Search Results (164)

Background/Objectives: This 7-day rat tracheocutaneous fistula study considered the not-studied issues of tracheocutaneous fistula course, wound healing, and fistula in the NO-system relations. Therefore, we focused on fistulas’ severe course, tracheocutaneous fistula → air leak → compensatory diaphragmatic/abdominal “heaving”, NO-system failed relations, and therapy resolution. Stable gastric pentadecapeptide BPC 157 was proposed. Methods: Tracheocutaneous fistula rats received daily medication (/kg), alone or combined, BPC 157 therapy (10 µg, 10 ng, in drinking water or intraperitoneally) along with a triple NO-agent approach (L-NAME 5 mg, L-arginine 100 mg, and L-NAME+L-arginine, intraperitoneally). Results: Tracheocutaneous fistulas occurred as specific and NO-system-related as follows: NO system: blockade (L-NAME-aggravation) over-activity (L-arginine-amelioration) or immobilization (L-NAME+L-arginine oppose each other’s effects). Controls presented severe clinical signs of respiratory distress, failed healing, skin and tracheal defects, a not-healed and open, macro/microscopically, and fistulous tract that was well-formed and wide, tracheal shrinking below the fistula, and clinically, open-mouth breathing, “heaving abdomen”, cyanosis (bluish snout, ears, extremities), abundant secretion through the fistula, and weight loss. Fistula tissue NO level decreased, and the malondialdehyde (MDA) level increased. The BPC 157 therapy (both application routes) resulted in rapid recovery. Healing of defects (skin and trachea) and fistula closure, macro/microscopically, corresponded with clinical findings, avoiding observable clinical signs of dyspnea, reducing weight loss, and avoiding any sign of “heaving abdomen”. BPC 157-treated rats displayed regular breathing movements without observable signs of respiratory distress. Finally, when combined, BPC 157 therapy upgrades L-arginine amelioration, abolishes L-NAME-induced worsening, and restores full healing after NO immobilization (L-NAME+L-arginine). BPC 157 counteracted increase in NO level and counteracted increase in MDA level. Conclusions: Thus, first, acting systemically, BPC 157 reverses tracheocutaneous fistula course in rats. It acts through the NO system. Full article

Excessive oxidative stress within the renal medulla is implicated in the development of hypertension, potentially modulated by renal nerve stimulation (RNS). This study examined the effects of RNS on cortical and medullary blood perfusion in Stroke-Prone Spontaneously Hypertensive Rats (SHRSP) under both normal conditions and at varying levels of oxidative stress. Male SHRSP rats were assigned to five experimental groups and subjected to RNS at different frequencies, with infusions of vehicle, tempol, tempol plus catalase (tem + cat), diethyldithiocarbamic acid (DETC), or L-nitro-arginine methyl ester (L-NAME) at the renal cortico-medullary border (CMB). Regional blood perfusion of the renal cortex and medulla (CBP and MBP, respectively) was assessed using Laser-Doppler flowmetry. RNS significantly reduced CBP and MBP by 43 ± 8% and 23 ± 4%, respectively, at 8 Hz. Co-infusion of tempol plus catalase significantly attenuated the RNS-induced reductions in both CBP and MBP. Similarly, DETC infusion mitigated RNS-induced decreases in CBP and MBP. In contrast, tempol alone and L-NAME did not protect against the RNS-induced under-perfusion of the renal cortex and medulla. The results suggest that simultaneous removal of superoxide anion and hydrogen peroxide (H₂O₂) can alleviate the reduction in renal blood perfusion caused by RNS, emphasizing a crucial role for H₂O₂ in renal hemodynamic regulation. Interestingly, DETC, which is expected to elevate superoxide anion levels, also mitigated RNS-induced under-perfusion, suggesting the presence of a potentially novel indirect protective mechanism that warrants further investigation. Full article

Neuropathic pain (NPP) remains therapeutically challenging, with oxidative/nitrosative stress and neuroinflammation—amplified by nitric oxide (NO)—as key drivers. This study investigated geraniin (GRN), a naturally occurring hydrolyzable ellagitannin widely distributed in various plant species, including Phyllanthus spp. and Nephelium lappaceum (rambutan), in a rat model of sciatic nerve chronic constriction injury (CCI), focusing on NO-pathway involvement. Male Wistar rats (n = 8/group) received intraperitoneal GRN (3, 10, 30, or 100 mg/kg) or vehicle (1% DMSO in saline) daily for 21 days. Behavioral (thermal hyperalgesia, mechanical allodynia, sciatic functional index), electrophysiological (nerve conduction velocity), and biochemical markers—oxidative/nitrosative stress (nitrite, MDA), antioxidant defenses (GSH, SOD, CAT), inflammation (TNF-α, IL-1β, IL-6, MPO), and apoptosis (caspase-3)—were quantified. L-arginine or L-NAME was co-administered to probe NO signaling. GRN at 30 and 100 mg/kg produced significant antinociceptive and neuroprotective effects; 30 mg/kg was selected for detailed analysis. By day 21, GRN improved pain thresholds and nerve conduction, enhanced antioxidant capacity, suppressed inflammatory mediators, and reduced caspase-3 activity. L-arginine reversed, whereas L-NAME potentiated these effects, confirming NO-dependent modulation. Collectively, GRN mitigates CCI-induced NPP via coordinated antioxidant, anti-inflammatory, and anti-apoptotic actions, supporting its potential as a multi-target candidate for pharmacokinetic and translational development. Full article

Primary dysmenorrhea (PDM) is a typical gynecologic disease in which uterine contractions and inflammation cause pain. Stachydrine (Sta) possesses multiple pharmacological activities but its effect on PDM has not yet been clarified. In vitro uterine contraction and oxytocin (OT)-induced PDM mouse models were used to evaluate the effect of Sta. Sta (10^−6.5 to 10⁻⁴ mol/L) dose-dependently inhibited spontaneous and OT-induced uterine contractions, with maximum inhibition rates of 47.1% and 40.4%, respectively. This effect was reversed by N-nitro-L-arginine (L-NAME) and indomethacin (Indo), suggesting the involvement of the nitric oxide and prostaglandin pathways. In vivo, Sta (20, 10, 5 mg/kg) significantly reduced writhing episodes, prolonged latency to the first response, and alleviated OT-induced uterine damage and inflammation. Additionally, Sta downregulated cyclooxygenase-2 (COX-2) expression in uterine tissue and decreased serum malondialdehyde (MDA) and prostaglandin F₂α (PGF2α) levels. These findings suggest that Sta alleviates PDM by modulating the COX-2/PGF2α pathway, inhibiting uterine contractions, and reducing inflammation and oxidative stress, making it a promising therapeutic candidate for PDM. Full article

Depression is a prevalent psychiatric disorder in which oxidative stress and nitric oxide (NO) signaling have been implicated. Natural compounds such as Punica granatum have shown potential antidepressant effects, but their mechanisms remain unclear. This study aimed to evaluate the antidepressant-like effects of an aqueous extract of P. granatum in male Swiss Webster mice and to explore the possible involvement of NO-related system. Acute administration of P. granatum (0.25–2 mg/kg, i.p.) was tested in the forced swim and tail suspension tests. The interaction with NO signaling was examined through co-administration with an NO donor (sodium nitroprusside, SNP) and NOS inhibitors (NG-nitro-L-arginine methyl ester, L-NAME and 7-nitroindazole, 7-NI). Biochemical markers of oxidative stress (lipid peroxidation and GSH/GSSG ratio) were also assessed. P. granatum significantly reduced immobility and increased swimming behavior, consistent with an antidepressant-like effect. SNP, L-NAME, and 7-NI induced pro-depressant effects, which were prevented by P. granatum co-administration. Treatment also attenuated oxidative stress markers in the hippocampus and prefrontal cortex. These findings suggest that the antidepressant-like effects of P. granatum may involve interactions with NO signaling, although this interpretation remains indirect, as specific NO pathway indices were not measured. Acute P. granatum administration exerts antidepressant-like and antioxidant effects in male mice. The results support its potential as a natural candidate for depression treatment, particularly in conditions associated with oxidative imbalance and possible NO dysregulation. Future studies should confirm these mechanisms using direct molecular assessments and include female cohorts. Full article

Background/Objectives: The rapid progression of stroke often results in irreversible brain damage and poor outcomes when treatment is delayed. Prophylactic administration of FAD012 (3,5-dimethyl-4-hydroxycinnamic acid), a synthetic derivative of ferulic acid (FA), has demonstrated cerebroprotective effects in ischemic models through antioxidant and endothelial protective mechanisms. This study investigated the effects of FAD012 on cerebral infarction and blood–brain barrier (BBB) integrity using a photothrombotic stroke model in rats. Methods: Male Sprague Dawley rats received a single intraperitoneal injection of FAD012 or FA (100 or 300 mg/kg) 60 min prior to stroke induction. Under isoflurane anesthesia, the middle cerebral artery was exposed, and stroke was induced by intravenous administration of Rose Bengal followed by green laser irradiation. Cerebral blood flow (CBF) was monitored by laser Doppler flowmetry. BBB disruption was evaluated by Evans Blue extravasation and immunohistochemistry for tight junction (TJ) proteins. Results: Control rats exhibited extensive infarction, BBB disruption, and reduced expression of claudin-5, occludin, and ZO-1, along with fragmented collagen IV. In contrast, FAD012 (300 mg/kg) significantly attenuated CBF reduction, reduced infarct size, preserved BBB integrity, and maintained TJ protein expression, with greater efficacy than an equivalent dose of FA. FAD012 also preserved the expression and phosphorylation of endothelial nitric oxide synthase (eNOS), a key marker of vascular integrity. The CBF-preserving effect of FAD012 was completely abolished by N^G-nitro-L-arginine methyl ester (L-NAME), a nitric oxide synthase inhibitor. Conclusions: These findings suggest that FAD012 protects endothelial function, thereby contributing to the maintenance of CBF and BBB integrity, supporting its potential as a prophylactic therapeutic agent for ischemic stroke. Full article

Background/Objectives: Nelumbo nucifera Gaertn. (lotus) seeds have traditionally been used to treat hypertension, though their mechanisms remain unclear. This study investigated the antihypertensive effects of lotus seed extract (LSE) and its mechanisms in rats with N^ω-nitro-L-arginine methyl ester (L-NAME)-induced hypertension. Methods: Male Sprague Dawley rats received L-NAME (40 mg/kg/day) in drinking water and were treated orally with LSE (5, 10, or 100 mg/kg/day), captopril (5 mg/kg/day), or a combination of LSE and captopril (2.5 mg/kg/day each) for 5 weeks. Hemodynamic parameters and histological changes in the left ventricle and aorta were assessed. Mechanistic studies included measurements of plasma nitric oxide (NO) metabolites, malondialdehyde (MDA), superoxide dismutase (SOD) activity, angiotensin II (Ang II), angiotensin-converting enzyme (ACE) activity, and protein expression via western blot. Results: L-NAME elevated systolic blood pressure and induced cardiovascular remodeling, oxidative stress, and renin-angiotensin system activation. LSE treatment reduced blood pressure, improved antioxidant status, increased NO bioavailability, and downregulated gp91^phox and AT₁R expression. The combination of low-dose LSE and captopril produced stronger effects than LSE alone, with efficacy comparable to captopril. Conclusions: These findings suggest that LSE exerts antihypertensive effects via antioxidant activity and inhibition of the renin-angiotensin system, supporting its potential as an adjunct therapy for hypertension. Full article

Although nitric oxide (NO) production in bacteria has traditionally been associated with denitrification or stress responses in model or symbiotic organisms, functionally validated L-arginine-dependent nitric oxide synthase (bNOS) activity has not been documented in free-living, non-denitrifying soil bacteria. This paper reports Paenibacillus nitricinens sp. nov., a bacterium isolated from rainforest soil capable of synthesizing NO via a bNOS under aerobic conditions. A bnos-specific PCR confirmed gene presence, while whole-genome sequencing (6.7 Mb, 43.79% GC) revealed two nitrogen metabolism pathways, including a bnos-like gene. dDDH (<70%) and ANI (<95%) values with related Paenibacillus strains support the delineation of this isolate as a distinct species. Extracellular and intracellular NO measurements under aerobic conditions showed a dose-dependent response, with detectable production at 0.1 µM L-arginine and saturation at 100 µM. The addition of L-NAME reduced NO formation, confirming enzymatic mediation. The genomic identification of a bnos-like gene strongly supports the presence of a functional pathway. The absence of canonical nitric oxide reductase (Nor) genes or other typical denitrification-related enzymes reinforces that NO production arises from an alternative, intracellular enzymatic mechanism rather than classical denitrification. Consequently, P. nitricinens expands the known repertoire of microbial NO synthesis and suggests a previously overlooked source of NO flux in well-aerated soils. Full article

Heart failure with preserved ejection fraction (HFpEF) is increasingly recognized as a systemic disorder, often coexisting with chronic obstructive pulmonary disease (COPD). This study aims to identify the shared pathogenic mechanisms between HFpEF and COPD and validate them in an experimental HFpEF model. Transcriptomic datasets from HFpEF cardiac tissue and COPD lung tissue were analyzed using differentially expressed gene (DEG) analysis, weighted gene co-expression network analysis (WGCNA), and functional enrichment analysis. Key genes were identified through least absolute shrinkage and selection operator (LASSO) regression. Immune cell infiltration was assessed using xCell and CIBERSORT, and single-cell RNA sequencing (scRNA-seq) was utilized to determine gene expression patterns across different cell populations. A high-fat diet and N[w]-nitro-L-arginine methyl ester (L-NAME)-induced HFpEF mouse model was established, and the expression of SESN3 and autophagy-related markers was evaluated in both cardiac and pulmonary tissues using immunofluorescence, quantitative PCR (qPCR), Western blotting (WB), and transmission electron microscopy. DEG and WGCNA analyses identified 1243 and 131 core genes in HFpEF and COPD, respectively. Functional enrichment analysis highlighted autophagy as a common regulatory pathway in both conditions. Among the nine intersecting genes, SESN3 was identified as a key candidate through LASSO regression. Immune infiltration analysis and scRNA-seq further demonstrated the involvement of SESN3 in both cardiac and pulmonary pathophysiology. In vivo experiments showed that HFpEF mice exhibited significant lung injury. Furthermore, SESN3 upregulation and autophagy dysregulation were observed in both heart and lung tissues, supporting a potential systemic role of SESN3-mediated autophagy in HFpEF-related pulmonary alterations. This study suggests that SESN3-mediated autophagy may represent a shared mechanism between HFpEF and COPD. Our findings suggest that HFpEF may be associated with pulmonary alterations beyond cardiac dysfunction alone. These results provide novel insights into the potential multi-organ involvement in HFpEF and support the role of SESN3 as a shared molecular target in both cardiac and pulmonary pathologies. Full article

Background/Objectives: Carvacrol is a naturally occurring phenolic monoterpene that is one of the main constituents of the essential oils of oregano (Origanum vulgare) and other herbs. Carvacrol has anti-inflammatory and antinociceptive effects. Carvacrol can activate and inhibit several second messengers and ionic channels at the systemic level. However, there is no evidence of the peripheral antinociception of carvacrol and its mechanism of action. This study was designed to determine whether the opioid receptor-nitric oxide (NO)-cyclic guanosine monophosphate (cGMP)-K⁺ channel pathway is involved in the local antinociception of carvacrol. Methods: Wistar rats were injected with 1% formalin subcutaneously on the dorsal surface of the right hind paw with the vehicle or carvacrol (100–300 µg/paw). To determine whether the opioid receptor-NO-cGMP-K⁺ channel pathway and a biguanide-dependent mechanism are responsible for the local antinociception induced by carvacrol, the effect of the injection (10 min before the 1% formalin injection) with the corresponding vehicles, metformin, naltrexone, NG-L-nitro-arginine methyl ester (L-NAME), 1 H-(1,2,4)-oxadiazolo (4,2-a) quinoxalin-1-one (ODQ), and K⁺ channel blockers on the antinociception induced by local carvacrol (300 µg/paw) was determined. Results: In both phases of the formalin test, carvacrol produced antinociception. Naltrexone, metformin, L-NAME, ODQ, glibenclamide and glipizide (both ATP-sensitive K⁺ channel blockers), tetraethylammonium and 4-aminopyridine (voltage-gated K⁺ channel blockers), and apamin and charybdotoxin (Ca²⁺-activated K⁺ channel blockers) reversed the carvacrol-induced peripheral antinociception. Conclusions: The local peripheral administration of carvacrol produced significant antinociception and activated the opioid receptor-NO-cGMP-K⁺ channel pathway. Full article

Background: Preeclampsia is a leading cause of maternal and fetal morbidity and mortality, with obesity recognised as a significant risk factor. However, the direct contribution of obesity to the pathophysiology underpinning preeclampsia remains unclear. Objectives: This study aimed to develop and characterise a diet-induced obese mouse model with superimposed preeclampsia to better understand the impact of obesity on disease pathogenesis. Methods: Female mice were fed either standard rodent chow or a high-fat diet from weaning. At 8 weeks of age, mice were mated. Pregnant mice were treated with L-N^G-Nitro arginine methyl ester (L-NAME; to block nitric oxide production) from gestational day (D)7.5 to D17.5 to induce a preeclampsia-like phenotype. Blood pressure was measured on D14.5 and D17.5, followed by the collection of maternal and fetal tissues for histological, biochemical, and molecular analyses. Results: Obese dams exhibited significantly increased body, fat pad, and liver weights compared to lean controls. While L-NAME induced hypertension in the control mice, contrary to expectations, the L-NAME-induced hypertension was partially attenuated in obese dams, with significantly lower systolic and diastolic blood pressures at D14.5 and reduced systolic pressure at D17.5. Fetal weights were comparable between groups, however, placentas were significantly heavier with obesity. Endothelial function, inflammatory markers, and renal gene expression patterns suggested distinct physiological adaptations in obese preeclamptic-like mice. Conclusions: These findings challenge the prevailing assumption that obesity drives hypertension, endothelial dysfunction, and inflammatory markers. The differential vascular and physiological responses observed in the obese dams highlight the complexity of obesity–preeclampsia interactions and underscore the need for refined preclinical models to disentangle mechanistic contributions. This work has implications for personalised management strategies and targeted therapeutic interventions in obese pregnancies at risk of preeclampsia. Full article

Homeostasis is the self-regulating processes in cells and organisms designed to maintain stability of the internal environment while adjusting to external changes. To achieve this dynamic stability, internal conditions oscillate within tightly regulated physiological tolerance limits. In mammals, maintaining nitric oxide (NO) availability appears crucial to sustain relatively constant blood flow into all organs and tissues. We hypothesize that NO homeostasis is one of the most important vital processes for warm-blooded animals. It is impossible to conserve the stability of most other vital substances, such as O₂, CO₂, blood sugar, pH, and temperature, to name just few, without well-functioning tissue perfusion. NO in mammals is generated either from L-arginine by nitric oxide synthases (NOSs) or by the reduction of nitrate (NO₃⁻) to nitrite (NO₂⁻) and NO by several proteins. Here we first discuss the organization of these two NO metabolic pathways, emphasizing that both pathways “cross” and “funnel” unused NO into the overall nitrate-nitrite–NO pathway. This pathway is cyclic, which gives nitrate a unique place in metabolism and predisposes it as a reservoir for NO. Then, we discuss the role of NO homeostasis that, by maintaining organ and tissue perfusion, supports and preserves constancy of other blood-delivered substances. This “governing” role of NO makes even clearer that the existence of NO storage and precursor molecules is necessary, to avoid NO shortages in cases of the precursor’s or storage molecule’s temporary unavailability, to ensure uninterrupted tissue access to NO. We propose that the skeletomuscular system and skin act as nitrate reservoirs assuring NO bioavailability at various external and internal conditions. Full article

Facial nerve injury (FNI) induces complex molecular and cellular responses, with reactive oxygen species (ROS) and free radicals (FRs) playing pivotal roles in nerve degeneration and regeneration. However, to date, no systematic review has specifically investigated the involvement of ROS and FRs in FNI. To address this unmet need, we reviewed the literature on the subject, comprehensively searching SCOPUS, PubMed, Cochrane Library, EMBASE, and Google Scholar to identify studies that assessed the roles of FRs and ROS in FNI and summarize their findings. A total of 15 studies that satisfied search criteria were identified. Key findings showed that excessive ROS and FR lead to mitochondrial dysfunction, lipid peroxidation, and ferroptosis, exacerbating nerve degeneration after facial nerve injury. These effects are modulated by antioxidants, including alpha-lipoic acid, edaravone, N(ω)-nitro-L-arginine methyl ester (L-NAME), glutathione peroxidase 4, glutathione, methylprednisolone sodium succinate, Si-based agents, superoxide dismutase, and tirilazad mesylate. The insights gained from this review suggest that levels of FRs and ROS are strongly associated with the pathophysiology of facial nerve injury and underscore the therapeutic potential of targeting ROS and FR pathways in facial nerve injuries. Full article

The dried root of Sanguisorba officinalis L. (commonly known as Diyu) has been studied for its various pharmacological effects, including its antibacterial, antitumor, antioxidant, and anti-inflammatory activities. In the present study, primary cultured vascular endothelial cells (HUVECs) and isolated phenylephrine-precontracted rat thoracic aortic rings were examined to investigate the possible mechanism of a butanol extract of Diyu (BSO) in its vascular relaxant effect. HUVECs treated with BSO produced a significantly higher amount of nitric oxide (NO) compared to the control. However, its production was inhibited by pretreatment with N^G-nitro-L-arginine methylester (L-NAME) or wortmannin. BSO also increased the phosphorylation levels of endothelial nitric oxide synthase (eNOS) and Akt. In the aortic ring, BSO relaxed PE-precontracted rat thoracic aortic rings in a concentration-dependent manner. The absence of the vascular endothelium significantly attenuated BSO-induced vasorelaxation. The non-selective NOS inhibitor, L-NAME, and the selective inhibitor of soluble guanylyl cyclase (sGC), 1H-[1,2,4]-oxadiazolo-[4,3-α]-quinoxalin-1-one (ODQ), dramatically inhibited the BSO-induced relaxation effect of the endothelium-intact aortic ring. Ca²⁺-free buffer and intracellular Ca²⁺ homeostasis regulators (TG, Gd³⁺, and 2–APB) inhibited BSO-induced vasorelaxation. In Ca²⁺-free Krebs solution, BSO markedly reduced PE-induced contraction. Vasodilation induced by BSO was significantly inhibited by wortmannin, an inhibitor of Akt. Pretreatment with the non-selective inhibitor of Ca²⁺-activated K⁺ channels (K_Ca), tetraethylammonium (TEA), significantly attenuated the BSO-induced vasorelaxant effect. Furthermore, BSO decreased the systolic blood pressure and heart rate in a concentration-dependent manner in rats. In conclusion, BSO induces vasorelaxation via endothelium-dependent signaling, primarily through the activation of the PI3K-Akt-eNOS-NO signaling pathway in endothelial cells, and the activation of the NO-sGC-cGMP-K⁺ channels pathway in vascular smooth muscle cells. Additionally, store-operated Ca²⁺ entry (SOCE)-eNOS pathways and the inhibition of Ca²⁺ mobilization from intracellular stores contribute to BSO-induced vasorelaxation. Full article

Heat stress has become a significant concern in animal husbandry, as it adversely affects reproductive performance, particularly sperm quality, through mechanisms that are not fully understood. This study aimed to investigate the protective effects of L-arginine against heat stress-induced sperm damage and explore its potential mechanisms through the modulation of the intestinal microbiota. This study consisted of two experiments. First, in a heat-stressed mouse model, L-arginine was administered to evaluate its effects on the reproductive health of heat-stressed mice. In the second experiment, by transplanting L-arginine-induced changes in the gut microbiota into heat-stressed mice, the protective effects of the microbiota on the sperm of heat-stressed mice were assessed. The findings revealed a significant amelioration of decreased sperm quality and testicular injury induced by heat stress. Post heat stress, mice supplemented with L-arginine presented an increase in seminal vesicle gland weight and index, partial alleviation of testicular tissue morphology, and a substantial increase in testosterone concentration (p < 0.05). Additionally, L-arginine upregulated the expression of testosterone synthesis genes and the mRNA levels of sperm generation-related genes, including 3β-HSD, Stra8, WT1, and Gdnf (p < 0.05). Concurrently, L-arginine-induced microbial communities mitigated heat stress-induced decreases in sperm quality and testicular injury, coupled with increases in the mRNA expression levels of Cyp17a1, 17β-HSD, Plzf, and Gdnf (p < 0.05). Furthermore, there was a reduction in the expression of proinflammatory factors, namely, NFκB, MyD88, TNF-α, and TGF-β3 (p < 0.05). In conclusion, L-arginine may influence the ratio of beneficial bacteria to harmful bacteria in the intestinal microbiota, thereby reducing inflammation caused by heat stress, maintaining intestinal health, and influencing the microenvironment for spermatogenesis. Full article