stimulate bladder afferent nerve activity in the mouse.

The transitional epithelial cells (urothelium) that line the lumen of the urinary bladder form a barrier between potentially harmful pathogens, toxins, and other bladder contents and the inner layers of the bladder wall. The urothelium, however, is not simply a passive barrier, as it can produce signaling factors, such as ATP, nitric oxide, prostaglandins, and other prostanoids, that can modulate bladder function. We investigated whether substances produced by the urothelium could directly modulate the contractility of the underlying urinary bladder smooth muscle. Force was measured in isolated strips of mouse urinary bladder with the urothelium intact or denuded. Bladder strips developed spontaneous tone and phasic contractions. In urothelium-intact strips, basal tone, as well as the frequency and amplitude of phasic contractions, were 25%, 32%, and 338% higher than in urothelium-denuded strips, respectively. Basal tone and phasic contractility in urothelium-intact bladder strips were abolished by the cyclooxygenase (COX) inhibitor indomethacin (10 µM) or the voltage-dependent Ca2+ channel blocker diltiazem (50 µM), whereas blocking neuronal sodium channels with tetrodotoxin (1 µM) had no effect. These results suggest that prostanoids produced in the urothelium enhance smooth muscle tone and phasic contractions by activating voltage-dependent Ca2+ channels in the underlying bladder smooth muscle. We went on to demonstrate that blocking COX inhibits the generation of transient pressure events in isolated pressurized bladders and greatly attenuates the afferent nerve activity during bladder filling, suggesting that urothelial prostanoids may also play a role in sensory nerve signaling.NEW & NOTEWORTHY This paper provides evidence for the role of urothelial-derived prostanoids in maintaining tone in the urinary bladder during bladder filling, not only underscoring the role of the urothelium as more than a barrier but also contributing to active regulation of the urinary bladder. Furthermore, cyclooxygenase products greatly augment sensory nerve activity generated by bladder afferents during bladder filling and thus may play a role in perception of bladder fullness.

The Vasodilator Effect and Mechanism of 18β-glycyrrhetinic Acid on Isolated Pulmonary Artery Rings in Rats

Background: The purpose of this study was to evaluate the effect of 18β-glycyrrhetinic acid (18β-GA) on isolated rat pulmonary artery vascular rings as well as the mechanism that lies behind the diastolic effects of this compound. Methods: To examine the effects of various doses of 18β-GA on resting normal vascular rings, we used isolated rat pulmonary artery vascular rings. The isolated rat pulmonary artery vascular ring was precontracted with phenylephrine (PE) and potassium chloride solution (KCl), which allowed for the observation of the diastolic effects of 18β-GA, as well as the effects of various concentrations of 18β-GA on blocking the four potassium channels of glibenclamide, barium chloride (BaCl2), tetraethylamine (TEA), or 4-aminopyridine; the impact of various 18β-GA concentrations on the pulmonary artery vasodilation effect pre-use of the nitric oxide synthase inhibitors l-nitroarginine methyl ester and indomethacin. Results: It was shown that 18β-GA has concentration-dependent diastolic effects on isolated rat pulmonary vascular rings that have been precontracted with PE and KCl but it has no effect on resting isolated thoracic aortic vascular rings. Conclusion: The two Kir and Kv channels may be connected to the endothelium-dependent vasodilation mechanism of 18β-GA.

Extracellular acidification attenuates bronchial contraction via an autocrine activation of EP2 receptor: Its diminishment in murine experimental asthma

PurposeExtracellular acidification is a major component of tissue inflammation, including airway inflammation in asthmatics. However, its physiological/pathophysiological significance in bronchial function is not fully understood. Currently, the functional role of extracellular acidification on bronchial contraction was explored. MethodsLeft main bronchi were isolated from male BALB/c mice. Epithelium-removed tissues were exposed to acidic pH under submaximal contraction induced by 10−5 M acetylcholine in the presence or absence of a COX inhibitor indomethacin (10−6 M). Effects of AH6809 (10−6 M, an EP2 receptor antagonist), BW A868C (10−7 M, a DP receptor antagonist) and CAY10441 (3×10−6 M, an IP receptor antagonist) on the acidification-induced change in tension were determined. The release of prostaglandin E2 (PGE2) from epithelium-denuded tissues in response to acidic pH was assessed using an ELISA. ResultsIn the bronchi stimulated with acetylcholine, change in the extracellular pH from 7.4 to 6.8 caused a transient augmentation of contraction followed by a sustained relaxing response. The latter inhibitory response was abolished by indomethacin and AH6809 but not by BW A868C or CAY10441. Both indomethacin and AH6809 significantly increased potency and efficacy of acetylcholine at pH 6.8. Stimulation with low pH caused an increase in PGE2 release from epithelium-denuded bronchi. Interestingly, the acidic pH-induced bronchial relaxation was significantly reduced in a murine asthma model that had a bronchial hyperresponsiveness to acetylcholine. ConclusionTaken together, extracellular acidification could inhibit the bronchial contraction via autocrine activation of EP2 receptors. The diminished acidic pH-mediated inhibition of bronchial tone may contribute to excessive bronchoconstriction in inflamed airways such as asthma.

Mycobacterium marinum mediates regulation of prostaglandin E2 expression on host immune response through cyclooxygenase pathway.

Investigate the role of COX signaling in activating the PGE2-EP2 pathway. Utilized a marine Mycobacterium infection model in zebrafish. Marine mycobacteria were stained with fluorescein isothiocyanate. The COX inhibitor indomethacin, EP2 receptor inhibitor AH6809, EP4 receptor inhibitor AH23848 and clodronate Liposomes were used to investigate the role of COX, EP2, EP4 and macrophage whether participating in combat marine mycobacterial infection. The expression level of the target gene was detected using real-time fluorescence quantitative PCR instrument. The findings revealed that larvae exposed to the COX inhibitor indomethacin or the EP2 receptor inhibitor AH6809 demonstrated a significantly higher mortality rate due to marine mycobacterium infection than those in the control group. Administration of exogenous prostaglandin E2 (PGE2) rescued the survival of zebrafish infected with marine mycobacteria and treated with indomethacin. Additionally, a significant reduction in survival rate was noted in macrophage-depleted zebrafish infected with marine mycobacteria. The host may combat marine mycobacterium infection via COX signaling, which activates the PGE2-EP2 pathway and mediates macrophage resistance.

An adaptable in silico ensemble model of the arachidonic acid cascade.

Eicosanoids are a family of bioactive lipids, including derivatives of the ubiquitous fatty acid arachidonic acid (AA). The intimate involvement of eicosanoids in inflammation motivates the development of predictive in silico models for a systems-level exploration of disease mechanisms, drug development and replacement of animal models. Using an ensemble modelling strategy, we developed a computational model of the AA cascade. This approach allows the visualisation of plausible and thermodynamically feasible predictions, overcoming the limitations of fixed-parameter modelling. A quality scoring method was developed to quantify the accuracy of ensemble predictions relative to experimental data, measuring the overall uncertainty of the process. Monte Carlo ensemble modelling was used to quantify the prediction confidence levels. Model applicability was demonstrated using mass spectrometry mediator lipidomics to measure eicosanoids produced by HaCaT epidermal keratinocytes and 46BR.1N dermal fibroblasts, treated with stimuli (calcium ionophore A23187), (ultraviolet radiation, adenosine triphosphate) and a cyclooxygenase inhibitor (indomethacin). Experimentation and predictions were in good qualitative agreement, demonstrating the ability of the model to be adapted to cell types exhibiting differences in AA release and enzyme concentration profiles. The quantitative agreement between experimental and predicted outputs could be improved by expanding network topology to include additional reactions. Overall, our approach generated an adaptable, tuneable ensemble model of the AA cascade that can be tailored to represent different cell types and demonstrated that the integration of in silico and in vitro methods can facilitate a greater understanding of complex biological networks such as the AA cascade.

Aldo-keto reductase family member C3 (AKR1C3) promotes hepatocellular carcinoma cell growth by producing prostaglandin F2α.

Hepatocellular carcinoma (HCC) is a leading cause of death worldwide. Current therapies are effective for HCC patients with early disease, but many patients suffer recurrence after surgery and have a poor response to chemotherapy. Therefore, new therapeutic targets are needed. We analyzed gene expression profiles between HCC tissues and normal adjacent tissues from public databases and found that the expression of genes involved in lipid metabolism was significantly different. The analysis showed that AKR1C3 was upregulated in tumors, and high AKR1C3 expression was associated with a poorer prognosis in HCC patients. In vitro, assays demonstrated that the knockdown of AKR1C3 or the addition of the AKR1C3 inhibitor indomethacin suppressed the growth and colony formation of HCC cell lines. Knockdown of AKR1C3 in Huh7 cells reduced tumor growth in vivo. To explore the mechanism, we performed pathway enrichment analysis, and the results linked the expression of AKR1C3 with prostaglandin F2 alpha (PGF2α) downstream target genes. Suppression of AKR1C3 activity reduced the production of PGF2α, and supplementation with PGF2α restored the growth of indomethacin-treated Huh7 cells. Knockdown of the PGF receptor (PTGFR) and treatment with a PTGFR inhibitor significantly reduced HCC growth. We showed that indomethacin potentiated the sensitivity of Huh7 cells to sorafenib. In summary, our results indicate that AKR1C3 upregulation may promote HCC growth by promoting the production of PGF2α, and suppression of PTGFR limited HCC growth. Therefore, targeting the AKR1C3-PGF2α-PTGFR axis may be a new strategy for the treatment of HCC.

COX-2 inhibition mediated aggregation-induced emission photosensitizer target the Golgi apparatus for selective imaging of cancer cells and enhanced photodynamic therapy

Photodynamic therapy (PDT) exerts its therapeutic effects by inducing apoptosis, necrosis, and microvascular damage in tumor cells, but it also causes inflammation and induces the expression of angiogenic factors, accelerating tumor metastasis and proliferation. In this study, aggregation-induced emission (AIE) photosensitizer (PS) for PDT was combined with the cyclooxygenase-2 (COX-2) inhibitor indomethacin (IMC) for cancer-selective imaging and more efficiency in inducing apoptosis in cancer cells. In detail, inhibition of COX-2-mediated AIE PS effectively targeted the Golgi apparatus (GA) of cancer cells to generate large amounts of reactive oxygen species (ROS) in situ, thereby exerting a PDT effect. Specifically, COX-2 and other key enzymes that trigger inflammation and metastasis were significantly inhibited. It had more potent anti-tumor activity (tumor inhibition rate of 64.32 %), as well as anti-metastatic and anti-proliferative effects compared to the use of usual AIE PS.

Investigating the Cardiovascular Benefits of Dapagliflozin: Vasodilatory Effect on Isolated Rat Coronary Arteries

Dapagliflozin, a sodium–glucose co-transporter 2 (SGLT2) inhibitor, is an antidiabetic medication that reduces blood glucose. Although it is well known that dapagliflozin has additional benefits beyond glycemic control, such as reducing blood pressure and lowering the risk of cardiovascular events, no sufficient research data are available on the direct effect of dapagliflozin on cardiovascular function. Thus, in this study, we investigated the direct vascular effect of dapagliflozin on isolated rat coronary arteries. The left descending coronary arteries of 13-week-old male Sprague Dawley rats were cut into segments 2–3 mm long and mounted in a multi-wire myography system to measure isometric tension. Dapagliflozin effectively reduced blood vessel constriction induced by U-46619 (500 nM) in coronary arteries regardless of the endothelium. Treatment with an eNOS inhibitor (L-NNA, 100 μM), sGC inhibitor (ODQ, 5 μM), or COX inhibitor (indomethacin, 3 μM) did not affect the vasodilation induced by dapagliflozin. The application of a Ca2+-activated K+ channel (KCa) blocker (TEA, 2 mM), voltage-dependent K+ channel (KV) blocker (4-AP, 2 mM), ATP-sensitive K+ channel blocker (KATP) glibenclamide (3 μM), and inward-rectifier K+ channel (KIR) blocker (BaCl2, 30 μM) did not affect the dapagliflozin-induced vasodilation either. The treatment with dapagliflozin decreased contractile responses induced by the addition of Ca2+, which suggested that the extracellular Ca2+ influx was inhibited by dapagliflozin. Treatment with dapagliflozin decreased the phosphorylation level of the 20 kDa myosin light chain (MLC20) in vascular smooth muscle cells. In the present study, we found that dapagliflozin has a significant vasodilatory effect on rat coronary arteries. Our findings suggest a novel pharmacologic approach for the treatment of cardiovascular diseases in diabetic patients through the modulation of Ca2+ homeostasis via dapagliflozin administration.

Protective effect of Amauroderma rugosum ethanol extract and its primary bioactive compound, ergosterol, against acute gastric ulcers based on LXR-mediated gastric mucus secretions

BackgroundAmauroderma rugosum (Blume & T. Nees) Torrend (Ganodermataceae) is an edible mushroom with a wide range of medicinal values. Our previous publication demonstrated the therapeutic effects of the water extract of A. rugosum (WEA) against gastric ulcers. However, the protective effects of the ethanol extract of A. rugosum (EEA) on gastric mucosa and its major active constituents have not yet been elucidated. PurposeThis study aims to evaluate the gastroprotective effects and underlying mechanisms of EEA and its fat-soluble constituent, ergosterol, in acute gastric ulcers. Study design and methodSD rats were pre-treated with EEA (50, 100, and 200 mg/kg) or ergosterol (5, 10, and 20 mg/kg), and acute gastric ulcer models were constructed using ethanol, gastric mucus secretion inhibitor (indomethacin) or pyloric-ligation. The gastric ulcer area, histological structure alterations (H&E staining), and mucus secretion (AB-PAS staining) were recorded. Additionally, Q-PCR, western blotting, immunohistochemistry, ELISA, molecular docking, molecular dynamics simulations, MM-GBSA analysis, and surface plasmon resonance assay (SPR) were used to investigate the underlying mechanisms of the gastroprotective effect. ResultCompared with WEA, which primarily exerts its anti-ulcer effects by inhibiting inflammation, EEA containing fat-soluble molecules showed more potent gastroprotective effect through the promotion of gastric mucus secretion, as the anti-ulcer activity was partly blocked by indomethacin. Meanwhile, EEA exhibited anti-inflammatory effects by suppressing the production of IL-6, IL-1β, TNF-α, and NO, thereby inhibiting the MAPK pathway. Significantly, ergosterol (20 mg/kg), the bioactive water-insoluble compound in EEA, exhibited a gastroprotective effect comparable to that of lansoprazole (30 mg/kg). The promotion of gastric mucus secretion contributed to the effects of ergosterol, as indomethacin can completely block it. The upregulations of COX1-PGE2 and C-fos, an activator protein 1 (AP-1) transcription factor, were observed after the ergosterol treatment. Ergosterol acted as an LXRβ agonist via van der Waals binding and stabilizing the LXRβ protein without compromising its flexibility, thereby inducing the upregulation of AP-1 and COX-1. ConclusionEEA and its primary bioactive compound, ergosterol, exert anti-ulcer effects by promoting gastric mucus secretion through the LXRβ/C-fos/COX-1/PGE2 pathway.

Deficiency of long-chain acyl-CoA synthetase 4 leads to lipopolysaccharide-induced mortality in a mouse model of septic shock.

Long-chain acyl-CoA synthetase 4 (ACSL4) converts free highly unsaturated fatty acids (HUFAs) into their acyl-CoA esters and is important for HUFA utilization. HUFA-containing phospholipids produced via ACSL4-dependent reactions are involved in pathophysiological events such as inflammatory responses and ferroptosis as a source for lipid mediators and/or a target of oxidative stress, respectively. However, the invivo role of ACSL4 in inflammatory responses is not fully understood. This study sought to define the effects of ACSL4 deficiency on lipopolysaccharide (LPS)-induced systemic inflammatory responses using global Acsl4 knockout (Acsl4 KO) mice. Intraperitoneal injection of LPS-induced more severe symptoms, including diarrhea, hypothermia, and higher mortality, in Acsl4 KO mice within 24 h compared with symptoms in wild-type (WT) mice. Intestinal permeability induced 3 h after LPS challenge was also enhanced in Acsl4 KO mice compared with that in WT mice. In addition, plasma levels of some eicosanoids in Acsl4 KO mice 6 h post-LPS injection were 2- to 9-fold higher than those in WT mice. The increased mortality observed in LPS-treated Acsl4 KO mice was significantly improved by treatment with the general cyclooxygenase inhibitor indomethacin with a partial reduction in the severity of illness index for hypothermia, diarrhea score, and intestinal permeability. These results suggest that ACSL4 deficiency enhances susceptibility to endotoxin at least partly through the overproduction of cyclooxygenase-derived eicosanoids.

Trade-Offs among Immune Mechanisms: Bacterial-Challenged Spodoptera frugiperda Larvae Reduce Nodulation Reactions during Behavioral Fever.

Insect innate immunity is composed of cellular and humoral reactions, the former acting via circulating hemocytes and the latter via immune signaling that lead to the production of antimicrobial peptides and phenol oxidase-driven melanization. Cellular immunity involves direct interactions between circulating hemocytes and invaders; it includes internalization and killing microbes (phagocytosis) and formation of bacterial-laden microaggregates which coalesce into nodules that are melanized and attached to body walls or organs. Nodulation can entail investing millions of hemocytes which must be replaced. We hypothesized that biologically costly hemocyte-based immunity is traded off for behavioral fevers in infected larvae of fall armyworms, Spodoptera frugiperda, that were allowed to fever. We tested our hypothesis by infecting larvae with the Gram-negative bacterium, Serratia marcescens, placing them in thermal gradients (TGs) and recording their selected body temperatures. While control larvae selected about 30 °C, the experimental larvae selected up 41 °C. We found that 4 h fevers, but not 2, 6 or 24 h fevers, led to increased larval survival. Co-injections of S. marcescens with the prostaglandin (PG) biosynthesis inhibitor indomethacin (INDO) blocked the fevers, which was reversed after co-injections of SM+INDO+Arachidonic acid, a precursor to PG biosynthesis, confirming that PGs mediate fever reactions. These and other experimental outcomes support our hypothesis that costly hemocyte-based immunity is traded off for behavioral fevers in infected larvae under appropriate conditions.

Diuretic, Natriuretic, And Ca2+-Sparing Effect Of The Alkaloid Boldine In Rats

Abstract Background Previous studies indicate the renal vasodilating effects of boldine, an alkaloid found in Peumus boldus. However, its potential to induce diuresis still needs to be studied. Methods Wistar rats were used and the urine volume was noted for 8 h and further studied. Results The acute treatment at 0.1 and 0.3 mg/kg of boldine showed a diuretic, natriuretic, and Ca2+-sparing effect in rats without changing the urinary elimination of K+and Cl-. When boldine was given in combination with hydrochlorothiazide, there was an increase in urinary volume compared to the vehicle group. However, this was not different from the treatments in its isolated form. Urine Ca2+values ​​remained low but were not enhanced by this association. The excretion of Na+and Cl- was significantly increased compared to the group that received only vehicle or boldine. On the other hand, although the association of amiloride plus boldine did not result in a diuretic effect, the increase in Na+and the reduction in K+excretion were significantly potentiated. Furthermore, in the presence of the non-selective muscarinic receptor antagonist atropine, boldine showed reduced capacity to increase urinary volume, maintaining the natriuretic and Ca2+-sparing effect, besides a very evident K+-sparing action. Similar results were obtained in the presence of the non-selective cyclooxygenase inhibitor indomethacin. Furthermore, boldine showed an ex vivo antiurolithiasis activity, reducing calcium oxalate’s precipitation and crystallization. Conclusions This study reveals the diuretic, natriuretic, Ca2+-sparing, and antiurolithiatic effects of boldine, an action possibly related to muscarinic receptor activation and prostanoid generation.

Prostaglandin F2α synthase promotes oxaliplatin resistance in colorectal cancer through prostaglandin F2α-dependent and F2α-independent mechanism.

Oxaliplatin (Oxa) is the first-line chemotherapy drug for colorectal cancer (CRC), and Oxa resistance is crucial for treatment failure. Prostaglandin F2α synthase (PGF2α) (PGFS), an enzyme that catalyzes the production of PGF2α, is involved in the proliferation and growth of a variety of tumors. However, the role of PGFS in Oxa resistance in CRC remains unclear. To explore the role and related mechanisms of PGFS in mediating Oxa resistance in CRC. The PGFS expression level was examined in 37 pairs of CRC tissues and paracancerous tissues at both the mRNA and protein levels. Overexpression or knockdown of PGFS was performed in CRC cell lines with acquired Oxa resistance (HCT116-OxR and HCT8-OxR) and their parental cell lines (HCT116 and HCT8) to assess its influence on cell proliferation, chemoresistance, apoptosis, and DNA damage. For determination of the underlying mechanisms, CRC cells were examined for platinum-DNA adducts and reactive oxygen species (ROS) levels in the presence of a PGFS inhibitor or its products. Both the protein and mRNA levels of PGFS were increased in the 37 examined CRC tissues compared to the adjacent normal tissues. Oxa induced PGFS expression in the parental HCT116 and HCT8 cells in a dose-dependent manner. Furthermore, overexpression of PGFS in parental CRC cells significantly attenuated Oxa-induced proliferative suppression, apoptosis, and DNA damage. In contrast, knockdown of PGFS in Oxa-resistant HCT116 and HCT8 cells (HCT116-OxR and HCT8-OxR) accentuated the effect of Oxa treatment in vitro and in vivo. The addition of the PGFS inhibitor indomethacin enhanced the cytotoxicity caused by Oxa. Treatment with the PGFS-catalyzed product PGF2α reversed the effect of PGFS knockdown on Oxa sensitivity. Interestingly, PGFS inhibited the formation of platinum-DNA adducts in a PGF2α-independent manner. PGF2α exerts its protective effect against DNA damage by reducing ROS levels. PGFS promotes resistance to Oxa in CRC via both PGF2α-dependent and PGF2α-independent mechanisms.

Relaxation Effect of Schisandrol A on Isolated Thoracic Aorta and its Mechanism in Rats

Background Schisandra chinensis (S. chinensis) is a drug commonly used in the clinical treatment of cardiovascular diseases in Traditional Chinese Medicine. However, the specific components and mechanisms of its action are still unclear. We screened six kinds of lignans from S. chinensis with high content and found that schisandrol A and schisantherin A had a strong vasorelaxant effect. The purpose of this study was to investigate the relaxation and underlying mechanism of schisandrol A in the isolated thoracic aorta of rats. Materials and Methods Isolated rat endothelium-intact and endothelium-removed thoracic aorta strips were pre-constricted with phenylephrine (PE), and the relaxation of schisandrol A on the strips was observed. Then, the mechanism was explored by pre-incubating the strips with nitric oxide synthetase inhibitor Nɷ-nitro-l-arginine methyl ester (L-NAME), cyclooxygenase inhibitor (indomethacin), potassium channel blockers 4-aminopyridine (4-AP), barium chloride (BaCl2), tetraethylamine (TEA), and glibenclamide, respectively, and changing the calcium concentration in the bath. In addition, expressions of endothelial nitric oxide synthetase (eNOS) mRNA and protein in rat thoracic aorta were detected. Results Schisandrol A induced both endothelium-dependent and endothelium-independent relaxation of isolated thoracic aorta strips of rats, and the mechanism might be related to promoting the synthesis of NO, inhibiting Ca2+ release from the sarcoplasmic reticulum, and blocking the Ca2+ channels. Conclusion These discoveries may provide a theoretical basis for the traditional application of S. chinensis to treat cardiovascular disease.

Cilostazol induces vasorelaxation through the activation of the eNOS/NO/cGMP pathway, prostanoids, AMPK, PKC, potassium channels, and calcium channels

ObjectiveThis study aimed to investigate vasoactive effect mechanisms of cilostazol in rat thoracic aorta. Materials and methodsThe vessel rings prepared from the thoracic aortas of the male rats were placed in the chambers of the isolated tissue bath system. The resting tone was adjusted to 1 g. Following the equilibration phase, potassium chloride or phenylephrine was used to contract the vessel rings. When achieving a steady contraction, cilostazol was applied cumulatively (10−8–10−4 M). In the presence of potassium channel blockers or signaling pathway inhibitors, the same experimental procedure was performed. ResultsCilostazol exhibited a significant vasorelaxant effect in a concentration-dependent manner (pD2: 5.94 ± 0.94) (p < .001). The vasorelaxant effect level of cilostazol was significantly reduced by the endothelial nitric oxide synthase inhibitor L-NAME (10−4 M), soluble guanylate cyclase inhibitor methylene blue (10 µM), cyclooxygenase 1/2 inhibitor indomethacin (5 µM), adenosine monophosphate-activated protein kinase inhibitor compound C (10 µM), non-selective potassium channel blocker tetraethylammonium chloride (10 mM), large-conductance calcium-activated potassium channel blocker iberiotoxin (20 nM), voltage-gated potassium channel blocker 4-Aminopyridine (1 mM), and inward-rectifier potassium channel blocker BaCl2 (30 µM) (p < .001). Moreover, incubation of cilostazol (10−4 M) significantly reduced caffeine (10 mM), cyclopiazonic acid (10 µM), and phorbol 12-myristate 13-acetate-induced (100 µM) vascular contractions (p < .001). ConclusionsIn the rat thoracic aorta, the vasodilator action level of cilostazol is quite noticeable. The vasorelaxant effects of cilostazol are mediated by the eNOS/NO/cGMP pathway, prostanoids, AMPK pathway, PKC, potassium channels, and calcium channels.

Influence of obesity on the tone of bronchial smooth muscles in rats

Background. Overweight and obesity are key factors for the occurrence of many morphofunctional disorders in organs and tissues, including bronchopulmonary system.The aim. To study the influence of metabolic disorders that occur against the background of obesity on the state of the airways tone in rats.Materials and methods. Obesity in male Wistar rats was induced using a high-fat and high-carbohydrate diet. In animals, body weight and fat mass were measured, and the heart-lung complex was extracted. In blood serum, the levels of glucose, insulin, leptin, triglycerides, and cholesterol were assessed. Bronchoalveolar lavage fluid was obtained by an open method, in which the concentration of protein, interleukin (IL) 6 and IL-10 was determined. The contractile activity of the isolated bronchial smooth muscle segments was studied using mechanographic method. The effect of acetylcholine (10–7–10–4 M), indomethacin (10–5 M), and forskolin (10–7–10–5 M) on the changes in the tone of airway smooth muscles was assessed.Results. High-fat and high-carbohydrate diet caused an increase in body weight, visceral obesity, hyperglycemia, insulin resistance, leptinemia, dyslipidemia in rats of the experimental group. In the bronchoalveolar lavage fluid of experimental animals, an increase in the content of protein and IL-6 was found, which positively correlated with the level of leptin and the fat mass. In obese rats, the contractile responses of bronchial smooth muscle segments increased in response to the effect of the cholinergic agent acetylcholine. The bronchoconstrictor effect of acetylcholine was reduced by the cyclooxygenase inhibitor indomethacin. In turn, the adenylate cyclase activator forskolin caused relaxation of the airway segments smooth muscles in rats of both groups, which was more pronounced in the experimental group.Conclusion. The obtained results indicate that the change in the reactivity of the respiratory tract can be the cause of bronchospastic conditions in obesity and of the inflammatory reaction in the respiratory system induced by obesity.

Screening of anti-functional dyspepsia compounds in Cynanchum auriculatum: A spectrum-effect relationship analysis, and ATP-binding cassette transporters inhibitor evaluation

Ethnopharmacological relevanceFunctional dyspepsia (FD) is a disorder caused by abnormal gut–brain axis regulation and is highly prevalent in China. Cynanchum auriculatum (CA) is often used to treat FD in the ethnic minority areas of Guizhou. Although several CA-based products are currently available in the market, it is unclear which components of CA are efficacious and what their oral absorption mechanism is. Aim of the studyThis study aimed to screen anti-FD components of CA based on the spectrum-effect relationship. In addition, the study evaluated the intestinal absorption mechanism of these components using transporter inhibitors. Materials and methodsThe fingerprinting of compounds from CA extract and plasma after oral administration was conducted using ultra-high-performance liquid chromatography quadrupole-time-of-flight tandem mass spectrometry (UHPLC-Q-TOF-MS). The intestinal contractile parameters were then measured in vitro using the BL-420F Biofunctional Experiment System. Multivariate statistical analysis of the result of spectrum-effect relationship assessment was used to elucidate the correlation between prominent peaks of CA-containing plasma and intestinal contractile activity. The effect of ATP-binding cassette (ABC) transporter inhibitors, such as the P-gp inhibitor verapamil, the MRR inhibitor indomethacin, and the BCRP inhibitor Ko143, on the directional transport of the predicted active ingredients was assessed in vivo. ResultsTwenty chromatographic peaks were identified in the CA extract. Of these, three were C21 steroids, four were organic acids, and one was a coumarin, and acetophenone by comparing with reference compounds. Additionally, it is discovered that there are totally 39 migratory components in CA-containing plasma, which was found to significantly promote the contractility of the isolated duodenum. Moreover, multivariate analysis of the spectrum-effect relationship demonstrated that 16 characteristic peaks (3, 6, 8, 10, 11, 13, 14, 18, 21, m1–m4, m7, m15, and m24) in CA-containing plasma were significantly associated with the anti-FD effect. These compounds included seven prototype compounds, i.e., cynanoneside A, syringic acid, deacylmetaplexigenin, ferulic acid, scopoletin, baishouwubenzophenone, and qingyangshengenin. The inhibition of ABC transporters demonstrated that the inhibitors verapamil and Ko143 significantly increased (P < 0.05) the uptake of scopoletin and qingyangshengenin. Thus, these compounds may be substrates for P-gp and BCRP. ConclusionsThe potential anti-FD components of CA and the effect of ABC transporter inhibitors on these active components were preliminarily clarified. These findings lay a foundation for subsequent in vivo studies.