Procyanidin B2 inhibits lipopolysaccharide‑induced apoptosis by suppressing the Bcl‑2/Bax and NF‑κB signalling pathways in human umbilical vein endothelial cells

Cardiovascular protective effects of natural flavonoids on intestinal barrier injury

Natural flavonoids may be utilized as an important therapy for cardiovascular diseases (CVDs) caused by intestinal barrier damage. More research is being conducted on the protective properties of natural flavonoids against intestinal barrier injury, although the underlying processes remain unknown. Thus, the purpose of this article is to present current research on natural flavonoids to reduce the incidence of CVDs by protecting intestinal barrier injury, with a particular emphasis on intestinal epithelial barrier integrity (inhibiting oxidative stress, regulating inflammatory cytokine expression, and increasing tight junction protein expression). Furthermore, the mechanisms driving intestinal barrier injury development are briefly explored, as well as natural flavonoids having CVD-protective actions on the intestinal barrier. In addition, natural flavonoids with myocardial protective effects were docked with ZO-1 targets to find natural products with higher activity. These natural flavonoids can improve intestinal mechanical barrier function through anti-oxidant or anti-inflammatory mechanism, and then prevent the occurrence and development of CVDs.

Procyanidin B2 mitigates methotrexate-induced hepatic pyroptosis by suppressing TLR4/NF-κB and caspase-3/GSDME pathways

Methotrexate (MTX), a potent chemotherapeutic and immunosuppressive agent, is widely used for cancer and autoimmune diseases. MTX-induced hepatotoxicity is a well-recognized adverse response, even at relatively low doses. This study investigates the possible protective effects of procyanidin B2 (PCB2) on MTX-induced hepatotoxicity. Rats were orally treated with PCB2 (40 mg/kg) for 10 days, followed by a single intraperitoneal MTX injection (20 mg/kg) on day 8. The study also included a positive control group treated with quercetin (20 mg/kg), a known antioxidant, alongside MTX. The results revealed that MTX-induced hepatic injury was evidenced by elevation in serum transaminases. This elevation was accompanied by hepatic oxidative stress due to an imbalance in oxidative/antioxidant markers, specifically elevated malondialdehyde (MDA) and decreased glutathione (GSH) levels and superoxide dismutase (SOD) activity. The inflammatory cytokines, including tumor necrosis factor-alpha (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6), were markedly upregulated in the liver of MTX-intoxicated rats. Additionally, the expressions of nuclear factor kappa B (NF-κB), toll-like receptor 4 (TLR4), caspase-3 and gasdermin E (GSDME) were significantly increased in MTX rats. The use of PCB2 significantly ameliorated the deleterious effect of MTX on previous parameters by restoring oxidant/antioxidant balance, decreasing the inflammatory markers, and normalizing the expression of NF-κB, TLR4, caspase-3 and GSDME. In conclusion, this study uncovered the potential role of PCB2 on MTX-induced hepatotoxicity, confirming its antioxidant, anti-inflammatory, and anti-pyroptosis effects yet, further studies are needed to support its use as a protective therapy against such toxicity.

Bioactive Flavonoids in Protecting Against Endothelial Dysfunction and Atherosclerosis

Atherosclerosis is a common cardiovascular disease closely associated with factors such as hyperlipidaemia and chronic inflammation. Among them, endothelial dysfunction serves as a major predisposing factor. Vascular endothelial dysfunction is manifested by impaired endothelium-dependent vasodilation, enhanced oxidative stress, chronic inflammation, leukocyte adhesion and hyperpermeability, endothelial senescence, and endothelial-mesenchymal transition (EndoMT). Flavonoids are known for their antioxidant activity, eliminating oxidative stress induced by reactive oxygen species (ROS), thereby preventing the oxidation of low-density lipoprotein (LDL) cholesterol, reducing platelet aggregation, alleviating ischemic damage, and improving vascular function. Flavonoids have also been shown to possess anti-inflammatory activity and to protect the cardiovascular system. This review focuses on the protective effects of these naturally-occuring bioactive flavonoids against the initiation and progression of atherosclerosis through their effects on endothelial cells including, but not limited to, their antioxidant, anti-inflammatory, anti-thrombotic, and lipid-lowering properties. However, more clinical evidences are still needed to determine the exact role and optimal dosage of these compounds in the treatment of atherosclerosis.

Procyanidine alleviates bisphenol A-induced apoptosis in TM3 cells via the Nrf2 signaling pathway

Contaminated foods are a major source of bisphenol A (BPA) and are widely used in food packaging. Prolonged exposure to BPA can cause reproductive dysfunction in humans. Procyanidine (PC) is a potent natural antioxidant; however, the exact mechanism by which PC mitigates Leydig cell damage caused by BPA is unknown. In this study, the protective effect of PC against BPA-induced TM3 cell damage was investigated, and the underlying mechanism was assessed. PC treatment attenuates BPA-induced TM3 cell damage by suppressing oxidative stress and inhibiting TM3 apoptosis. In addition, PC upregulates the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and its downstream antioxidant target genes. Treatment with the NRF2 inhibitor ML385 reversed the PC-induced upregulation of the mRNA expression of these genes. Overall, PC may mitigate BPA-induced cell damage by activating the Nrf2 signaling pathway, suggesting that PC supplementation may alleviate BPA toxicity in TM3 cells.

Gut-derived wild blueberry phenolic acid metabolites modulate extrinsic cutaneous damage

As the first line of defense, the skin is equipped with various physiological mechanisms positioned to prevent incoming oxidative damage from numerous environmental insults. With persistent exposure to the environment, understanding ways to augment the skin defenses is paramount in protecting from premature aging. In this study, we investigated the ability of five dietary phenolic metabolites, typically found in the bloodstream after wild blueberry consumption, to successfully defend the skin from UV light exposure in a novel ex vivo co-culture model of human skin explants and primary endothelial cells. Skin explants, placed in transwell inserts, were exposed to UV, and subsequently co-cultured with endothelial cells. When the endothelial cells had been pretreated with the bioactive metabolites at physiological concentrations (hippuric acid 3000 nM, isoferulic acid 1000 nM, salicylic acid 130 nM, benzoic acid 900 nM, α-hydroxyhippuric acid 400 nM) cutaneous damage was prevented on the co-cultured with UV-challenged skin explants. Co-culture with non-pretreated endothelial cells did not protect skin explants. Specifically, the pretreatment was able to reduce skin lipid peroxidation (measured as 4-hydroxynonenal protein adducts), and pro-inflammatory enzymes such as cyclooxygenase 2 (COX-2) and NADPH oxidase 4 (NOX-4). Furthermore, pretreatment with the metabolites prevented UV-induced release of inflammatory cytokines such as IL-1β and IL-8 as well as nitric oxides (NO) levels. In addition, the metabolites showed an impressive ability to prevent the loss of cutaneous structural proteins including involucrin and collagen type 1. Of note, endothelial cells cultured with UV exposed skin explants exhibited increased oxidative stress demonstrated by heme oxygenase-1 (HO-1) up-regulation which was significantly prevented in the metabolite treated models. These findings highlight the ability of dietary polyphenolic metabolites to improve cutaneous defenses against extrinsic stressors.

Procyanidin B2 alleviates oxidized low-density lipoprotein-induced cell injury, inflammation, monocyte chemotaxis, and oxidative stress by inhibiting the nuclear factor kappa-B pathway in human umbilical vein endothelial cells

BACKGROUND

Oxidized low-density lipoprotein (ox-LDL) can initiate and affect almost all atherosclerotic events including endothelial dysfunction. In this text, the role and underlying molecular basis of procyanidin B2 (PCB2) with potential anti-oxidant and anti-inflammatory activities in ox-LDL-induced HUVEC injury were examined.

METHODS

HUVECs were treated with ox-LDL in the presence or absence of PCB2. Cell viability and apoptotic rate were examined by CCK-8 assay and flow cytometry, respectively. The mRNA and protein levels of genes were tested by RT-qPCR and western blot assays, respectively. Potential downstream targets and pathways of apple procyanidin oligomers were examined by bioinformatics analysis for the GSE9647 dataset. The effect of PCB2 on THP-1 cell migration was examined by recruitment assay. The effect of PCB2 on oxidative stress was assessed by reactive oxygen species (ROS) level, malondialdehyde (MDA) content, and mitochondrial membrane potential (MMP).

RESULTS

ox-LDL reduced cell viability, induced cell apoptosis, and facilitated the expression of oxidized low-density lipoprotein receptor 1 (LOX-1), C-C motif chemokine ligand 2 (MCP-1), vascular cell adhesion protein 1 (VCAM-1) in HUVECs. PCB2 alleviated ox-LDL-induced cell injury in HUVECs. Apple procyanidin oligomers triggered the differential expression of 592 genes in HUVECs (|log2fold-change| > 0.58 and adjusted p-value < 0.05). These dysregulated genes might be implicated in apoptosis, endothelial cell proliferation, inflammation, and monocyte chemotaxis. PCB2 inhibited C-X-C motif chemokine ligand 1/8 (CXCL1/8) expression and THP-1 cell recruitment in ox-LDL-stimulated HUVECs. PCB2 inhibited ox-LDL-induced oxidative stress and nuclear factor kappa-B (NF-κB) activation in HUVECs.

CONCLUSION

PCB2 weakened ox-LDL-induced cell injury, inflammation, monocyte recruitment, and oxidative stress by inhibiting the NF-κB pathway in HUVECs.

CircTMEM165 facilitates endothelial repair by modulating mitochondrial fission via miR-192/SCP2 in vitro and in vivo

Constitutive explorations indicate a correlation between circular RNAs (circRNAs) and cardiovascular diseases. However, the involvement of circRNAs in endothelial recuperation and in-stent restenosis (ISR) remains underexplored. CircTMEM165 has first been reported to be highly expressed in hypoxic human umbilical vein endothelial cells (HUVECs). Here, we identified that circTMEM165 was downregulated in ISR patients, inversely correlating with ISR severity. Functionally, circTMEM165 was found to be abundant in endothelial cells, inhibiting inflammation, and adhesion. Particularly, we first observed that circTMEM165 could alleviate HUVECs apoptosis and mitochondrial fission induced by lipopolysaccharide (LPS). Mechanistically, circTMEM165, as a miR-192-3p sponge, enhancing SCP2 expression, which serves as a critical regulator of HUVECs biological functions. Moreover, in vivo, circTMEM165 attenuated intimal hyperplasia and facilitated repair following classic rat carotid artery balloon injury model. These findings investigated the circTMEM165-miR-192-3p-SCP2 axis as a critical determinant of endothelial health and a potential biomarker and therapeutic target for vascular disorders.

Research progress of procyanidins in repairing cartilage injury after anterior cruciate ligament tear

Anterior cruciate ligament (ACL) tear is a common sports-related injury, and cartilage injury always emerges as a serious complication following ACL tear, significantly impacting the physical and psychological well-being of affected individuals. Over the years, efforts have been directed toward finding strategies to repair cartilage injury after ACL tear. In recent times, procyanidins, known for their anti-inflammatory and antioxidant properties, have emerged as potential key players in addressing this concern. This article focuses on summarizing the research progress of procyanidins in repairing cartilage injury after ACL tear. It covers the roles, mechanisms, and clinical significance of procyanidins in repairing cartilage injury following ACL tear and explores the future prospects of procyanidins in this domain. This review provides novel insights and hope for the repair of cartilage injury following ACL tear.

Effect of miR-412-5p-loaded exosomes in H9c2 cardiomyocytes via the MAPK pathway

Objectives

MicroRNAs (miRNAs) are small non-coding RNAs that function in all biological processes. Recent findings suggest that exosomes, which are small vesicles abundantly secreted by various cell types, can transport miRNAs to target cells. Here, we elucidated the effect of miRNA-loaded exosomes on lipopolysaccharide (LPS)-induced inflammation in H9c2 cardiomyocytes.

Materials and Methods

Exosomes were isolated from mesenchymal stem cells (MSC) and loaded with miR-412-5p. Additionally, the effect of the miR-412-5p-loaded exosomes on LPS-induced inflammation in H9c2 cardiomyocytes was evaluated by assessing the levels of nitric oxide (NO), reactive oxygen species (ROS), and prostaglandin E2 (PGE2). The expression of cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), inflammatory cytokines, and mitogen-activated protein kinase (MAPK) signaling factors was evaluated using reverse transcription-quantitative PCR and western blotting.

Results

miR-412-5p-loaded exosomes inhibited LPS-induced secretion of inflammatory mediators (NO, PGE2, and ROS), pro-inflammatory cytokines (IL-1β and IL-6), and COX-2 and iNOS expression. Additionally, miR-412-5p-loaded exosomes significantly decreased the expression of MAPK signaling molecules, including p-extracellular signal-regulated kinase (ERK), p-p38, and p-Jun kinase (JNK), in H9c2 cardiomyocytes.

Conclusion

These findings showed that miR-412-5p-loaded exosomes ameliorated LPS-induced inflammation in H9c2 cardiomyocytes by inhibiting COX-2 and iNOS expression, inflammatory mediators, and pro-inflammatory cytokines via the MAPK pathway. The findings indicate that miR-412-5p-loaded exosomes may be effective for the prevention of myocardial injury.

Effects of grape seed-derived proanthocyanidin B2 pretreatment on oxidative stress, endoplasmic reticulum stress and apoptosis of renal tubular epithelial cells in renal ischemia-reperfusion injury model of mice

PURPOSE

To investigate the effect of grape seed-derived proanthocyanidin B2 (GSPB2) pretreatment on acute renal ischemia-reperfusion injury model of mice.

METHODS

50 mice were divided into 5 groups: Sham group: mice were treated with right nephrectomy. GSPB2 group: GSPB2 was injected intraperitoneally 45 min before right nephrectomy. IRI group: right kidney was resected and the left renal arteriovenous vessel was blocked for 45 min. GSPB2 + IRI group: GSPB2 was intraperitoneally injected 45 min before IRI established. GSPB2 + BRU + IRI group: GSPB2 and brusatol (BRU) were injected intraperitoneally 45 min before IRI established. Creatinine and urea nitrogen of mice were detected, and the kidney morphology and pathological changes of each group were detected by HE staining, PAS staining and transmission electron microscopy. Expressions of Nrf2, HO-1, GRP78, CHOP, and cleaved-caspase3 were detected by immunofluorescence staining and western blotting.

RESULTS

Morphology and mitochondrial damages of kidney in GSPB2 + IRI group were significantly alleviated than those in IRI group. Expression levels of Nrf2 and HO-1 were significantly higher in GSPB2 + IRI group than those in IRI group. Expression levels of GRP78, CHOP and cleaved-caspase3 were significantly lower in GSPB2 + IRI group than those in IRI group. However, compared to GSPB2 + IRI group, protective effects of GSPB2 pretreatment were weakened in GSPB2 + BRU + IRI group.

CONCLUSIONS

GSPB2 pretreatment could alleviate oxidative stress damage and reduce apoptosis of renal tubular epithelial cells, which might be related to activating the antioxidant system, up-regulating the expression of Nrf2 and HO-1, inhibiting the expressions of GRP78, CHOP and cleaved-caspase3. However, the protective effect could be reversed by brusatol.

Procyanidin B2: A promising multi-functional food-derived pigment for human diseases

Natural edible pigments play a paramount part in the food industry. Procyanidin B2 (PB2), one of the most representative naturally occurring edible pigments, is usually isolated from the seeds, fruits, and leaves of lots of common plants, such as grapes, Hawthorn, black soybean, as well as blueberry, and functions as a food additive in daily life. Notably, PB2 has numerous bioactivities and possesses the potential to treat/prevent a wide range of human diseases, such as diabetes mellitus, diabetic complications, atherosclerosis, and non-alcoholic fatty liver disease, and the underlying mechanisms were partially elucidated, including mediating signaling pathways like NF-κB, MAPK, PI3K/Akt, apoptotic axis, and Nrf-2/HO-1. This paper presents a review of the natural sources, bioactivities, and the therapeutic/preventive potential of PB2 and the possible mechanisms, with the aim of promoting the development of PB2 as a functional food and providing references for its clinical application in the treatment of diseases.

Anti-Amnesia-like Effect of Pinus densiflora Extract by Improving Apoptosis and Neuroinflammation on Trimethyltin-Induced ICR Mice

This study was conducted to investigate the anti-amnestic property of Korean red pine bark extract (KRPBE) on TMT-induced cognitive decline in ICR mice. As a result of looking at behavioral function, the consumption of KRPBE improved the spatial work ability, short-term learning, and memory ability by Y-maze, passive avoidance, and Morris water maze tests. KRPBE suppressed antioxidant system damage by assessing the SOD activity, reduced GSH content, and MDA levels in brain tissue. In addition, it had a protective effect on cholinergic and synaptic systems by regulating ACh levels, AChE activity, and protein expression levels of ChAT, AChE, SYP, and PSD-95. Also, the KRPBE ameliorated TMT-induced mitochondrial damage by regulating the ROS content, MMP, and ATP levels. Treatment with KRPBE suppressed Aβ accumulation and phosphorylation of tau and reduced the expression level of BAX/BCl-2 ratio and caspase 3, improving oxidative stress-induced apoptosis. Moreover, treatment with KRPBE improved cognitive dysfunction by regulating the neuro-inflammatory protein expression levels of p-JNK, p-Akt, p-IκB-α, COX-2, and IL-1β. Based on these results, the extract of Korean red pine bark, which is discarded as a byproduct of forestry, might be used as an eco-friendly material for functional foods or pharmaceuticals by having an anti-amnesia effect on cognitive impairment.

Proanthocyanidins may be potential therapeutic agents for the treatment of carotid atherosclerosis: A review

Atherosclerotic cerebrovascular disease is one of the major causes of death in China, with associated serious risk of disability and burden on society and families. Therefore, the development of active and effective therapeutic drugs for this disease is of great significance. Proanthocyanidins are a class of naturally occurring active substances, rich in hydroxyl groups and from a wide range of sources. Studies have suggested that they have a strong potential for anti-atherosclerosis activity. In this paper, we review published evidence regarding anti-atherosclerotic effects of proanthocyanidins in different atherosclerotic research models.

Role of Plant-Derived Compounds in the Molecular Pathways Related to Inflammation

Inflammation is the primary response to infection and injury. Its beneficial effect is an immediate resolution of the pathophysiological event. However, sustained production of inflammatory mediators such as reactive oxygen species and cytokines may cause alterations in DNA integrity and lead to malignant cell transformation and cancer. More attention has recently been paid to pyroptosis, which is an inflammatory necrosis that activates inflammasomes and the secretion of cytokines. Taking into consideration that phenolic compounds are widely available in diet and medicinal plants, their role in the prevention and support of the treatment of chronic diseases is apparent. Recently, much attention has been paid to explaining the significance of isolated compounds in the molecular pathways related to inflammation. Therefore, this review aimed to screen reports concerning the molecular mode of action assigned to phenolic compounds. The most representative compounds from the classes of flavonoids, tannins, phenolic acids, and phenolic glycosides were selected for this review. Our attention was focused mainly on nuclear factor-κB (NF-κB), nuclear factor erythroid 2-related factor 2 (Nrf2), and mitogen-activated protein kinase (MAPK) signaling pathways. Literature searching was performed using Scopus, PubMed, and Medline databases. In conclusion, based on the available literature, phenolic compounds regulate NF-κB, Nrf2, and MAPK signaling, which supports their potential role in chronic inflammatory disorders, including osteoarthritis, neurodegenerative diseases, cardiovascular, and pulmonary disorders.

Phytochemicals as potential target on thioredoxin-interacting protein (TXNIP) for the treatment of cardiovascular diseases

Cardiovascular diseases (CVDs) are currently the major cause of death and morbidity on a global scale. Thioredoxin-interacting protein (TXNIP) is a marker related to metabolism, oxidation, and inflammation induced in CVDs. The overexpression of TXNIP is closely related to the occurrence and development of CVDs. Hence, TXNIP inhibition is critical for reducing the overactivation of its downstream signaling pathway and, as a result, myocardial cell damage. Due to the chemical variety of dietary phytochemicals, they have garnered increased interest for CVDs prevention and therapy. Phytochemicals are a source of medicinal compounds for a variety of conditions, which aids in the development of effective and safe TXNIP-targeting medications. The objective of this article is to find and virtual screen novel safe, effective, and economically viable TXNIP inhibitors from flavonoids, phenols, and alkaloids derived from foods and plants. The results of the docking study revealed that silibinin, rutin, luteolin, baicalin, procyanidin B2, hesperetin, icariin, and tilianin in flavonoids, polydatin, resveratrol, and salidroside in phenols, and neferine in alkaloids had the highest Vina scores, indicating that these compounds are the active chemicals on TXNIP. In particular, silibinin can be utilized as a lead chemical in the process of structural alteration. These dietary phytochemicals may aid in the discovery of lead compounds for the development of innovative TXNIP agents for the treatment of cardiovascular disease.

Artificial Infestation of Sarcoptes scabiei (Acari: Sarcoptidae) in Rabbits Exhibits Progressive Pathological Changes, Apoptosis, and Keratinization in the Skin

Sarcoptes scabiei (S. scabiei) is an ectoparasite that can infest humans and 150 mammalian host species, primarily causing pruritus, crust, and alopecia. However, neither the pathological process of host skin under S. scabiei infection nor the mechanism of S. scabiei infection in regulating apoptosis and keratinization of host skin has been studied yet. In this study, a total of 56 rabbits were artificially infested with S. scabiei, and the skin samples were collected at seven different time points, including 6 h, 12 h, day 1, day 3, 1 week, 4 weeks, and 8 weeks, whereas a group of eight rabbits served as controls. We measured epidermal thickness by H&E staining, observed the skin ultrastructure by electron microscopy, and detected the degree of skin apoptosis by TUNEL staining. The level of transcription of genes related to apoptosis and keratinization was detected by quantitative real-time PCR (qRT-PCR), and the level of Bcl-2 protein expression was further detected using immunohistochemistry. Our results showed that, with increased infestation time, the epidermal layer of the rabbit skin exhibited significant thickening and keratinization, swollen mitochondria in the epidermal cells, and increased skin apoptosis. The level of caspase-1, 3, 8, 10, 14, and Bcl-2 mRNA expression was increased, whereas the level of keratin 1 and 5 was decreased after S. scabiei infestation. In conclusion, S. scabiei infestation causes thickening of the epidermis, which may be related to apoptosis-induced proliferation and skin keratinization.

Bioactivities and mechanisms of dietary proanthocyanidins on blood pressure lowering: A critical review of in vivo and clinical studies

Proanthocyanidins, widespread in natural plant sources, are bioactive substances that exhibit broad benefits to human health. Of note, proanthocyanidins have been reported to lower blood pressure and prevent hypertension, but a critical review of this is lacking. In this review, information on the basic structures and absorption of dietary proanthocyanidins as well as their bioactivities and related mechanisms on the lowering of blood pressure derived via in vivo and clinical studies are summarized. Clinical studies have shown that proanthocyanidins have a pronounced blood pressure-lowering effect, effectively preventing hypertension and reducing the occurrence of cardiovascular and cerebrovascular diseases. The potential mechanisms, which are herein reviewed in detail, involve the improvement of vascular function, reduction of oxidative stress and inflammation, and modulation of lipid metabolism. Taken together, this work provides information for a better understanding of the antihypertensive effects of proanthocyanidins, which may promote their use to reduce the risk of developing hypertension.

Beneficial effects of procyanidin B2 on adriamycin-induced nephrotic syndrome mice: the multi-action mechanism for ameliorating glomerular permselectivity injury

Despite considerable advances in prevention, diagnosis, and therapy, nephrotic syndrome (NS) remains a significant cause of high morbidity and mortality globally. As a result, there is an urgent need to identify novel effective preventative and therapeutic agents for NS. NS is implicated in glomerular permselectivity injury, which can be attributed to oxidative distress, inflammation, lipid nephrotoxicity, podocyte apoptosis, autophagy dysfunction, and slit diaphragm (SLD) dysfunction. In addition to its well-documented antioxidant potency, procyanidin B2 (PB2) may exhibit pleiotropic effects by targeting various canonical signaling events, such as NF-κB, PPARs, PI3K/Akt, mTOR, and the caspase family. As a result, PB2 may be a promising therapeutic target against NS. To test this hypothesis, we established an Adriamycin (ADR)-induced NS mouse model to evaluate the pleiotropic renoprotective effects of PB2 on NS. Here, we demonstrated that PB2 improves podocyte injury via inhibition of NOX4/ROS and Hsp90/NF-κB to exhibit antioxidant and anti-inflammatory potency, respectively. We also show that PB2 indirectly activates the PI3K/Akt axis by regulating SLD protein levels, resulting in normalized podocyte apoptosis and autophagy function. Further, loss of albumin (ALB) induces lipid nephrotoxicity, which we found to be alleviated by PB2 via activation of PPARα/β-mediated lipid homeostasis and the cholesterol efflux axis. Interestingly, our results also suggested that PB2 reduces electrolyte abnormalities and edema. In addition, PB2 may contribute protective effects against trace element dys-homeostasis, which, through alleviating serum ALB loss, leads to a protective effect on glomerular permselectivity injury. Taken together, our results reveal that the identified mechanisms of PB2 on NS are multifactorial and involve inhibition of oxidative distress and inflammatory responses, as well as improvements in podocyte apoptosis and autophagy dysfunction, amelioration of lipid nephrotoxicity, and modulation of electrolyte abnormalities and edema. Thus, we provide a theoretical basis for the clinical application of PB2 against NS.

Procyanidin B2 Alleviates Heat-Induced Oxidative Stress through the Nrf2 Pathway in Bovine Mammary Epithelial Cells

The objective of this study was to investigate the protective effects and potential molecular mechanisms of procyanidin B2 (PB2) in MAC-T (mammary alveolar cells-large T antigen) cells during heat stress (HS). The MAC-T cells were divided into three treatment groups: control (37 °C), HS (42 °C), and PB2 + HS (42 °C). Compared with MAC-T cells that were consistently cultured at 37 °C, acute HS treatment remarkably decreased cell viability, reduced activities of catalase (CAT), superoxide dismutase (SOD), and total antioxidant capacity (T-AOC), and elevated intracellular levels of malondialdehyde (MDA) and reactive oxygen species (ROS). Additionally, nuclear factor erythroid 2-related factor 2 (Nrf2) was activated and translocated to the nucleus, in accompaniment with upregulation of Nrf2, heme oxygenase 1 (HO-1), thioredoxin reductase 1 (Txnrd1), and heat shock protein 70 (HSP70). In parallel, both mRNA transcript and actual protein secretion of pro-inflammatory cytokines, including tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β), were increased by heat stress. Pretreatment of MAC-T cells with 0~25 μM PB2 alleviated the decline of cell viability by HS in a dose-dependent fashion and protected cells against HS-induced oxidative stress, as evidenced by significantly improved CAT, SOD, and T-AOC activity, as well as with decreased MDA and ROS generation. Furthermore, PB2 further activated the Nrf2 signaling pathway and reversed the inflammatory response induced by HS. Silencing of Nrf2 by si-Nrf2 transfection not only exacerbated HS-induced cell death and provoked oxidative stress and the inflammatory response, but also greatly abolished the cytoprotective effects under HS of PB2. In summary, PB2 protected MAC-T cells against HS-induced cell death, oxidative stress, and inflammatory response, partially by operating at the Nrf2 signal pathway.