Pretreatment with kuanxiong aerosol protects against coronary microvascular dysfunction / El pretratamiento con aerosol de kuanxiong protege contra la disfunción microvascular coronaria

This study investigates the efficacy and mechanisms of Kuanxiong Aerosol (KXA) on coronary microvascular dysfunction (CMD) in rats. Thirty-two Sprague-Dawley rats were divided into control, model, KXA, and nicorandil groups, receiving respective treatments for three weeks. The CMD model was established byinjecting lauric acid into the left ventricle. Compared to the model group, the KXA group showed significant reductions in serum CK-MB, LDH, cTnI, ET-1, TNF-α, IL-6, MDA, and ROS (p<0.01) and increased NO and SOD levels (p<0.01). KXA mitigated apoptosis and ameliorated CMD-associated pathological alterations. Pretreatment with KXA improves endothelial function and microvascular structure by counteracting inflammation, oxidative stress, and apoptosis, thereby improving CMD.

Este estudio investiga la eficacia y los mecanismos del Aerosol de Kuanxiong (KXA) sobre la disfunción microvascular coronaria (CMD) en ratas. Treinta y dos ratas Sprague-Dawley se dividieron en grupos de control, modelo, KXA y nicorandil, recibiendo los respectivos tratamientos durante tres semanas. El modelo de CMD se estableció inyectando ácido láurico en el ventrículo izquierdo. En comparación con el grupo modelo, el grupo KXA mostró reducciones significativas en los niveles séricos de CK-MB, LDH, cTnI, ET-1, TNF-α, IL-6, MDA y ROS (p<0.01) y un aumento en los niveles de NO y SOD (p<0.01). KXA mitigó la apoptosis y mejoró las alteraciones patológicas asociadas con la CMD. El pretratamiento con KXA mejora la función endotelial y la estructura microvascular al contrarrestar la inflamación, el estrés oxidativo y la apoptosis, mejorando así la CMD.

Acute glyphosate and aminomethylphosphonic acid (AMPA), its major metabolite, impaired spatial orientation, navigation, learning and/or memory in female rats.

Human exposure to glyphosate-based herbicides (GBH) has been associated with a range of toxicological effects involving the central nervous system (CNS) such as alterations in learning and memory. Nevertheless, the effects of aminomethylphosphonic acid (AMPA), the main metabolite of glyphosate, remain essentially obscure. Previous preclinical reports suggest that acute intoxication with AMPA and glyphosate exerts decrease on hippocampal acetylcholinesterase activity and produces more metabolomic alterations in the female brain over the male one. Therefore, this work explored the effects of acute AMPA and glyphosate on spatial learning, memory and navigation in female rats. Sprague Dawley rats received a single injection (i.p.) of: (i) vehicle; (ii) 10 or 100 mg/kg of AMPA; or (iii) 10 or 100 mg/kg of glyphosate; subsequently, the Barnes maze paradigm was performance. Animals from the control group decreased latency and the attempts to solve the Barnes maze; and increased the degree of orientation when compared first training sessions (S1) vs. the last one (S4; p < 0.05). In contrast, both 10 and 100 mg/kg of glyphosate and 100 mg/kg of AMPA prevented the decrease in latency and attempts; and the increase of orientation (p > 0.05; S1 vs. S4). Both treatments decreased the use of the spatial navigation strategy (p < 0.05). Besides, glyphosate at the higher dose but not AMPA impaired the spatial memory during the test. Our findings suggest that acute exposure to glyphosate and AMPA similarly affected spatial orientation, navigations, learning and/or memory.

Strontium-containing mineralized phospholipid coatings improve osseointegration in osteoporotic rats.

Surface treatments play an important role in enhancing the osseointegration of Titanium (Ti) and its alloys. This study introduces a method employing biomimetic hydroxyapatite (Hap) deposition guided by molecularly organized phospholipids, affixed to the metal implant surface. Using the Langmuir-Blodgett technique, phospholipids were deposited onto Ti-screws by using CaCl2 or CaCl2/SrCl2 aqueous solution in the subphase of a Langmuir trough in the target proportion (i.e. 10 and 90 mol% of Sr2+ in relation of Ca2+) followed by immersion in phosphate buffer and in supersaturated simulated body fluid. Coating composition and morphology were evaluated using infrared spectroscopy and scanning electron microscopy, respectively, while contact angle measurements assessed coating wettability and surface energy. Randomized screws were then implanted into the tibias of healthy and osteoporotic female rats (G1: Control-Machined, G2: Hap, G3: HapSr10, G4: HapSr90). Osseointegration, assessed 60 days post-implantation, included reverse torque, fluorochrome area, bone tissue-screw contact area, and linear extent of bone-screw contact. Results, grouped by surface treatment (Machined, Hap, HapSr10, HapSr90), revealed that the deposition of Hap, HapSr10, and HapSr90 resulted in thin and rough coatings composed of hydroxyapatite (Hap) on the screw surface with nanoscale pores. The coatings resulted in increased wettability and surface energy of Ti surfaces. The minerals are chemically similar to natural bone apatite as revealed by FTIR analysis. In vivo analyses indicated higher torque values for strontium-containing surfaces in the osteoporotic group (p = 0.02) and, in the control group superior torque for screw removal on the Hap surface (p = 0.023). Hydroxyapatite-treated surfaces enhance morphology, composition, and reactivity, promoting screw osseointegration in healthy and osteoporotic female rats. The incorporation of strontium into the mineral phase has been proposed to not only stimulate osteoblast activity but also reduce osteoclastic resorption, which may explain the improved outcomes observed here in experimental osteoporotic conditions.

Can distinct Gram-negative biofilm-forming bacteria have different impacts on ciprofloxacin lung penetration?

Literature have shown that Gram-negative bacteria release endotoxins which alter drug membrane transporters and could potentially influence antimicrobials distribution to the infection site depending on the infecting bacteria. Previously, a population pharmacokinetic (popPK) model describing ciprofloxacin (CIP) concentrations in healthy, and Pseudomonas aeruginosa pneumonic rats showed that the chronic stage of the infection significantly reduced the drug lung penetration. In this study, CIP lung penetration in Klebsiella pneumoniae chronically (14 d) infected rats following CIP 20 mg/kg i.v. bolus dosing was investigated and the popPK model developed previously was used to evaluate CIP lung exposure. Drug plasma exposure was similar for both bacteria and higher than observed in healthy animals. Probability of target attainment analysis using plasma data following current dosing regimen (20 mg q8h equivalent to 400 mg q8h in humans) showed that CIP PK/PD index (ƒAUC0-24/MIC ≥90) is achieved for the most prevalent MIC's of both bacteria. However, CIP free lung concentrations were reduced in infected animals by 46.8 % (P. aeruginosa) and 68.4 % (K. pneumoniae) in comparison to healthy animals. The higher lung clearance observed (0.306 L/h/kg) in K. pneumoniae infected animals lead to a lower free CIP lung exposure in comparison to the P. aeruginosa group (0.105 L/h/kg). In summary, although plasma PK/PD index is achieved by the current regimen, chronic pneumonia by biofilm-forming bacteria decreases lung exposure to CIP and this decrease is dependent on the infecting bacteria. The clinical relevance of this finding needs to be determined.

Traumatic brain injury, alone or with striatal hemorrhage-like extension, transiently decreases GABA and glutamate levels along motor deficits in the rat striatum: an in vivo study.

The cerebral cortex is connected to the striatum via the axons of the pyramidal glutamatergic neurons, and this pathway is intimately involved in motor function. In the striatum, glutamatergic afferents initiate the activity of GABAergic medium spiny neurons. This study addressed whether traumatic brain injury (TBI) affects GABA and glutamate extracellular levels in the dorsal striatum as an indicator of effects on the cortico-striatal pathway, in rats with motor deficits and recovered animals. Animals were assigned to a sham group, a TBI-alone group, and a TBI + striatal injury group (local injection of a FeCl2 solution to mimic hemorrhagic lesion). In the TBI-alone and TBI + striatal injury groups, motor deficits were accompanied by decreased extracellular GABA and glutamate levels in the striatum at 3 days post-injury. The TBI + striatal injury group showed higher motor deficits, which lasted 7 days longer, and GABA levels were significantly different compared to the TBI alone group. At 18 days post-injury, in recovered rats from the TBI-alone group GABA and glutamate levels returned to control levels. Alterations in extracellular GABA and glutamate levels indicate damage to the cortico-striatal pathway, underscoring the importance of studying this pathway for treatment and recovery after TBI.

Decreases in metabolic ATP open KATP channels and reduce firing in an auditory brainstem neuron: A dynamic mechanism of firing control during intense activity.

Cartwheel (CW) neurons are glycinergic interneurons in the dorsal cochlear nucleus (DCN) that exhibit spontaneous firing, resulting in potent tonic inhibition of fusiform neurons. CW neurons expressing open ATP-sensitive potassium (KATP) channels do not fire spontaneously, and activation of KATP channels halts spontaneous firing in these neurons. However, the conditions that regulate KATP channel opening in CW neurons remain unknown. Here, we tested the hypothesis that fluctuations in metabolic ATP levels modulate KATP channels in CW neurons. Using whole-cell patch-clamp recordings in CW neurons from young rat brain slices (p17-22) with an ATP-free internal solution, we observed that the mitochondrial uncoupler CCCP hyperpolarized the membrane potential, reduced spontaneous firing, and generated an outward current, which was inhibited by the KATP channel antagonist tolbutamide. Additionally, a glucose-free external solution quickly activated KATP channels and ceased spontaneous firing. We hypothesized that intense membrane ion ATPase activity during strong depolarization would deplete intracellular ATP, leading to KATP channel opening. Consistent with this, depolarizing CW neurons with a 250 pA DC did not increase spontaneous firing because the depolarization activated KATP channels; however, the same depolarization after tolbutamide administration increased firing, suggesting that ATP depletion triggered KATP channel opening to limit action potential firing. These results indicate that KATP channels in the DCN provide dynamic control over action potential firing, preventing excessive excitation during high-firing activity.

Influence of aging and maternal protein restriction on PIWI-interacting RNA expression in the offspring rat ventral prostate.

The Developmental Origins of Health and Disease (DOHaD) concept explores the link between exposure to adverse conditions during fetal and early childhood development and the onset of chronic non-communicable diseases, such as prostate cancer (PCa). Changes in epigenetics that control gene expression have been identified as potential contributors to the developmental origin of PCa. Piwi-interacting RNAs (piRNAs), for example, control transposable elements (TEs) and maintain genome integrity in germ cells. However, stress-induced deregulation of TEs warrants investigating the role of piRNAs in the prostate gland from the DOHaD perspective, which remains underexplored. This study aimed to detect and characterize piRNA expression in the ventral prostate (VP) of Sprague Dawley rat offspring at 21 postnatal days (PND21) and PND540. The rats were subjected to maternal protein restriction during pregnancy and lactation to understand its impact on prostate development and aging. Histological analyses showed that the gestational and lactation low-protein diet (GLLP) group experienced a delay in prostate gland development, with increased stromal and epithelial compartments and decreased luminal compartments during early life. Aging in this group resulted in decreased luminal compartments and increased stromal areas. Epithelial atrophy was observed in both groups, with an increased incidence of carcinoma in situ in the GLLP group. Small RNA sequencing from control and restricted groups (at PND21 and PND540) identified piRNA clusters in both young and aged animals. We also detected the expression of PIWI genes (Riwi, Rili, Rili2) in the prostate. Our data highlight the key role of maternal malnutrition in modulating piRNA expression in the offspring's VP, with the potential to influence prostate developmental biology and the risk of prostatic disorders with aging.

Implication of the enteric glia in the IBS-like colonic inflammation associated with endometriosis.

BACKGROUND: Endometriosis is a complex gynecological disorder characterized by the ectopic growth of endometrial tissue. Symptoms of endometriosis are known to impair the quality of life of patients, and among these are found dysmenorrhea, chronic pelvic pain, and gastrointestinal (GI) issues. GI issues such as painful bowel movements, bloating and constipation or diarrhea, are one of the common reasons for misdiagnosis with irritable bowel syndrome (IBS). Enteric glial cells (EGC) are known to play a role in pain associated with IBS, and reactive gliosis has been reported in patients with IBS, but the role of EGC in endometriosis has yet to be elucidated. We hypothesized that endometriosis will induce reactive gliosis, with increased expression of the glial fibrillary acidic protein (GFAP) and S100B, in the myenteric plexus of colonic sections in an animal model of endometriosis. METHODS: In the present study animal experiments were employed to explore the impact of endometriosis on the gastrointestinal tract. Using a surgically induced endometriosis rat model, we collected ileal and colonic segments for analysis. We used H&E to assess microscopic damage in colon and ileum, immunofluorescence to measure GFAP and S100B expression in the colon, and toluidine blue staining to measure mast cell infiltration in colon and ileum. Immunofluorescence images were captured using confocal microscope and analyzed using ImageJ software. RESULTS: All endometriosis animals developed vesicles. These animals had a significant increase in the colonic macroscopic damage compared to Sham and Naïve controls. Colonic and ileal sections didn't show statistical differences in microscopic damage between groups, yet endometriosis ileum had significantly increased mast cell infiltration compared to Naïve. GFAP immunostaining showed significantly increased integrated density in endometriosis when compared to Sham or Naïve, while no statistical difference was found in S100B integrated density between groups. CONCLUSIONS: We conclude that endometriosis can alter GI homeostasis by inducing colon inflammation, reactive gliosis, and ileal mast cell infiltration. Taken together this suggests endometriosis can mimic IBS histopathology beyond the symptomatology, reinforcing this disease's complexity and the need to treat it beyond the gynecological setting.

Peroxisome Proliferator-Activated Receptor Alpha Stimulation Preserves Renal Tight Junction Components in a Rat Model of Early-Stage Diabetic Nephropathy.

Chronic hyperglycemia results in morphological and functional alterations of the kidney and microvascular damage, leading to diabetic nephropathy (DN). Since DN progresses to irreversible renal damage, it is important to elucidate a pharmacological strategy aimed for treating DN in the early stage. Here, we used the type 2 diabetic rat model to induce DN and show a nephroprotective effect following the stimulation of PPAR-α, which stabilized renal tight junction components claudin-2, claudin-5, and claudin-16. At 14 weeks old, streptozotocin-induced DN, evidenced by elevated creatinine clearance, proteinuria, and electrolyte excretion, was followed by an elevation in oxidative stress and increasing MMP activities affecting the integrity of claudin-2 and claudin-5. Treatment with a PPAR-α agonists decreased glucose levels in diabetic rats. In addition, we found that the expressions of CLDN-5 in glomeruli, CLDN-2 in proximal tubules, and CLDN-16 in the thick ascending limb of the loop of Henle were increased after treatment. As a result, renal function improved, while the oxidative stress and enzymatic activity of MMP-2 and MMP-9 decreased. In conclusion, PPAR-α stimulation prevented the decrease in claudins through a mechanism involving a correction of hyperglycemia, decreasing it in kidney oxidative stress and MMP-2 and MMP-9 activities, showing a promising nephroprotective action in the early stage of DN.

Gyosaponin ameliorates sevoflurane anesthesia-induced cognitive dysfunction and neuronal apoptosis in rats through modulation of the PI3K/AKT/mTOR pathway.

BACKGROUND: Sevoflurane (Sev) is an inhalational anesthetic for surgical procedures where it can trigger cognitive dysfunction and neuronal apoptosis. Gyosaponin (GpS) was studied for its effects on brain morphology and cognitive behaviors in Sev-anesthetized rats. METHODS: Male Sprague-Dawley rats were induced by 3 % Sev anesthesia, and 25 mg/kg and 100 mg/kg GpS were injected into the rats by tail vein. The in vitro model of Sev anesthesia was constructed by treating primary rat hippocampal neurons with 4.1 % Sev in the presence of GpS (5, 10, and 20 µM). The neuroprotective effects of GpS against Sev-induced cognitive deficits in rats were evaluated using the open field and Morris water maze tests. The apoptosis of hippocampal neurons was observed using HE staining and TUNEL assay. Apoptosis-related proteins and proteins related to the PI3K/Akt/mTOR pathway were determined via Western blot. Also, pro-inflammatory factors were measured via ELISA. RESULTS: GpS diminished the Sev-triggered apoptosis in neurons and Cleaved caspase-3, BAX, TNF-α, IL-6, lessened oxidative stress damage, and stimulated the PI3K/Akt/mTOR pathway. GpS therapy markedly enhanced learning and memory abilities in rats suffering from Sev-related cognitive impairments. CONCLUSION: GpS ameliorates Sev-induced neurotoxicity and cognitive dysfunction by modulating the PI3K/Akt/mTOR pathway and alleviating neuronal apoptosis and oxidative stress.

Effects of paclitaxel and methotrexate associated with cholesterol-rich nanoemulsions on ischemia-reperfusion injury after unilateral lung transplantation in rats.

Currently, the barrier to successful lung transplantation is ischemia and reperfusion injury, which can lead to the development of bronchiolitis obliterans. Paclitaxel and methotrexate are drugs known to inhibit cell proliferation and have anti-inflammatory effects, and the association of these drugs with cholesterol-rich nanoparticles has been shown to be beneficial in the treatment of other transplanted organs. Thirty-three male Sprague Dawley rats were divided into 3 groups: Basal group, no intervention; Control group, received only nanoparticles; Drug group, paclitaxel and methotrexate treatment. Donors and recipients were treated with nanoparticle-paclitaxel and nanoparticle-methotrexate, respectively, 24 h before surgery. The donor lungs from the Drug group were perfused with a preservation solution supplemented with nanoparticles-paclitaxel. After 12 h, the left lung was implanted and reperfused for 1 h. Recipients had an increase in erythrocytes, neutrophils and hemoglobin and a decrease in lymphocytes, and an increase in oxygenation and lactate and a decrease in carbon dioxide. These animals showed an increase in urea and creatinine. The grafts showed perivascular edema and hemorrhage, as well as elevated values of airway resistance, tissue resistance and tissue elastance under mechanical ventilation. The tested drugs were not effective in attenuating the effects of ischemia and reperfusion injury.

Esculetin attenuates cerebral ischemia-reperfusion injury and protects neurons through Nrf2 activation in rats.

Nuclear factor erythroid 2 (NF-E2)-related factor 2 (Nrf2) is a key transcription factor in the antioxidant response and is associated with various chronic diseases. The aim of this study was to explore the action of esculetin, a natural dihydroxy coumarin, on attenuating middle cerebral artery occlusion (MCAO) and reperfusion, and whether its effect is dependent on Nrf2 activation, as well as nuclear factor-kappa B (NF-κB) inhibition. Two doses of esculetin (20 and 40 mg/kg) were tested on rats with MCAO reperfusion. Neurological deficiency, oxidative stress, and pathological analyses were performed to evaluate its effect. An in vitro analysis was also used to confirm whether its action was dependent on the Nrf2/HO-1/NQO-1 pathway. Compared with MCAO reperfusion rats, esculetin improved infarct volume and increased normal-shaped neuron cells by decreasing tumor necrosis factor-alpha (TNF-α), interleukin (IL)-6, and IL-1ß levels. The oxidative stress parameter malondialdehyde (MDA) decreased and the activity of superoxide dismutase (SOD) and glutathione/glutathione disulfide (GSH/GSSG) ratio increased after esculetin treatment. Moreover, esculetin inhibited NF-κB activation induced by MCAO. In vitro, hypoxia/reoxygenation (H/R) impaired the viability of rat neuron cells and esculetin showed a neuron protection effect on cells. Nrf2 inhibitor Brusatol inhibited the activation of Nrf2, heme oxygenase-1 (HO-1), and NAD(P)H quinone oxidoreductase 1 (NQO-1) caused by esculetin and abolished its protection effect. Esculetin protected cerebral neurons from ischemia-reperfusion injury by inhibiting NF-κB and Nrf2/HO-1/NQO-1 activation.

The role of astrocytes in depression, its prevention, and treatment by targeting astroglial gliotransmitter release.

The role of ventral hippocampus (vHipp) astroglial gliotransmission in depression was studied using chronic restraint stress (CRS) and chronic unpredictable mild stress (CUMS) rodent models. CRS increased Cx43 hemichannel activity and extracellular glutamate levels in the vHipp and blocking astroglial Cx43 hemichannel-dependent gliotransmission during CRS prevented the development of depression and glutamate buildup. Moreover, the acute blockade of Cx43 hemichannels induced antidepressant effects in rats previously subjected to CRS or CUMS. This antidepressant effect was prevented by coinjection of glutamate and D-serine. Furthermore, Cx43 hemichannel blockade decreased postsynaptic NMDAR currents in vHipp slices in a glutamate and D-serine-dependent manner. Notably, chronic microinfusion of glutamate and D-serine, L-serine, or the NMDAR agonist NMDA, into the vHipp induced depressive-like symptoms in nonstressed rats. We also identified a small molecule, cacotheline, which blocks Cx43 hemichannels and its systemic administration induced rapid antidepressant effects, preventing stress-induced increases in astroglial Cx43 hemichannel activity and extracellular glutamate in the vHipp, without sedative or locomotor side effects. In conclusion, chronic stress increases Cx43 hemichannel-dependent release of glutamate and D-/L-serine from astrocytes in the vHipp, overactivating postsynaptic NMDARs and triggering depressive-like symptoms. This study highlights the critical role of astroglial gliotransmitter release in chronic stress-induced depression and suggests it can be used as a target for the prevention and treatment of depression.

Expression of NGF, proNGF, p75NTR in lung injury induced by cerebral ischemia-reperfusion in young and elderly rats.

OBJECTIVE: This study aims to investigate the expression levels of Nerve Growth Factor (NGF), the precursor form of NGF (proNGF), and p75 neurotrophin receptor (p75NTR) in lung injury induced by cerebral Ischemia-Reperfusion (I/R) in both young and elderly rats. METHODS: Male Sprague-Dawley rats, categorized as young (3-months-old) and elderly (16-months-old), were divided into four experimental groups: Young Sham, Young I/R, Elderly Sham, and Elderly I/R. Each group underwent either sham surgery or ischemia-reperfusion treatment. Following 24 h post-procedure, the severity of cerebral ischemia was assessed using the Zea Longa 5-point scoring system, and lung tissue pathological changes were examined using Hematoxylin and Eosin (HE) staining. Western blot analysis was utilized to measure the expression levels of NGF, proNGF, and p75NTR proteins in lung tissue. RESULTS: Both young and elderly I/R groups exhibited lung tissue congestion and edema compared to their respective sham groups, with a significant increase in pathological scores (p < 0.05). Furthermore, the elderly I/R group demonstrated a significantly higher pathological score compared to the young I/R group (p < 0.05). Western blot analysis revealed that compared to the young sham group, the expression of NGF in the lung tissue of elderly sham rats decreased (p < 0.05), while proNGF and p75NTR increased (p < 0.05). Additionally, compared to the sham group, the levels of NGF, proNGF, and p75NTR in lung tissue were elevated in both young and elderly I/R groups of rats (p < 0.05). Moreover, the expression of proNGF and p75NTR in lung tissue was higher in the elderly I/R group than in the young I/R group (p < 0.05). CONCLUSION: Cerebral ischemia-reperfusion-induced lung injury was associated with increased expression of proNGF and p75NTR, as well as decreased NGF expression in lung tissue. These alterations in NGF, proNGF, and p75NTR may contribute to the susceptibility to age-related lung injury.

Novel apocynin regulates TRPV1 activity in the trigeminal system and controls pain in a temporomandibular joint neurogenic model.

OBJECTIVE: Herein, we investigate the potential analgesic effect of a newly synthesized chalcone-derived apocynin in a neurogenic pain model. METHODS: Molecular docking was used to foretell the apocynin binding features and dynamics with the TRPV1 channel, and the activity was tested in vitro, using transfected HEK 293T cells with the rat TRPV1 receptor. The analgesic effect of apocynin was investigated using a capsaicin-induced pain model. The expression of TRPV1, TRPA1, TRPM8, and MAPKs was assessed by electrophoresis, and immunosorbent assays were performed to quantify the neurotransmitters Substance P, Glutamate, and CGRP. A survival assay using Galleria mellonella was carried out to determine the toxicity. RESULTS: We observed that apocynin exhibits greater thermodynamic stability. Upon apocynin ligand binding, it changes the electrostatic potential for a predominantly electronegative state in the interior and neutral in its external vanilloid pocket. Treatment of apocynin induces antinociceptive effects against the noxious challenge of capsaicin. Histologically, apocynin decreased the number of TRPV1+ immunopositive cells. Electrophoresis showed reduced phosphorylation of p44/42 (ERK1/2) and decreased protein levels of substance P, and CGRP. In the survival assay, apocynin showed low toxicity. CONCLUSIONS: In conclusion, we provide proof-of-principles that the newly synthesized apocynin compound effectively prevented nociception in a neurogenic model of orofacial pain.

Effect of chronic exogenous oxytocin administration on exercise performance and cardiovagal control in hypobaric hypoxia in rats.

BACKGROUND: Outstanding exercise performance has been associated with an exacerbated vagal outflow. Nevertheless, during high-altitude hypobaric-hypoxia (HH), there is a baroreflex-dependent parasympathetic withdrawal and exercise performance deterioration. Notably, vagal control is pivotal in exercise performance, and exogenous oxytocin (OXY) administration has been shown to enhance parasympathetic drive; however, no evidence shows their role in exercise performance during HH. Then, this study aimed to examine the effect of prolonged exogenous oxytocin (OXY) administration on exercise performance during hypobaric hypoxia (HH) in rats. RESULTS: A vehicle group (n = 6) and an OXY group (n = 6) performed incremental exercise and baroreflex tests during both normobaric normoxia (NN) and HH (PO2: 100 mmHg, simulated 3,500 m) prior (pre-) and after (post-) 14 days of administration. The results showed that at pre-, there were no significant differences in exercise performance between the two groups, while at post-, the OXY group exhibited similar performance between NN and HH, while the Vehicle group maintained a significant decline in performance at HH compared to NN. At post-, the Vehicle group also demonstrated a reset in the baroreflex and a worse bradycardic response in HH, which was reversed in the OXY group, while the hypoxic ventilatory response was similar in both groups. CONCLUSION: The findings suggest prolonged OXY administration prevents impaired exercise performance and vagal control during short-term HH.

GLUT1 and prorenin receptor mediate differential regulation of TGF-ß and CTGF in renal inner medullary collecting duct cells during high glucose conditions.

BACKGROUND: During diabetes, prorenin is highly produced by the renal collecting ducts. The binding of prorenin to (pro)renin receptor (PRR) on the apical plasma membrane triggers intracellular profibrotic genes, including TGF-ß and CTGF. However, the underlying mechanisms contributing to the stimulation of these pathways remain unclear. Hence, we hypothesize that the glucose transporter-1 (GLUT1) favors the PRR-dependent stimulation of TGF-ß and CTGF in the distal nephron segments during high glucose (HG) conditions. METHODS: To test this hypothesis, primary cultured renal inner medullary collecting duct (IMCD) cells were treated with normal glucose (NG, 5 mM) or high glucose (HG, 25 mM) for 48 h in the presence or absence of the GLUT1-specific inhibitor BAY 876 (2 nM). Additionally, IMCD cells were treated with the PRR antagonist PRO20. The expression of TGF-ß and CTGF was quantified by immunoblot and qRT-PCR. RESULTS: HG increased GLUT1 mRNA and protein abundance, while BAY 876 inhibited these responses. HG treatment upregulated PRR, but the concomitant treatment with BAY 876 partially prevented this effect. TGF-ß and CTGF expressions were augmented in IMCD cells treated with HG. However, PRO20 prevented the increases in TGF-ß but not those of CTGF. GLUT1 inhibition partially prevented the increases in reactive oxygen species (ROS) during HG while PRO20 did not. ROS scavenging impaired CTGF upregulation during HG conditions. Additionally, long-term exposure to HG increases lipid peroxidation and reduced cell viability. CONCLUSIONS: The data indicate that glucose transportation via GLUT1 is implicated in the PRR-dependent upregulation of TGF-ß while CTGF is mediated mainly via a mechanism depending on ROS formation in renal medullary collecting duct cells.

S-(+)-mecamylamine increases the firing rate of serotonin neurons and diminishes depressive-like behaviors in an animal model of stress.

Mecamylamine, a noncompetitive blocker of nicotinic acetylcholine receptors (nAChRs), is the racemic mixture of two stereoisomers: S-(+)-mecamylamine (S-mec) and R-(-)-mecamylamine (R-mec), with distinct interactions with α4ß2 nAChRs. It has been shown that mecamylamine increases glutamate release and excites serotonergic (5-HT) neurons in the dorsal raphe nucleus (DRN). In this study, we separately evaluated the effects of S-mec and R-mec on 5-HT neuron excitability. S-mec (3 µM) increased firing frequency by 40 %, while R-mec (3 µM) raised it by only 22 %. S-mec acts as a positive allosteric modulator on high-sensitivity (HS) α4ß2 nAChRs at glutamate terminals, enhancing spontaneous excitatory postsynaptic currents (sEPSCs) in 5-HT neurons. Conversely, R-mec decreased sEPSCs by blocking HS α4ß2 nAChRs and reduced GABA-mediated inhibitory currents (sIPSCs) by blocking α7 nAChRs at GABAergic terminals. These mechanisms make S-mec more effective than R-mec in enhancing 5-HT neuron firing. Moreover, combining S-mec with TC-2559, a selective agonist of HS α4ß2 nAChRs, increased firing frequency by 65 %, exceeding the effect of S-mec alone. To validate these findings, we evaluated the antidepressant effects of S-mec (1 mg/kg) combined with TC-2559 or RJR-2403, another α4ß2 nAChR agonist. This combination successfully reduced depression-like behaviors, suggesting a potential treatment strategy for patients resistant to conventional antidepressants.

Estrogen receptor α regulates the IKKs/NF-kB activity involved in the development of mechanical allodynia induced by REM sleep deprivation in rats.

Several signaling pathways that converge in NF-kB activation have been linked to developing and maintaining different types of pathological pain. In addition, some mechanisms implied in the establishment of chronic pain have been demonstrated to have a sex-dependent correlation. This study aimed to determine if the IKKs/NF-kB signaling pathway is involved in establishing REM sleep deprivation (REMSD) induced mechanical allodynia in rats and its possible regulation depending on estradiol and estrogen receptors. Intrathecal administration of BMS-345541 or minocycline, two drugs that reduce the IKKs/NF-kB activity, avoided the development of mechanical allodynia in female but not in male rats subjected to 48 h of REMSD. Ovariectomy in female rats abolished the effect of BMS-345541 and minocycline. Meanwhile, the 17-ß-estradiol restitution restored it. Intrathecal administration of MPP, a selective ERα antagonist, but not PHTPP, a selective ERß antagonist, avoided the effect of BMS-345541 in female rats without hormonal manipulation. In addition, the transient run-down of ERα in female rats abolished the effect of BMS-345541. All data suggest an important role of ERα as a regulator of the IKKs/NF-kB activity. REMSD increased the ERα protein expression in the dorsal root ganglia and the dorsal spinal cord in females but not in male rats. Interestingly, ERα activation or ERα overexpression allowed the effect of BMS-345541 in male rats. Data suggest an important regulatory role of ERα in the IKKs/NF-kB activity on establishing mechanical allodynia induced by REMSD in female rats.

Enhancing osteoblast differentiation and bone repair: The priming effect of photobiomodulation on adipose stromal cells.

Cellular therapy using adipose tissue-derived mesenchymal stromal cells (at-MSCs) has garnered attention for the treatment of bone defects. Therefore, preconditioning strategies to enhance the osteogenic potential of at-MSCs could optimize cell therapy outcomes, and photobiomodulation (PBM) therapy has emerged as an effective, noninvasive, and low-cost alternative. This study explored the impacts of PBM on at-MSCs differentiation and the subsequent repair of bone defects treated with cell injection. Rat at-MSCs were cultured and irradiated (at-MSCsPBM) following the PBM protocol (660 nm; 20 mW; 0.714 W/cm2; 0.14 J; 5 J/cm2). Cellular differentiation was assessed based on the expression of gene and protein markers. Reactive oxygen species (ROS) were detected using fluorescence. At-MSCsPBM were injected into 5-mm calvarial lesions, and bone formation was analyzed using micro-CT and histological evaluations. At-MSCs were used as control. Data were analyzed using the ANOVA or t-test. At-MSCsPBM exhibited high levels of gene and protein runt-related transcription factor-2 (Runx2) and alkaline phosphatase (Alp) expression. PBM increased ALP activity and significantly reduced ROS levels. In addition, PBM increased the expression of Wnt pathway-associated genes. In vivo, there was an increase in the morphometric parameters, including bone volume, percentage of bone volume, bone surface area, and trabecular number, in at-MSCsPBM-treated defects compared with those in the control. These findings suggest that PBM enhances the osteogenic potential of at-MSCs, thereby supporting the advancement of improved cellular therapies for bone regeneration.