Uncovering the protective potential of vanillic acid against traumatic brain injury-induced cognitive decline in male rats: Insights into underlying mechanisms

Traumatic brain injury (TBI) is a significant contributor to global mortality and disability, and there is still no specific drug available to treat cognitive deficits in survivors. Vanillic acid (VA), a bioactive phenolic compound, has shown protective effects in various models of neurodegeneration; however, its impact on TBI outcomes remains elusive. Therefore, this study aimed to elucidate the possible role of VA in ameliorating TBI-induced cognitive decline and to reveal the mechanisms involved. TBI was induced using the Marmarou impact acceleration model to deliver an impact force of 300 g, and treatment with VA (50 mg/kg; P.O.) was initiated 30 minutes post-TBI. The cognitive performance, hippocampal long-term potentiation (LTP), oxidative stress markers, neurological function, cerebral edema, and morphological changes were assessed at scheduled points in time. TBI resulted in cognitive decline in the passive avoidance task, impaired LTP in the perforant path-dentate gyrus (PP-DG) pathway, increased hippocampal oxidative stress, cerebral edema, neurological deficits, and neuronal loss in the rat hippocampus. In contrast, acute VA administration mitigated all the aforementioned TBI outcomes. The data suggest that reducing synaptic plasticity impairment, regulating oxidative and antioxidant defense, alleviating cerebral edema, and preventing neuronal loss by VA can be at least partially attributed to its protection against TBI-induced cognitive decline.

Underlying mechanisms behind the neuroprotective effect of vanillic acid against diabetes-associated cognitive decline: An in vivo study in a rat model

Hippocampal synaptic dysfunction, oxidative stress, neuroinflammation, and neuronal loss play critical roles in the pathophysiology of diabetes-associated cognitive decline (DACD). The study aimed to investigate the effects of vanillic acid (VA), a phenolic compound, against DACD and explore the potential underlying mechanisms. Following confirmation of diabetes, rats were treated with VA (50 mg/kg/day; P.O.) or insulin (6 IU/rat/day; S.C.) for 8 consecutive weeks. The cognitive performance of the rats was evaluated using passive-avoidance and water-maze tasks. Long-term potentiation (LTP) was induced at hippocampal dentate gyrus (DG) synapses in response to high-frequency stimulation (HFS) applied to the perforant pathway (PP) to evaluate synaptic plasticity. Oxidative stress factors, inflammatory markers, and histological changes were evaluated in the rat hippocampus. This study showed that streptozotocin (STZ)-induced diabetes caused cognitive decline that was associated with inhibition of LTP induction, suppression of enzymatic antioxidant activities, enhanced lipid peroxidation, elevated levels of inflammatory proteins, and neuronal loss. Interestingly, chronic treatment with VA alleviated blood glucose levels, improved cognitive decline, ameliorated LTP impairment, modulated oxidative-antioxidative status, inhibited inflammatory response, and prevented neuronal loss in diabetic rats at a level comparable to insulin therapy. The results suggest that the antihyperglycemic, antioxidative, anti-inflammatory, and neuroplastic properties of VA may be the mechanisms behind its neuroprotective effect against DACD.

Vanillic Acid Ameliorates Demyelination in a Cuprizone-Induced Multiple Sclerosis Rat Model: Possible Underlying Mechanisms

OBJECTIVE

To investigate the effect of vanillic acid (VA) on a Cuprizone (Cup) demyelinating rat model and the mechanisms behind such effect.

METHODS

Thirty adult male Sprague Dawley (SD) rats were randomly divided into three groups: control, Cuprizone, and VA groups. Cuprizone was administrated at a dose of 450 mg/kg per day orally via gastric gavage for 5 weeks. The nerve conduction velocity (NCV) was studied in an isolated sciatic nerve, and then the sciatic nerve was isolated for histopathological examination, electron microscope examination, immunohistochemical staining, and biochemical and PCR assay. The level of IL17 was detected using ELISA, while the antioxidant genes Nrf2, HO-1 expression at the level of mRNA, expression of the myelin basic protein (MBP), interferon-gamma factor (INF)-γ and tumor necrosis factor (TNF)-α, and apoptotic marker (caspase-3) were measured using immunohistochemistry in the sciatic nerve.

RESULTS

There was a significant reduction in NCV in Cup compared to normal rats (p < 0.001), which was markedly improved in the VA group (p < 0.001). EM and histopathological examination revealed significant demyelination and deterioration of the sciatic nerve fibers with significant improvement in the VA group. The level of IL17 as well as the expression of INF-γ and caspase-3 were significantly increased with a significant reduction in the expression of MBP, Nrf2, and HO-1 in the sciatic nerve (p < 0.01), and VA treatment significantly improved the studied parameters (p < 0.01).

CONCLUSION

The current study demonstrated a neuroprotective effect for VA against the Cup-induced demyelinating rat model. This effect might be precipitated by the inhibition of inflammation, oxidative stress, and apoptosis.

Amomum subulatum fruits protect against radiation-induced esophagitis by regulating antioxidant status and inflammatory responses

Radiation esophagitis (RE) is an inimical event that requires proper management while carrying out radiotherapy for thoracic cancers. The present study investigates the protective effect of dry fruits of the culinary and folkloric spice Amomum subulatum against experimental thoracic radiation-induced esophagitis. C57BL/6 mice were subjected to 25 Gy whole thorax irradiation and administered with 250 mg/kg body weight of methanolic extract of A. subulatum dry fruits (MEAS) orally for four consecutive weeks. Changes in tissue antioxidant activities, oxidative stress parameters, expression of antioxidant, inflammation, and fibrosis-related genes were observed. Administration of MEAS boosted antioxidant status, thereby reducing radiation-induced oxidative stress in the esophagus. PCR (polymerase chain reaction) results showed decreased expression of apoptosis, inflammation, and fibrosis-associated genes as well as increased expression of vital cytoprotective and antioxidant genes in MEAS-treated mice, manifesting its protective effect against radiation-induced oxidative stress, inflammatory responses, and fibrosis in the esophagus. Further, histopathology, immunohistochemistry (Cyclooxygenase-2), and Masson's Trichrome staining ascertained the protective effect of MEAS in alleviating radiation-induced esophageal injury. The synergistic effect of bioactive phytochemicals in MEAS with potent antioxidant and anti-inflammatory efficacies might have contributed to its mitigating effect against RE. Taken together, our results ascertained the radioprotective potential of MEAS, suggesting its possible nutraceutical application as a radiation countermeasure.

Vanillic acid abrogates cisplatin-induced ovotoxicity through activating Nrf2 pathway

Although cisplatin (CDDP) is an effective anticancer agent, the ovotoxicity that can occur in female patients limits its use. Oxidative stress (OS) and inflammation are known to contribute to CDDP-induced ovotoxicity. Vanillic acid (VA) is a dietary herbal secondary metabolite with high free radical scavenging activity. It was aimed to evaluate the therapeutic effects of VA against CDDP-induced ovotoxicity in rats in this study for the first time. Ovotoxicity was achieved with a single dose of CDDP (5 mg/kg) in female rats. The therapeutic effect of VA was evaluated with 3-day administration of two different doses (5 and 10 mg/kg). While OS, inflammation, endoplasmic reticulum stress (ERS) and apoptosis markers were measured in tissue samples, the levels of reproductive hormones were determined in serum samples using colorimetric methods. The results showed that CDDP-induced nuclear factor erythroid 2-associated factor 2 (Nrf2) inhibition combined with increased OS, inflammation, ERS and apoptosis increased ovarian damage. VA treatments reversed these changes via activating Nrf2 pathway dose-dependently. In addition, histopathological findings also supported the biochemical results. VA may be a good therapeutic molecule candidate for CDDP-induced ovarian damage due to strong antioxidant and Nrf2 activator properties.

Protective effects of vanillic acid on autistic-like behaviors in a rat model of maternal separation stress: Behavioral, electrophysiological, molecular and histopathological alterations

Compounds derived from herbs exhibit a range of biological properties, including anti-inflammatory, antioxidant, and neuroprotective properties. However, the exact mechanism of action of these compounds in various neurological disorders is not fully discovered yet. Herein, the present work detected the effect of Vanillic acid (VA), a widely-used flavoring agent derived from vanillin, on autistic-like behaviors to assess the probable underlying mechanisms that mediate behavioral, electrophysiological, molecular, and histopathological alterations in the rat model of maternal separation (MS) stress. Maternal separated rats were treated with VA (25, 50, and 100 mg/kg interperitoneally for 14 days). In addition, anxiety-like, autistic-like behaviors, and learning and memory impairment were evaluated using various behavioral tests. Hippocampus samples were assessed histopathologically by H&E staining. Levels of malondialdehyde (MDA) and antioxidant capacity (by the FRAP method), as well as nitrite levels, were measured in brain tissue. Moreover, gene expression of inflammatory markers (IL-1β, TLR-4, TNF-α, and NLRP3) was evaluated in the hippocampus. Electrophysiological alterations were also estimated in the hippocampus by long-term potentiation (LTP) assessments. Results showed that VA reversed the negative effects of MS on behavior. VA increased the diameter and decreased the percentage of dark neurons in the CA3 area. Accordingly, VA decreased MDA and nitrite levels and increased the antioxidant capacity in brain samples and decreased the expression of all inflammatory genes. VA treated rats showed significant improvements in all LTP parameters. This study provided evidence suggesting a possible role for VA in preventing autism spectrum disorder (ASD) by regulating immune signaling.

Cardioprotective potential of vanillic acid

Nowadays, cardiovascular diseases (CVDs) are a global threat to public health, accounting for almost one-third of all deaths worldwide. One of the key mechanistic pathways contributing to the development of CVDs, including cardiotoxicity (CTX) and myocardial ischaemia-reperfusion injury (MIRI) is oxidative stress (OS). Increased generation of reactive oxygen species (ROS) is closely associated with decreased antioxidant capacity and mitochondrial dysfunction. Currently, despite the availability of modern pharmaceuticals, dietary-derived antioxidants are becoming more popular in developed societies to delay the progression of CVDs. One of the antioxidants derived from herbs, fruits, whole grains, juices, beers, and wines is vanillic acid (VA), which, as a phenolic compound, possesses different therapeutic properties, including cardioprotective. Based on experimental evidence, VA improves mitochondrial function as a result of the reduction in ROS production, aggravates antioxidative status, scavenges free radicals, and reduces levels of lipid peroxidation, thereby decreasing cardiac dysfunction, in particular CTX and MIRI. Considering the role of OS in the pathophysiology of CVDs, the purpose of this study is to comprehensively address recent evidence on the antioxidant importance of VA in the cardiovascular system.

Amomum subulatum mitigates experimental thoracic radiation-induced lung injury by regulating antioxidant status and inflammatory responses

Radiation-induced lung injury (RILI) is one of the most prominent complications of thoracic radiotherapy for which effective therapy is still lacking. This study investigates the nutraceutical potential of the culinary spice Amomum subulatum in mitigating thoracic radiation-induced pneumonitis (RP) and pulmonary fibrosis (PF). Mouse models of RP and PF were established by whole thorax irradiation at a dose of 25 gray. C57BL/6 mice were administered with 250 mg per kg body weight of methanolic extract of A. subulatum dry fruits (MEAS) for four consecutive weeks and observed for changes in lung tissue antioxidant activities, oxidative stress parameters, and expression of antioxidant, inflammation, and fibrosis-related genes by semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) and real-time PCR analysis, and histology analysis. MEAS administration reduced radiation-induced oxidative stress by enhancing the expression of Nrf2 and its target genes. Irradiation increased gene expression of inflammatory mediators and lung histology further confirmed the characteristics of RP, which were reduced by MEAS treatment. Immunohistochemistry analysis revealed the potential of MEAS in reducing the radiation-induced elevation of cyclooxygenase 2 expression in the lungs. The late sequel of RILI was manifested as PF, characterized by the elevated expression of pro-fibrotic genes and increased collagen content. However, MEAS administration markedly reduced radiation-induced fibrotic changes in the lungs. These effects might be attributed to the synergistic effect of bioactive polyphenols in MEAS with antioxidant, anti-inflammatory, and anti-fibrotic efficacies. Taken together, this study demonstrates the potential of MEAS in mitigating RILI, suggesting the possible nutraceutical application of A. subulatum against radiation toxicities.

Neuroprotection impact of biochanin A against pentylenetetrazol-kindled mice: Targeting NLRP3 inflammasome/TXNIP pathway and autophagy modulation

Recurrent seizures characterize epilepsy, a complicated and multifaceted neurological disease. Several neurological alterations, such as cell death and the growth of gorse fibers, have been linked to epilepsy. The dentate gyrus of the hippocampus is particularly vulnerable to neuronal loss and abnormal neuroplastic changes in the pentylenetetrazol (PTZ) kindling model. Biochanin A has potent anti-inflammatory and antioxidant properties, according to previous evidence and its possible impact in epilepsy has never previously been claimed. The current work aimed to investigate biochanin A's anti-epileptic potential in PTZ-induced kindling model in mice. Chronic epilepsy was established in mice by giving PTZ (35 mg/kg, i.p) every other day for 21 days. Biochanin A (20 mg/kg) was given daily till the end of the experiment. Biochanin A pretreatment significantly reduced the severity of epileptogenesis by 51.7% and downregulated the histological changes in the CA3 region of the hippocampus by 42% along with displaying antioxidant/anti-inflammatory efficacy through upregulated hemeoxygenase-1 (HO-1) and, erythroid 2-related factor 2 (Nrf2) levels in the brain by 1.9-fold and 2-fold respectively, parallel to reduction of malondialdehyde (MDA), myeloperoxidase (MPO), glial fibrillary acidic protein (GFAP) and L-glutamate/IL-1β/TXNIB/NLRP3 axis. Moreover, biochanin A suppressed neuronal damage by reducing the astrocytes' activation and significantly attenuated the PTZ-induced increase in LC3 levels by 55.5%. Furthermore, molecular docking findings revealed that BIOCHANIN A has a higher affinity for phosphoinositide 3-kinase (PI3k), threonine kinase2 (AKT2), and mammalian target of rapamycin complex 1 (mTORC1) indicating the neuroprotective and anti-epileptic characteristics of biochanin A in the brain tissue of PTZ-kindled mice.

A Novel Pathway Phenotype of Temporal Lobe Epilepsy and Comorbid Psychiatric Disorders: Results of Precision Nomothetic Medicine

No precision medicine models of temporal lobe epilepsy (TLE) and associated mental comorbidities have been developed to date. This observational study aimed to develop a precision nomothetic, data-driven comorbid TLE model with endophenotype classes and pathway phenotypes that may have prognostic and therapeutical implications. We recruited forty healthy controls and 108 TLE patients for this research and assessed TLE and psychopathology (PP) features as well as oxidative stress (OSTOX, e.g., malondialdehyde or MDA, lipid hydroperoxides, and advanced oxidation protein products) and antioxidant (paraoxonase 1 or PON1 status, -SH groups, and total radical trapping potential or TRAP) biomarkers. A large part (57.2%) of the variance in a latent vector (LV) extracted from the above TLE and PP features was explained by these OSTOX and antioxidant biomarkers. The PON1 Q192R genetic variant showed indirect effects on this LV, which were completely mediated by PON1 activity and MDA. Factor analysis showed that a common core could be extracted from TLE, PP, OSTOX and antioxidant scores, indicating that these features are manifestations of a common underlying construct, i.e., a novel pathway phenotype of TLE. Based on the latter, we constructed a new phenotype class that is characterized by increased severity of TLE, PP and OSTOX features and lowered antioxidant defenses. A large part of the variance in episode frequency was explained by increased MDA, lowered antioxidant, and nitric oxide metabolite levels. In conclusion, (a) PP symptoms belong to the TLE phenome, and the signal increased severity; and (b) cumulative effects of aldehyde formation and lowered antioxidants determine epileptogenic kindling.