The effects of ferulic acid on nucleus pulposus cells under hydrogen peroxide-induced oxidative stress

The Sanbi Decoction alleviates intervertebral disc degeneration in rats through intestinal flora and serum metabolic homeostasis modulation

BACKGROUND

Intervertebral disc degeneration (IVDD) is an essential cause of low back pain (LBP), the incidence of which has risen in recent years and is progressively younger, but treatment options are limited, placing a serious economic burden on society. Sanbi decoction (SBD) is an important classical formula for the treatment of IVDD, which can significantly improve patients' symptoms and is a promising alternative therapy.

PURPOSE

The aim of this study is to investigate the safety and efficacy of SBD in the treatment of IVDD and to explore the underlying mechanisms by using an integrated analytical approach of microbiomics and serum metabolomics, as well as by using molecular biology.

METHODS

A rat IVDD puncture model was established and treated by gavage with different concentrations of SBD, and clean faeces, serum, liver, kidney, and intervertebral disc (IVD) were collected after 4 weeks. We assessed the safety by liver and kidney weighing, functional tests and tissue staining, the expression of tumor necrosis factor-alpha (TNF-ɑ), interleukin 1β (IL-1β) and interleukin 6 (IL-6) inflammatory factors in serum was detected by ELISA kits, and X-ray test, magnetic resonance imaging (MRI) examination, immunohistochemistry (IHC), western blotting (WB), hematoxylin-eosin (HE) staining and safranin O-fast green (SO/FG) staining were used to assess the efficacy. Finally, we performed 16S rRNA sequencing analysis on the faeces of different groups and untargeted metabolomics on serum and analyzed the association between them.

RESULTS

SBD can effectively reduce the inflammatory response, regulate the metabolic balance of extracellular matrix (ECM), improve symptoms, and restore IVD function. In addition, SBD can significantly improve the diversity of intestinal flora and maintain the balance. At the phylum level, SBD greatly increased the relative abundance of Patescibacteria and Actinobacteriota and decreased the relative abundance of Bacteroidota. At the genus level, SBD significantly increased the relative abundance of Clostridia_UCG-014, Enterorhabdus, and Adlercreutzia, and decreased the relative abundance of Ruminococcaceae_UCG-005 (p < 0.05). Untargeted metabolomics indicated that SBD significantly improved serum metabolites and altered serum expression of 4alpha-phorbol 12,13-didecanoate (4alphaPDD), euscaphic acid (EA), alpha-muricholic acid (α-MCA), 5-hydroxyindoleacetic acid (5-HIAA), and kynurenine (Kyn) (p < 0.05), and the metabolic pathways were mainly lipid metabolism and amino acid metabolism.

CONCLUSIONS

This study demonstrated that SBD can extensively regulate intestinal flora and serum metabolic homeostasis to reduce inflammatory response, inhibit the degradation of ECM, restore IVD height and water content to achieve apparent therapeutic effect for IVDD.

Tea Polyphenol Attenuates Oxidative Stress-Induced Degeneration of Intervertebral Discs by Regulating the Keap1/Nrf2/ARE Pathway

Objective

Intervertebral disc degeneration (IDD) and low back pain caused by IDD have attracted public attention owing to their extremely high incidence and disability rate. Oxidative stress is a major cause of IDD. Tea polyphenols (TP) are natural-derived antioxidants extracted from tea leaves. This study explored the protective role of TP on the nucleus pulposus cells (NPCs) of intervertebral discs and their underlying mechanism.

Methods

An in vitro model of H₂O₂-induced degeneration of NPCs was established. RT-qPCR and western blotting were used to detect the mRNA and protein expression of the targets. An in vivo model of IDD was established via acupuncture of the intervertebral disc. Radiological imaging and histological staining were performed to evaluate the protective role of TP.

Results

H₂O₂ contributed to NPC degeneration by inducing high levels of oxidative stress. TP treatment effectively increased the expression of nucleus pulposus matrix-associated genes and reduced the expression of degeneration factors. Further mechanistic studies showed that TP delayed H₂O₂-mediated NPC degeneration by activating the Keap1/Nrf2/ARE pathway. In vivo experiments showed that TP delayed the degeneration of NPCs in rats through the Keap1/Nrf2/ARE pathway.

Conclusion

Our study confirmed that TP activates the Keap1/Nrf2/ARE pathway to exert an antioxidative stress role, ultimately delaying the degeneration of intervertebral discs.

Antioxidant functionalized polymer capsules to prevent oxidative stress

Polymeric capsules exhibit significant potential for therapeutic applications as microreactors, where the bio-chemical reactions of interest are efficiently performed in a spatial and time defined manner due to the encapsulation of an active biomolecule (e.g., enzyme) and control over the transfer of reagents and products through the capsular membrane. In this work, catalase loaded polymer capsules functionalized with an external layer of tannic acid (TA) are fabricated via a layer-by-layer approach using calcium carbonate as a sacrificial template. The capsules functionalised with TA exhibit a higher scavenging capacity for hydrogen peroxide and hydroxyl radicals, suggesting that the external layer of TA shows intrinsic antioxidant properties, and represents a valid strategy to increase the overall antioxidant potential of the developed capsules. Additionally, the hydrogen peroxide scavenging capacity of the capsules is enhanced in the presence of the encapsulated catalase. The capsules prevent oxidative stress in an in vitro inflammation model of degenerative disc disease. Moreover, the expression of matrix metalloproteinase-3 (MMP-3), and disintegrin and metalloproteinase with thrombospondin motif-5 (ADAMTS-5), which represents the major proteolytic enzymes in intervertebral disc, are attenuated in the presence of the polymer capsules. This platform technology exhibits potential to reduce oxidative stress, a key modulator in the pathology of a broad range of inflammatory diseases.

STATEMENT OF SIGNIFICANCE

Oxidative stress damages important cell structures leading to cellular apoptosis and senescence, for numerous disease pathologies including cancer, neurodegeneration or osteoarthritis. Thus, the development of biomaterials-based systems to control oxidative stress has gained an increasing interest. Herein, polymer capsules loaded with catalase and functionalized with an external layer of tannic acid are fabricated, which can efficiently scavenge important reactive oxygen species (i.e., hydroxyl radicals and hydrogen peroxide) and modulate extracellular matrix activity in an in vitro inflammation model of nucleus pulposus. The present work represents accordingly, an important advance in the development and application of polymer capsules with antioxidant properties for the treatment of oxidative stress, which is applicable for multiple inflammatory disease targets.

Systematic study of cell isolation from bovine nucleus pulposus: Improving cell yield and experiment reliability

Differences in matrix compositions in human nucleus pulposus (NP) clinical samples demand different cell isolation protocols for optimal results but there is no clear guide about this to date. Sub-optimal protocols may result in low cell yield, limited reliability of results or even failure of experiments. Cell yield, viability and attachment of cells isolated from bovine NP tissue with different protocols were estimated by cell counting, Trypan blue staining and cell culturing respectively. RNA was extracted from isolated cells and quantified by Nanodrop spectrometry and RT-qPCR. Higher collagenase concentration, longer digestion duration and pronase pre-treatment increased the cell yield. Cell viability remained high (<5% dead cells) even after 0.2% collagenase treatment for overnight. NP cells remained to have high ACAN, COL2A1, CDH2, KRT18, and KRT19 expression compared to muscle cells for different cell isolation conditions tested. Digestion by collagenase alone without the use of pronase could isolate cells from human degenerated NP tissue but clusters of cells were observed. We suggest the use of the disappearance of tissue as an indirect measure of cells released. This study provides a guide for researchers to decide the parameters involved in NP cell isolation for optimal outcome.

Ferulic acid chronic treatment exerts antidepressant-like effect: role of antioxidant defense system

Oxidative stress has been claimed a place in pathophysiology of depression; however, the details of the neurobiology of this condition remains incompletely understood. Recently, treatments employing antioxidants have been thoroughly researched. Ferulic acid (FA) is a phenolic compound with antioxidant and antidepressant-like effects. Herein, we investigated the involvement of the antioxidant activity of chronic oral FA treatment in its antidepressant-like effect using the tail suspension test (TST) and the forced swimming test (FST) in mice. The modulation of antioxidant system in blood, hippocampus and cerebral cortex was assessed after stress induction through TST and FST. Our results show that FA at the dose of 1 mg/kg has antidepressant-like effect without affecting locomotor activity. The stress induced by despair tests was able to decrease significantly the activities of superoxide dismutase (SOD) in the blood, catalase (CAT) in the blood and cerebral cortex and glutathione peroxidase (GSH-Px) in the cerebral cortex. Thiobarbituric acid-reactive substances (TBA-RS) levels were increased significantly in the cerebral cortex. Furthermore, the results show that FA was capable to increase SOD, CAT and GSH-Px activities and decrease TBA-RS levels in the blood, hippocampus and cerebral cortex. These findings demonstrated that FA treatment in low doses is capable to exert antidepressant-like effect with the involvement of the antioxidant defense system modulation.

Protection of feruloylated oligosaccharides from corn bran against oxidative stress in PC 12 cells

Feruloylated oligosaccharides (FOs) were prepared by autoclaving corn bran in oxalic acid (0.6%) solution, and their protection effects against oxidative stress in pheochromocytoma cells (PC 12) cells were investigated. The FOs samples, which comprised a mixture of feruloylated mono- and dipentoses with 4.88% bound ferulic acid (FA), as well as xylose, arabinose, galactose, and glucose amounting to 46.43, 40.46, 3.76, and 8.68% of the total sugars, respectively, were prepared by autoclaving the pretreated corn bran in 0.6% oxalic acid and then further separated. Antioxidant activity was tested by 1,1-diphenyl-2-picrylhydrazyl radical 2,2-diphenyl-1-(2,4,6-trinitrophenyl)hydrazyl (DPPH) scavenging and oxygen radical absorbance capacity (ORAC) methods. Oxidative stress was induced by H2O2 in PC 12 neuronal cell culture model. The results showed that FOs exhibited higher antioxidant activity than free ferulic acid, with an IC50 value of 11 versus 128 μM for DPPH and an ORAC value of 4.77 versus 2.62 μmol Trolox/μmol. Tetrazolium blue assay showed that the addition of FOs with an FA concentration >50 μM significantly increased cell viability after treatment with H2O2. Flow cytometry analysis showed that the addition of FOs at concentrations of 800, 200, and 50 μM significantly decreased the apoptosis rate at the sub-G0 phase from 37.5 to 12.7, 16.2, and 20.9% (P < 0.01), respectively. FOs also significantly decreased the malonic dialdehyde content and lactate dehydrogenase (LDH) activity, but increased superoxide dismutase activity in PC 12 cells treated with H2O2 and prevented the damage of cellular membranes by decreasing the release of LDH to the cultures. The addition of FA at 800 μM showed an effect similar to that of FOs at 200 μM. Therefore, the FOs prepared from corn bran are potential functional ingredients for protection against oxidative stress.

Synthesis and characteristics of (Hydrogenated) ferulic acid derivatives as potential antiviral agents with insecticidal activity

Background

Plant viruses cause many serious plant diseases and are currently suppressed with the simultaneous use of virucides and insecticides. The use of such materials, however, increases the amounts of pollutants in the environment. To reduce environmental contaminants, virucides with insecticidal activity is an attractive option.

Results

A series of substituted ferulic acid amide derivatives 7 and the corresponding hydrogenated ferulic acid amide derivatives 13 were synthesized and evaluated for their antiviral and insecticidal activities. The majority of the synthesized compounds exhibited good levels of antiviral activity against the tobacco mosaic virus (TMW), with compounds 7a, 7b and 7d in particular providing higher levels of protective and curative activities against TMV at 500 μg/mL than the control compound ribavirin. Furthermore, these compounds displayed good insecticidal activities against insects with piercing-sucking mouthparts, which can spread plant viruses between and within crops.

Conclusions

Two series of ferulic acid derivatives have been synthesized efficiently. The bioassay showed title compounds not only inhibit the plant viral infection, but also prevented the spread of plant virus by insect vectors. These findings therefore demonstrate that the ferulic acid amides represent a new template for future antiviral studies.

Evaluation of wound healing activity of ferulic acid in diabetic rats

In diabetic patients, there is impairment in angiogenesis, neovascularisation and failure in matrix metalloproteineases (MMPs), keratinocyte and fibroblast functions, which affects wound healing mechanism. Hence, diabetic patients are more prone to infections and ulcers, which finally result in gangrene. Ferulic acid (FA) is a natural antioxidant found in fruits and vegetables, such as tomatoes, rice bran and sweet corn. In this study, wound healing activity of FA was evaluated in streptozotocin-induced diabetic rats using excision wound model. FA-treated wounds were found to epithelise faster as compared with diabetic wound control group. The hydroxyproline and hexosamine content increased significantly when compared with diabetic wound control. FA effectively inhibited the lipid peroxidation and elevated the catalase, superoxide dismutase, glutathione and nitric oxide levels along with the increase in the serum zinc and copper levels probably aiding the wound healing process. Hence, the results indicate that FA significantly promotes wound healing in diabetic rats.

Thermosensitive hydrogel made of ferulic acid-gelatin and chitosan glycerophosphate

Reactive oxygen species-induced oxidative stress is involved in apoptosis of nucleus pulposus (NP) cells that can alter cellular phenotype and accelerate disc degeneration. Ferulic acid (FA) possesses an excellent antioxidant and anti-inflammatory properties. In the study, we developed the thermosensitive FA-gelatin/chitosan/glycerol phosphate (FA-G/C/GP) hydrogel which was applied as a sustained release system of FA to treat NP cells from the damage caused by oxidative stress. The gelation temperature of the FA-G/C/GP hydrogel was 32.17 °C. NP cells submitted to oxidative stress promoted by H(2)O(2), and post-treated with FA-G/C/GP exhibited down-regulation of MMP-3 and up-regulation aggrecan and type II collagen in mRNA level. The sulfated-glycosaminoglycan production was increased and the apoptosis was inhibited in the post-treatment group. The results suggest that the thermosensitive FA-G/C/GP hydrogel can treat NP cells from the damage caused by oxidative stress and may apply in minimally invasive surgery for NP regeneration.