Metabolomics Analysis of Sodium Salicylate Improving the Preservation Quality of Ram Sperm

The aim of this study was to investigate the effects of sodium salicylate (SS) on the preservation and metabolic regulation of sheep sperm. Under 4 °C low-temperature conditions, SS (at 10 µM, 20 µM, 30 µM, and 50 µM) was added to the semen diluent to detect sperm motility, plasma membrane, and acrosome integrity. Based on the selected optimal concentration of SS (20 µM), the effects of 20 µM of SS on sperms' antioxidant capacity and mitochondrial membrane potential (MMP) were evaluated, and metabolomics analysis was conducted. The results showed that on the 20th day of low-temperature storage, the sperm motility of the 20 µM SS group was 62.80%, and the activities of catalase (CAT) and superoxide dismutase (SOD) were significantly higher than those of the control group (p < 0.01). The content of Ca2+, reactive oxygen species (ROS), and malondialdehyde (MDA) were significantly lower than those of the control group (p < 0.01), and the total antioxidant capacity (T-AOC) was significantly higher than that of the control group (p < 0.05); mitochondrial activity and the total cholesterol (TC) content were significantly higher than those in the control group (p < 0.01). An ultrastructural examination showed that in the SS group, the sperm plasma membrane and acrosome were intact, the fibrous sheath and axoneme morphology of the outer dense fibers were normal, and the mitochondria were arranged neatly. In the control group, there was significant swelling of the sperm plasma membrane, rupture of the acrosome, and vacuolization of mitochondria. Using metabolomics analysis, 20 of the most significant differential metabolic markers were screened, mainly involving 6 metabolic pathways, with the amino acid biosynthesis pathway being the most abundant. In summary, 20 µM of SS significantly improved the preservation quality of sheep sperm under low-temperature conditions of 4 °C.

Electrophysiological and molecular changes following neuroprotective placental protein administration on tinnitus-induced rats

Objective

Despite 6%-20% of the adult population suffering from tinnitus, there is no standard treatment for it. Placenta extract has been used for various therapeutic purposes, including hearing loss. Here, we evaluate the effect of a novel neuroprotective protein composition (NPPC) extract on electrophysiological and molecular changes in the medial geniculate body (MGB) of tinnitus-induced rats.

Methods

To evaluate the protein analysis by western blot, the rats were divided into three groups: (1) saline group (intraperitoneal injection of 200 mg/kg saline twice a day for 28 consecutive days, (2) chronic Na-Sal group received sodium salicylate as in the first group, and (3) chronic treatment group (received salicylate 200 mg/kg twice daily for 2 weeks, followed by 0.4 mg NPPC daily from day 14 to day 28). Single-unit recordings were performed on a separate group that was treated as in group 4. Gap-prepulse inhibition of the acoustic startle (GPIAS) and pre-pulse inhibition (PPI) was performed to confirm tinnitus in all groups at the baseline, 14th and 28th days.

Results

Western blot analysis showed that the expression of γ-Aminobutyric acid Aα1 subunit (GABA Aα1), N-methyl-d-aspartate receptor subtype 2B (NR2B or NMDAR2B), α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptors subunit GluR1 (GluR1), and α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptors subunit GluR2 (GluR2) decreased after Na-Sal injection, while NPPC upregulated their expression. MGB units in rats with tinnitus showed decreased spontaneous firing rate, burst per minute, and a spike in a burst. After NPPC administration, neural activity patterns showed a significant positive effect of NPPC on tinnitus.

Conclusion

NPPC can play an effective role in the treatment of tinnitus in salicylate-induced rats, and MGB is one of the brain areas involved in these processes.

Level of Evidence

NA.

Targeting Pseudomonas aeruginosa quorum sensing with sodium salicylate modulates immune responses in vitro and in vivo

Introduction

Chronic infections are a major clinical challenge in hard-to-heal wounds and implanted devices. Pseudomonas aeruginosa is a common causative pathogen that produces numerous virulence factors. Due to the increasing problem of antibiotic resistance, new alternative treatment strategies are needed. Quorum sensing (QS) is a bacterial communication system that regulates virulence and dampens inflammation, promoting bacterial survival. QS inhibition is a potent strategy to reduce bacterial virulence and alleviate the negative impact on host immune response.

Aim

This study investigates how secreted factors from P. aeruginosa PAO1, cultured in the presence or absence of the QS inhibitor sodium salicylate (NaSa), influence host immune response.

Material and methods

In vitro, THP-1 macrophages and neutrophil-like HL-60 cells were used. In vivo, discs of titanium were implanted in a subcutaneous rat model with local administration of P. aeruginosa culture supernatants. The host immune response to virulence factors contained in culture supernatants (+/-NaSa) was characterized through cell viability, migration, phagocytosis, gene expression, cytokine secretion, and histology.

Results

In vitro, P. aeruginosa supernatants from NaSa-containing cultures significantly increased THP-1 phagocytosis and HL-60 cell migration compared with untreated supernatants (-NaSa). Stimulation with NaSa-treated supernatants in vivo resulted in: (i) significantly increased immune cell infiltration and cell attachment to titanium discs; (ii) increased gene expression of IL-8, IL-10, ARG1, and iNOS, and (iii) increased GRO-α protein secretion and decreased IL-1β, IL-6, and IL-1α secretion, as compared with untreated supernatants.

Conclusion

In conclusion, treating P. aeruginosa with NaSa reduces the production of virulence factors and modulates major immune events, such as promoting phagocytosis and cell migration, and decreasing the secretion of several pro-inflammatory cytokines.

Interactions of Sodium Salicylate with β-Cyclodextrin and an Anionic Resorcin[4]arene: Mutual Diffusion Coefficients and Computational Study

The interaction between sodium salicylate (NaSal) and the two macrocycles 5,11,17,23-tetrakissulfonatomethylene-2,8,14,20-tetra(ethyl)resorcinarene (Na₄EtRA) and β-cyclodextrin (β-CD) has been studied by the determination of ternary mutual diffusion coefficients, and spectroscopic and computational techniques. The results obtained by the Job method suggest that the complex formation is given in a 1:1 ratio for all systems. The mutual diffusion coefficients and the computational experiments have shown that the β-CD-NaSal system presents an inclusion process, whereas the Na₄EtRA-NaSal system forms an outer-side complex. This fact is also in line with the results obtained from the computational experiments, where the calculated solvation free energy has been found to be more negative for the Na₄EtRA-NaSal complex because of the partial entry of the drug inside the Na₄EtRA cavity.

Low-Dose Sodium Salicylate Promotes Ovulation by Regulating Steroids via CYP17A1

To meet the current demand of assisted reproduction and animal breeding via superovulation and reduce the impact of hormone drugs, it is necessary to develop new superovulation drugs. This study examined the role of inflammation and steroids in ovulation. Sodium salicylate can regulate inflammation and steroids. However, the effect of sodium salicylate on ovulation has not been studied. In this study, mice were intraperitoneally injected with different concentrations of sodium salicylate for four consecutive days. The effects of sodium salicylate on oocyte quality and on the number of ovulations were examined, and these effects were compared with those of pregnant horse serum gonadotropin (PMSG)/follicle-stimulating hormone (FSH) treatment. We found that low-dose sodium salicylate increased the levels of ovulation hormones and inflammation by promoting the expression of CYP17A1. Sodium salicylate had the same effect as the commonly used superovulation drug PMSG/FSH and reduced the histone methylation level. Sodium salicylate can promote ovulation in mice and Awang sheep. It can greatly decrease the use of hormone drugs, reduce breeding costs and physical impacts, and can thus be used for livestock breeding.

Protective Effect of Curcumin against Sodium Salicylate-Induced Oxidative Kidney Damage, Nuclear Factor-Kappa Dysregulation, and Apoptotic Consequences in Rats

This study examined the effect of sodium salicylates (SS), alone and in combination with curcumin (CUR), on kidney function and architecture in rats. Five rat groups were given 1 mL physiological saline/rat orally, 1 mL olive oil/rat orally, 50 mg CUR/kg bwt orally, 300 mg SS/kg bwt intraperitoneally, or CUR+SS for 15 days. The hematological indices, serum protein profile, serum electrolytes balance, oxidative stress, and lipid peroxidation of kidney tissues were assessed. The histopathological examination and immune expression of Caspase-3 and nuclear factor kappa (NF-κB) were conducted. The findings showed that SS injection induced nephrotoxic activity, including increased serum urea, creatinine, and uric acid levels. It also caused apparent pathological alterations with increased Caspase-3 and NF-κB immuno-expression. In addition, thrombocytopenia, leukocytosis, neutrophilia, hyponatremia, hypochloremia, hypocalcemia, and hypomagnesemia but not hyperkalemia and hyperphosphatemia were evident in SS-injected rats. Moreover, SS exposure increased serum α1 globulin, renal tissue malondialdehyde, and Caspase-3 levels but superoxide dismutase, glutathione peroxidase, and Bcl-2 levels declined. Meanwhile, CUR significantly counteracted the SS harmful impacts on kidneys but SS+CUR co-administration induced an anemic condition. Overall, CUR has an evident protective role against SS-induced renal damage, but the disturbed hematological alterations should be carefully taken into consideration in their combined use.

Ablation of TRPV1 Abolishes Salicylate-Induced Sympathetic Activity Suppression and Exacerbates Salicylate-Induced Renal Dysfunction in Diet-Induced Obesity

Sodium salicylate (SA), a cyclooxygenase inhibitor, has been shown to increase insulin sensitivity and to suppress inflammation in obese patients and animal models. Transient receptor potential vanilloid 1 (TRPV1) is a nonselective cation channel expressed in afferent nerve fibers. Cyclooxygenase-derived prostaglandins are involved in the activation and sensitization of TRPV1. This study tested whether the metabolic and renal effects of SA were mediated by the TRPV1 channel. Wild-type (WT) and TRPV1-/- mice were fed a Western diet (WD) for 4 months and received SA infusion (120mg/kg/day) or vehicle for the last 4 weeks of WD feeding. SA treatment significantly increased blood pressure in WD-fed TRPV1-/- mice (p < 0.05) but not in WD-fed WT mice. Similarly, SA impaired renal blood flow in TRPV1-/- mice (p < 0.05) but not in WT mice. SA improved insulin and glucose tolerance in both WT and TRPV1-/- mice on WD (all p < 0.05). In addition, SA reduced renal p65 and urinary prostaglandin E2, prostaglandin F1α, and interleukin-6 in both WT and TRPV1-/- mice (all p < 0.05). SA decreased urine noradrenaline levels, increased afferent renal nerve activity, and improved baroreflex sensitivity in WT mice (all p < 0.05) but not in TRPV1-/- mice. Importantly, SA increased serum creatinine and urine kidney injury molecule-1 levels and decreased the glomerular filtration rate in obese WT mice (all p < 0.05), and these detrimental effects were significantly exacerbated in obese TRPV1-/- mice (all p < 0.05). Lastly, SA treatment increased urine albumin levels in TRPV1-/- mice (p < 0.05) but not in WT mice. Taken together, SA-elicited metabolic benefits and anti-inflammatory effects are independent of TRPV1, while SA-induced sympathetic suppression is dependent on TRPV1 channels. SA-induced renal dysfunction is dependent on intact TRPV1 channels. These findings suggest that SA needs to be cautiously used in patients with obesity or diabetes, as SA-induced renal dysfunction may be exacerbated due to impaired TRPV1 in obese and diabetic patients.

Sodium salicylate enhances neural excitation via reducing GABAergic transmission in the dentate gyrus area of rat hippocampus in vivo

Sodium salicylate, one of the non-steroidal anti-inflammatory drugs, is widely prescribed in the clinic, but a high dose of usage can cause hyperactivity in the central nervous system, including the hippocampus. At present, the neural mechanism underlying the induced hyperactivity is not fully understood, in particular, in the hippocampus under an in vivo condition. In this study, we found that systemic administration of sodium salicylate increased the field excitatory postsynaptic potential slope and the population spike amplitude in a dose-dependent manner in the hippocampal dentate gyrus area of rats with in vivo field potential extracellular recordings, which indicates that sodium salicylate enhances basal synaptic transmission and neural excitation. In the presence of picrotoxin, a GABA-A receptor antagonist, sodium salicylate failed to increase the initial slope of the field excitatory postsynaptic potential and the amplitude of the population spike in vivo. To further explore how sodium salicylate enhances the neural excitation, we made whole-cell patch-clamp recordings from hippocampal slices. We found that perfusion of the slice with sodium salicylate decreased electrically evoked GABA receptor-mediated currents, increased paired-pulse ratio, and lowered frequency and amplitude of miniature inhibitory postsynaptic currents. Together, these results demonstrate that sodium salicylate enhances the neural excitation through suppressing GABAergic synaptic transmission in presynaptic and postsynaptic mechanisms in the hippocampal dentate gyrus area. Our findings may help understand the side effects caused by sodium salicylate in the central nervous system.

Sodium Salicylate Influences the Pseudomonas aeruginosa Biofilm Structure and Susceptibility Towards Silver

Hard-to-heal wounds are typically infected with biofilm-producing microorganisms, such as Pseudomonas aeruginosa, which strongly contribute to delayed healing. Due to the global challenge of antimicrobial resistance, alternative treatment strategies are needed. Here, we investigated whether inhibition of quorum sensing (QS) by sodium salicylate in different P. aeruginosa strains (QS-competent, QS-mutant, and chronic wound strains) influences biofilm formation and tolerance to silver. Biofilm formation was evaluated in simulated serum-containing wound fluid in the presence or absence of sodium salicylate (NaSa). Biofilms were established using a 3D collagen-based biofilm model, collagen coated glass, and the Calgary biofilm device. Furthermore, the susceptibility of 48-h-old biofilms formed by laboratory and clinical strains in the presence or absence of NaSa towards silver was evaluated by assessing cell viability. Biofilms formed in the presence of NaSa were more susceptible to silver and contained reduced levels of virulence factors associated with biofilm development than those formed in the absence of NaSa. Biofilm aggregates formed by the wild-type but not the QS mutant strain, were smaller and less heterogenous in size when grown in cultures with NaSa compared to control. These data suggest that NaSa, via a reduction of cell aggregation in biofilms, allows the antiseptic to become more readily available to cells.

Role of the caudate-putamen nucleus in sensory gating in induced tinnitus in rats

Tinnitus can be described as the conscious perception of sound without external stimulation, and it is often accompanied by anxiety, depression, and insomnia. Current clinical treatments for tinnitus are ineffective. Although recent studies have indicated that the caudate-putamen nucleus may be a sensory gating area involved in noise elimination in tinnitus, the underlying mechanisms of this disorder are yet to be determined. To investigate the potential role of the caudate-putamen nucleus in experimentally induced tinnitus, we created a rat model of tinnitus induced by intraperitoneal administration of 350 mg/kg sodium salicylate. Our results revealed that the mean spontaneous firing rate of the caudate-putamen nucleus was increased by sodium salicylate treatment, while dopamine levels were decreased. In addition, electrical stimulation of the caudate-putamen nucleus markedly reduced the spontaneous firing rate of neurons in the primary auditory cortex. These findings suggest that the caudate-putamen nucleus plays a sensory gating role in sodium salicylate-induced tinnitus. This study was approved by the Institutional Animal Care and Use Committee of Peking University Health Science Center (approval No. A2010031) on December 6, 2017.

Sodium salicylate interferes with quorum-sensing-regulated virulence in chronic wound isolates of Pseudomonas aeruginosa in simulated wound fluid

Introduction. An important factor for delayed healing of chronic wounds is the presence of bacteria. Quorum sensing (QS), a cell density-dependent signalling system, controls the production of many virulence factors and biofilm formation in Pseudomonas aeruginosa.Aim. Inhibition by sodium salicylate (NaSa) of QS-regulated virulence expression was evaluated in QS-characterized clinical wound isolates of P. aeruginosa, cultured in serum-containing medium.Methodology. Fourteen clinical P. aeruginosa strains from chronic wounds were evaluated for the production of QS signals and virulence factors. Inhibition of QS by NaSa in P. aeruginosa clinical strains, wild-type PAO1 and QS reporter strains was evaluated using in vitro assays for the production of biofilm, pyocyanin, siderophores, alkaline protease, elastase and stapholytic protease.Results. Six clinical strains secreted several QS-associated virulence factors and signal molecules and two were negative for all factors. Sub-inhibitory concentrations of NaSa downregulated the expression of the QS-related genes lasB, rhlA and pqsA and reduced the secretion of several virulence factors in PAO1 and clinical strains cultured in serum. Compared to serum-free media, the presence of serum increased the expression of QS genes and production of siderophores and pyocyanin but decreased biofilm formation.Conclusions. Pseudomonas aeruginosa from chronic wound infections showed different virulence properties. While very few strains showed no QS activity, approximately half were highly virulent and produced QS signals, suggesting that the targeting of QS is a viable and relevant strategy for infection control. NaSa showed activity as a QS-inhibitor by lowering the virulence phenotypes and QS signals at both transcriptional and extracellular levels.

Induction of a thoracolumbar supernumerary rib in rat developmental toxicity studies: A short discussion on the critical window

Thoracolumbar supernumerary ribs (TSRs) are classified as less severe skeletal anomalies in rat developmental toxicity studies, although their incidence is relatively high in rodent studies. To investigate the characteristics of the critical window for chemically-induced TSR, in this study, rats were administered 5-fluorocytocine (5-FC) or sodium salicylate (SAL) at one of three time periods on gestational day (GD) 9, early morning (7:00 am), midday (12:00 pm to 1:00 pm), or late afternoon (4:00 pm or 7:00 pm). The incidence of TSR and other anomalies were assessed in GD20 fetuses. A single treatment with both chemicals on GD9-induced TSR, with the incidence highest when administered at 7:00 Am, decreasing gradually when administered later. This trajectory was clearer in rats treated with 5-FC than with SAL. The critical period of TSR induction is shorter in rats administered 5-FC than SAL. The characteristics of the critical window may cause variability in the incidence of TSR observed in developmental toxicity studies.

Sustained-Release Injectable Hydrogel Formulations for Administration of Sodium Salicylate in Broiler Chickens

We developed injectable hydrogels for the slow release of analgesic drugs in birds as an in vivo model of pharmacokinetics in wild avian species. Hydrogels loaded with sodium salicylate (NaSA) were injected subcutaneously in Ross broiler chickens. The hydrogels were made by dissolving sodium alginate and NaSA in water at 2 different concentrations (low, LALG; high, HALG) and then adding calcium chloride. In vitro drug release studies were performed by swelling the hydrogels in water and analyzing serial samples by ultraviolet-visible (UV-Vis) spectroscopy. Dried hydrogel films of the same formulations of the two alginate concentrations then were dissolved in sterile water for the in vivo pharmacokinetic study conducted in 18 chickens divided into 3 groups of 6 birds. Each of the 2 resultant NaSA hydrogel solutions were filtered with 0.2-µm syringe filters before injecting at a NaSA dose of 150 mg/kg SC in the respective LALG or HALG groups. The control group was injected SC with the same dose of NaSA dissolved in water. Pharmacokinetics parameters calculated by the compartmental and noncompartmental approaches were compared among the 3 groups by the Kruskal-Wallis test. Results of in vitro studies showed that both hydrogels released 80% of the drug during the first 3.5 hours. Results of the pharmacokinetic study indicated that NaSA concentrations remained above the minimum effective concentration (MEC) for analgesia in humans for 24 ± 8.9 (LALG) to 26 ± 4 (HALG) hours for the hydrogel formulations compared to 10 ± 5.6 hours for the aqueous formulation. These hydrogel formulations may have potential in providing long-term analgesia in avian species, but need further evaluation with pharmacodynamic or pharmacokinetic/pharmacodynamic modeling studies.

Testing the Central Gain Model: Loudness Growth Correlates with Central Auditory Gain Enhancement in a Rodent Model of Hyperacusis

The central gain model of hyperacusis proposes that loss of auditory input can result in maladaptive neuronal gain increases in the central auditory system, leading to the over-amplification of sound-evoked activity and excessive loudness perception. Despite the attractiveness of this model, and supporting evidence for it, a critical test of the central gain theory requires that changes in sound-evoked activity be explicitly linked to perceptual alterations of loudness. Here we combined an operant conditioning task that uses a subject's reaction time to auditory stimuli to produce reliable measures of loudness growth with chronic electrophysiological recordings from the auditory cortex and inferior colliculus of awake, behaviorally-phenotyped animals. In this manner, we could directly correlate daily assessments of loudness perception with neurophysiological measures of sound encoding within the same animal. We validated this novel psychophysical-electrophysiological paradigm with a salicylate-induced model of hearing loss and hyperacusis, as high doses of sodium salicylate reliably induce temporary hearing loss, neural hyperactivity, and auditory perceptual disruptions like tinnitus and hyperacusis. Salicylate induced parallel changes to loudness growth and evoked response-intensity functions consistent with temporary hearing loss and hyperacusis. Most importantly, we found that salicylate-mediated changes in loudness growth and sound-evoked activity were correlated within individual animals. These results provide strong support for the central gain model of hyperacusis and demonstrate the utility of using an experimental design that allows for within-subject comparison of behavioral and electrophysiological measures, thereby making inter-subject variability a strength rather than a limitation.

Sodium salicylate alters temporal integration measured through increasing stimulus presentation rates

OBJECTIVE

High doses of sodium salicylate (SS) are known to induce tinnitus, general hyperexcitability in the central auditory system, and to cause mild hearing loss. We used the auditory brainstem response (ABR) to assess the effects of SS on auditory sensitivity and temporal processing in the auditory nerve and brainstem. ABRs were evoked using tone burst stimuli varying in frequency and intensity with presentation rates from 11/s to 81/s.

DESIGN

ABRs were recorded and analysed prior to and after SS treatment in each animal, and peak 1 and peak 4 amplitudes and latencies were determined along with minimal response threshold.

STUDY SAMPLE

Nine young adult CBA/CaJ mice were used in a longitudinal within-subject design.

RESULTS

No measurable effects of presentation rate were found on ABR threshold prior to SS; however, following SS administration increasing stimulus rates lowered ABR thresholds by as much as 10 dB and compressed the peak amplitude by intensity level functions.

CONCLUSIONS

These results suggest that SS alters temporal integration and compressive nonlinearity, and that varying the stimulus rate of the ABR may prove to be a useful diagnostic tool in the study of hearing disorders that involve hyperexcitability.

[The sodium salicylate affects the expression of NMDA receptor and GABAa receptor subunits in spiral ganglion neurons of the cochlea through DA receptor]

Objective:To investigate mRNA expression of dopamine receptor subtypes in the rat cochlear spiral ganglion neurons (SGN) following exposure to the sodium salicylate. In addition, we observed the effect of sodium salicylate on N methyl-D-aspartic acid (NMDA) receptor subunit NR1 and gamma aminobutyric acid (GABA)a receptor subunit GABRα2 mRNA under the circumstance of DR activation or blocking. Moreover, we also focused on the the interaction between receptors mediated by SS.Method:Immunofluorescence techniques were applied to detect DR (DR1 and DR2) expression in cultured rat SGN. Moreover, RT-PCR was performed to assess NR1 and GABRα2 subunit mRNA.Result:Immunofluorescence images showed co-localization of DR1/DR2 and βⅢ-tubulin protein in SGN bodies and axons. RT-PCR results illustrated that ①DR subtypes of DRd1-5 were detected in the SGN. ②The mRNA expression of all subtypes of DR and GABRα2, NR1 subunits were obviously upregulated except DRd3 after treatment with sodium salicylate. Among them, DRd1 expression increased 34.64%(t=-5.123,P=0.007),DRd2 expression increased 34.60%(t=-5.206,P=0.006),DRd4 expression increased 20.87%(t=-3.337,P=0.029),DRd5 expression increased 26.42%(t=-6.054,P=0.004),GABRα2 expression increased 30.41%(t=-2.839,P=0.047),NR1 expression increased 39.22%(t=-6.243,P=0.003).③After exposure to sodium salicylate (5 mmol/L), dopamine (100 μmol/L), DR1 agonist (SKF38393,20 μmol/L), DR2 agonist (Quinpirole,20 μmol/L), GABRα2 expression increased 21.78%,27.45%,33.02%,33.42% respectively (F=12.399,P=0.001),and NR1 expression increased 28.70%,26.82%,29.03%,35.05%(F=50.395,P=0.000) respectively.④Compared with the group of sodium salicylate treatment alone, both sodium salicylate + DR1 antagonist (SCH23390,20 μmol/L) group and sodium salicylate + DR2 antagonists (Eticlopride,20 μmol/L) group had a suppression on GABRα2 and NR1 mRNA expression.GABRα2 mRNA reduced 29.56%,37.10%(F=22.101,P=0.000) and NR1 mRNA expression decreased 37.62%,32.83% respectively(F=72.933,P=0.000).Conclusion:Most of the DR subtypes mRNA expression in SGN were increased following exposure to sodium salicylate. DR may be involved in the effect of sodium salicylate on GABAaR and NMDAR mRNA expression.

Pharmacokinetics of Salicylic Acid Following Intravenous and Oral Administration of Sodium Salicylate in Sheep

Simple Summary

Scarcity of non-steroidal anti-inflammatory drugs (NSAID) to minimise the pain in sheep instigated the current study. The aim of this study was to know the pharmacokinetic parameters of salicylic acid in New Zealand sheep after administration of multiple intravenous and oral doses of sodium salicylate (sodium salt of salicylic acid). Results of the study suggest that the half-life of the drug was shorter and clearance was faster after intravenous administration as compared to that of the oral administration. The minimum effective concentration required to produce analgesia in humans (16.8 µL) was achieved in sheep for about 0.17 h in the current study after intravenous administration of 100 and 200 mg/kg body weight of sodium salicylate. However, oral administration of these doses failed to achieve the minimum effective concentration as mentioned above. This study is of significance as it adds valuable information on pharmacokinetics and its variation due to breed, species, age, gender and environmental conditions. As per the authors’ knowledge, this is the only study showing detailed information about absorption, distribution and elimination of salicylic acid in New Zealand Sheep. An intravenous administration of sodium salicylate at 100 and 200 mg/kg dose may produce analgesia in sheep, which requires further investigation using pharmacokinetic–pharmacodynamic (PKPD) integration or modelling techniques.

Abstract

The pharmacokinetics of salicylic acid (SA) in sheep was evaluated following intravenous (IV) and oral administration of sodium salicylate (sodium salt of salicylic acid) at different doses. Six healthy sheep were administered sodium salicylate (SS) IV at doses of 10, 50, 100 and 200 mg/kg body weight and another six sheep were drenched with 100 and 200 mg/kg of SS orally. Both studies were randomised crossover trials. A one-week washout period between each treatment was allowed in both studies. Blood samples were collected at 0, 15, 30 min and 1, 2, 4 and 6 h after IV and oral SS administrations. Plasma SA concentrations were determined using high-performance liquid chromatography (HPLC) with diode array detection method. Pharmacokinetic variables were calculated in a non-compartmental model. The elimination half-life (T_{1/2 el}) of SA after IV administration of 200 mg/kg SS was 1.16 ± 0.32 h. Mean bioavailability of SA was 64%, and mean T_{1/2 el} was 1.90 ± 0.35 h, after 200 mg/kg of oral SS. The minimum plasma SA concentration (16.8 µg/mL) reported to produce analgesia in humans was achieved after IV administration of 100 and 200 mg/kg SS in sheep for about 0.17 h in this study. Experiments on pharmacokinetic–pharmacodynamics modelling are required to determine the actual effective plasma concentration range of SA in sheep.

DNA methylation of the prestin gene and outer hair cell electromotileresponse of the cochlea in salicylate administration

Background/aim: Activity of the prestin gene may have a role in the pathogenesis of salicylate-induced ototoxicity. We investigated DNA methylation for prestin gene exon 1 in salicylate-injected guinea pigs.Materials and methods: Fifteen guinea pigs (30 ears) underwent audiological evaluation including 1000 Hz probe-tone tympanometry and a distortion product otoacoustic emission (DPOAE) test. The animals were randomly divided into three groups. Groups 2 (8 ears) and 3 (14 ears) were injected with intramuscular saline and sodium salicylate (200 mg/kg), respectively twice daily for 2 weeks. Group 1 (8 ears) received no injection. DPOAE measurements were performed at baseline; after 1, 2, 4, and 8 h (acute effect); and after 1 and 2 weeks (chronic effect). After audiological measurements, the animals were sacrificed for DNA isolation.Results: While a significant decrease (P < 0.01) was found for the acute effect in all frequencies in Group 3 according to baseline measurements, there was no difference in terms of chronic effect. DNA methylation increased during the acute phase of salicylate administration, whereas it returned to initial levels during the chronic phase.Conclusion: Salicylate-induced changes in DPOAE responses may be related to prestin-gene methylation. These results may have important implications for salicylate ototoxicity.

The influence of rapid growth on sodium salicylate pharmacokinetics in male turkeys

The aim of this study was to assess the influence of growth on the pharmacokinetics of sodium salicylate (SS) in male turkeys. SS was administered intravenously at a dose of 50 mg/kg. Plasma drug concentrations were assessed by high-performance liquid chromatography, and pharmacokinetic parameters were calculated by noncompartmental analysis. As the age increased from 6 to 13 weeks (body weight increase from 2.35 to 9.43 kg), median body clearance decreased from 1.34 to 0.87 ml/min/kg. This caused a significant increase in the median mean residence time from 3.42 to 4.44 hr. Elimination phase proved to be biphasic and two elimination half-lives (T_1/2el ) were distinguished. Whereas T_1/2el1 was found to increase with age by 128%, T_1/2el2 represented a later but faster and less age-dependent phase of elimination (increase by 56% in the respective groups). Volume of distribution decreased with age. These effects may lead to different therapeutic response to SS in turkeys of different age and body weights.

Diazepam reduces excitability of amygdala and further influences auditory cortex following sodium salicylate treatment in rats

CONCLUSION

Diazepam can reduce the excitability of lateral amygdala and eventually suppress the excitability of the auditory cortex in rats following salicylate treatment, indicating the regulating effect of lateral amygdala to the auditory cortex in the tinnitus procedure.

OBJECTIVE

To study the spontaneous firing rates (SFR) of the auditory cortex and lateral amygdala regulated by diazepam in the tinnitus rat model induced by sodium salicylate.

MATERIALS AND METHODS

This study first created a tinnitus rat modal induced by sodium salicylate, and recorded SFR of both auditory cortex and lateral amygdala. Then diazepam was intraperitoneally injected and the SFR changes of lateral amygdala recorded. Finally, diazepam was microinjected on lateral amygdala and the SFR changes of the auditory cortex recorded.

RESULTS

Both SFRs of the auditory cortex and lateral amygdala increased after salicylate treatment. SFR of lateral amygdala decreased after intraperitoneal injection of diazepam. Microinjecting diazepam to lateral amygdala decreased SFR of the auditory cortex ipsilaterally and contralaterally.

Sodium salicylate reduces the level of GABAB receptors in the rat's inferior colliculus

Previous studies have indicated that sodium salicylate (SS) can cause hearing abnormalities through affecting the central auditory system. In order to understand central effects of the drug, we examined how a single intraperitoneal injection of the drug changed the level of subunits of the type-B γ-aminobutyric acid receptor (GABAB receptor) in the rat's inferior colliculus (IC). Immunohistochemical and western blotting experiments were conducted three hours following a drug injection, as previous studies indicated that a tinnitus-like behavior could be reliably induced in rats within this time period. Results revealed that both subunits of the receptor, GABABR1 and GABABR2, reduced their level over the entire area of the IC. Such a reduction was observed in both cell body and neuropil regions. In contrast, no changes were observed in other brain structures such as the cerebellum. Thus, a coincidence existed between a structure-specific reduction in the level of GABAB receptor subunits in the IC and the presence of a tinnitus-like behavior. This coincidence likely suggests that a reduction in the level of GABAB receptor subunits was involved in the generation of a tinnitus-like behavior and/or used by the nervous system to restore normal hearing following application of SS.

Salicylate-induced hearing loss and gap detection deficits in rats

To test the "tinnitus gap-filling" hypothesis in an animal psychoacoustic paradigm, rats were tested using a go/no-go operant gap detection task in which silent intervals of various durations were embedded within a continuous noise. Gap detection thresholds were measured before and after treatment with a dose of sodium salicylate (200 mg/kg) that reliably induces tinnitus in rats. Noise-burst detection thresholds were also measured to document the amount of hearing loss and aid in interpreting the gap detection results. As in the previous human psychophysical experiments, salicylate had little or no effect on gap thresholds measured in broadband noise presented at high-stimulus levels (30-60 dB SPL); gap detection thresholds were always 10 ms or less. Salicylate also did not affect gap thresholds presented in narrowband noise at 60 dB SPL. Therefore, rats treated with a dose of salicylate that reliably induces tinnitus have no difficulty detecting silent gaps as long as the noise in which they are embedded is clearly audible.

Additive cytotoxic effects of dihydroartemisinin and sodium salicylate on cancer cells

BACKGROUND/AIM

The standard methods of chemotherapy in cancer treatment are expensive and pose serious health effects. The present study investigates an alternative chemotherapy by testing the combined treatment of two drugs on leukemia cells: dihydroartemisinin (DHA) and sodium salicylate (SS).

MATERIALS AND METHODS

Cells were divided into 4 treatment groups: a control, treatment with DHA-only, treatment with SS-only, and treatment with both DHA and SS. Cells were counted immediately before the addition of any reagents (0-h count), and at 24, 48, and 72 h after treatment.

RESULTS AND CONCLUSION

At low concentrations, the combination of DHA and SS significantly reduced cancer cell proliferation, although no synergistic interaction between the two drugs was found. Even without a clear synergistic interaction, the combination of DHA and SS provides a safe and affordable form of cancer treatment.

Potent reactive oxygen species-JNK-p38 activation by sodium salicylate potentiates death of primary effusion lymphoma cells

BACKGROUND

Primary effusion lymphoma (PEL) is a rare but aggressive form of non-Hodgkin's B-cell lymphoma in immunodeficient patients. Resistance to conventional chemotherapeutic regimens is common in PEL and contributes to a very poor prognosis; hence, novel potent anti-PEL agents are required. Anticancer effects of non-steroidal anti-inflammatory drugs (NSAIDs) are well-established in epithelial cancer but are unclear in hematological malignancies. Therefore, the anticancer activities of selected NSAIDs, sodium salicylate (NaS), on PEL cell lines are of interest.

MATERIALS AND METHODS

Anti-proliferation of NaS on PEL cell lines was shown by MTT. Apoptosis induction and caspase activations were determined by flow cytometry analysis. ROS production was accessed by DCFH-DA. Western blot was performed to determine molecular mechanisms.

RESULTS

NaS effectively inhibited cell proliferation of all PEL cell lines. Caspase-dependent apoptosis was demonstrated and simultaneous induction of reactive oxygen species production and c-Jun N-terminal kinases (JNK)-p38 activation was observed prior to apoptosis induction, and these might be responsible for NaS-induced apoptosis.

CONCLUSION

Significant anticancer effects of NaS on PEL cell lines were found. A novel role of NaS for PEL treatment is suggested.

Automated evaluation of pharmaceutically active ionic liquids' (eco)toxicity through the inhibition of human carboxylesterase and Vibrio fischeri

The toxicity of 16 pharmaceutical active ionic liquids (IL-APIs) was evaluated by automated approaches based on sequential injection analysis (SIA). The implemented bioassays were centered on the inhibition of human carboxylesterase 2 and Vibrio fischeri, in the presence of the tested compounds. The inhibitory effects were quantified by calculating the inhibitor concentration required to cause 50% of inhibition (EC50). The EC50 values demonstrated that the cetylpyridinium group was one of the most toxic cations and that the imidazolium group was the less toxic. The obtained results provide important information about the safety of the studied IL-APIs and their possible use as pharmaceutical drugs. The developed automated SIA methodologies are robust screening bioassays, and can be used as a generic tools to identify the (eco)toxicity of the structural elements of ILs, contributing to a sustainable development of drugs.

Pro-inflammatory cytokine-mediated ferroportin down-regulation contributes to the nigral iron accumulation in lipopolysaccharide-induced Parkinsonian models

Pro-inflammatory cytokines induced by inflammation and iron accumulation in the substantia nigra (SN) have been implicated in the pathogenesis of Parkinson's disease (PD). In the present study, we aimed to investigate the relationship between inflammation and iron accumulation in a lipopolysaccharide (LPS)-induced Parkinsonian rat model. The activation of glial cells and elevated levels of pro-inflammatory cytokines were observed in the SN of LPS models, accompanied by iron deposits in the same region. Moreover, ferroportin (Fpn), the only channel for iron export, was down-regulated. SH-SY5Y dopaminergic cells were pre-incubated with conditioned media enriched in pro-inflammatory cytokines, and abnormal iron deposits and a drop of Fpn were observed. The expression of heme oxygenase-1 (HO-1) was also upregulated in vivo and in vitro. These results suggested that pro-inflammatory cytokines might induce Fpn downregulation, which leads to iron accumulation and dopaminergic neurons' degeneration in PD. HO-1 may also contribute to the iron accumulation in neurons, but its mechanism needs to be further investigated.

The CaMV 35S promoter has a weak expression activity in dark grown tissues of moss Physcomitrella patens

The constitutive Cauliflower Mosaic Virus 35S promoter (CaMV 35S) is widely used as a tool to express recombinant proteins in plants, but with different success. We previously showed that the expression of an F-actin marker, GFP-talin, in Physcomitrella patens using the CaMV 35S promoter failed to homogenously label moss tissues. Here, we show a significant diminution of the GFP fluorescence in dark grown old moss cells and complete lack of labelling in newly differentiated cells. Furthermore, we demonstrate that stable moss lines harbouring a resistance cassette driven by the CaMV 35S are unable to grow in darkness in the presence of the antibiotic. In contrast to the CaMV 35S, the heat inducible promoter, hsp17.3B showed uniform expression pattern in all cells and tissues following a mild heat shock.

Analysis of bulk sample of salicylic Acid by application of hydrotropic solubilization method

In the present investigation, the poorly water-soluble drug, salicylic acid has been solubilized using 0.5 M ibuprofen sodium and 2.0 M sodium salicylate solution as hydrotropic agents for the titrimetric analysis precluding the use of organic solvents. Both hydrotropes are economic and pollution-free. The mean percent estimation of salicylic acid estimated in bulk sample by Indian Pharmacopoeial method is 98.78%. The mean percent estimation by ibuprofen sodium method and sodium salicylate method are 99.25% and 98.82%, respectively. The results of analysis by the proposed method are very close to the results of analysis by the standard method. This confirms the accuracy of the proposed method. The proposed method was validated statistically by low values of statistical parameters viz. standard deviation, percent coefficient of variation and standard error. The proposed method is new, accurate, simple and economic.

Elevated NF-kappaB responses and FLIP levels in leukemic but not normal lymphocytes: reduction by salicylate allows TNF-induced apoptosis

As its name suggests, tumor necrosis factor (TNF) is known to induce cytotoxicity in a wide variety of tumor cells and cell lines. However, its use as a chemotherapeutic drug has been limited by its deleterious side effects of systemic shock and widespread inflammatory responses. Some nonsteroidal antiinflammatory drugs, such as sodium salicylate, have been shown to have a chemopreventive role in certain forms of cancer. Here, we reveal that sodium salicylate selectively enhances the apoptotic effects of TNF in human erythroleukemia cells but does not affect primary human lymphocytes or monocytes. Sodium salicylate did not affect the intracellular distribution of TNF receptors (TNFRs) but stimulated cell surface TNFR2 shedding. Erythroleukemia cells were shown to possess markedly greater basal NF-kappaB responses and elevated Fas-associated protein with death domain-like IL-1 converting enzyme (FLIP) levels. Sodium salicylate achieved its effects by reducing the elevated NF-kappaB responsiveness and FLIP levels and restoring the apoptotic response of TNF rather than the proliferative/proinflammatory effects of the cytokine in these cancer cells. Inhibition of NF-kappaB or FLIP levels in human erythroleukemia cells by pharmacological or molecular-biological means also resulted in switching the character of these cells from a TNF-responsive proliferative phenotype into an apoptotic one. These findings expose that the enhanced proliferative nature of human leukemia cells is caused by elevated NF-kappaB and FLIP responses and basal levels, reversible by sodium salicylate to allow greater apoptotic responsiveness of cytotoxic stimuli such as TNF. Such findings provide insight into the molecular mechanisms by which human leukemia cells can switch from a proliferative into an apoptotic phenotype.