Effects of rhubarb on the expression of glucocorticoids receptor and regulation of cellular immunity in burn-induced septic rats

Scorch processing of rhubarb (Rheum tanguticum Maxim. ex Balf.) pyrolyzed anthraquinone glucosides into aglycones and improved the therapeutic effects on thromboinflammation via regulating the complement and coagulation cascades pathway

ETHNOPHARMACOLOGICAL RELEVANCE

The pathophysiological mechanism of thromboinflammation involves the intricate interplay between the inflammatory responses and coagulation cascades. Rhubarb is frequently used in traditional Chinese medicine to treat thromboinflammatory diseases. The scorched rhubarb (prepared by stir-baking the dried raw rhubarb till it partly turns to charcoal) is believed to possess enhanced blood-cooling and stasis-removing functions compared to the raw rhubarb, thereby augmenting the therapeutic effects on thromboinflammation.

AIM OF THE STUDY

This study aimed to explore the chemical and pharmacological foundations of the scorch processing of rhubarb in order to ensure and enhance the efficacy and safety of the scorched rhubarb for treating thromboinflammatory diseases.

MATERIALS AND METHODS

The dried raw rhubarb pieces were subjected to stir-baking at 180 °C for 10∼80 min to obtain the rhubarbs with varying degrees of scorching. Typical ingredients present in rhubarb pieces and extracts were determined by high-performance liquid chromatography. The therapeutic effects of the raw and scorched rhubarb on thromboinflammation were evaluated using a rat model. Proteomics analysis was employed to screen potential biological pathways associated with thromboinflammation treatment by the raw and scorched rhubarb, which were further verified using a cell model.

RESULTS

Morphological properties indicated that the rhubarb baked at 180 °C for 50 min in this research showed the optimal degree of scorching. Compared to the raw rhubarb, the properly scorched rhubarb exhibited lower levels of anthraquinone glucosides, higher levels of anthraquinone aglycones, superior anti-thromboinflammatory effects, and no purgative side effects. Proteomics analysis revealed that the complement and coagulation cascades pathway played a significant role in mediating the therapeutic effects of the raw and scorched rhubarb on thromboinflammation. Furthermore, it was found that anthraquinone aglycones were more effective than their glucoside counterparts in restoring the impaired vascular endothelial cells as well as regulating the complement and coagulation cascades pathway.

CONCLUSIONS

Proper scorch processing may augment the therapeutic effects of rhubarb on thromboinflammation via relieving inflammation and oxidative stress, repairing vascular endothelial cells, restoring coagulation cascades and blood rheology, and regulating some other biological processes. This may be partly caused by the scorch-induced thermolysis of anthraquinone glucosides into their aglycone counterparts that seemed to perform better in regulating the complement and coagulation cascades pathway.

Chrysophanol, a main anthraquinone from Rheum palmatum L. (rhubarb), protects against renal fibrosis by suppressing NKD2/NF-κB pathway

PURPOSE

Chronic kidney disease (CKD), characterized as renal dysfunction and multi-system damage, has become a serious public health problem with high prevalence and mortality. Rheum palmatum L. (rhubarb) is one of the most widely used Chinese herb with renal protective activity. However, the active components and underlying mechanisms of rhubarb remain unknown. In this work, we tried to explore the pharmacological mechanism of chrysophanol, a main anthraquinone from rhubarb, against CKD by in vivo and in vitro models.

STUDY DESIGN

The therapeutic effect of chrysophanol and its underlying mechanism were investigated using CKD mouse model induced by unilateral ureteral occlusion (UUO), and human kidney 2 (HK-2) cells stimulated by TGF-β1 in vivo.

METHODS

The impact of chrysophanol on renal function, inflammation, fibrosis of CKD mice were evaluated. Then, the protein expressions of FN1, collagen ɑI, α-SMA, NF-κB and naked keratinocyte homolog 2 (NKD2) were investigated. In vitro studies, the inhibition on inflammation and fibrogenesis by chrysophanol was further validated in TGF-β1-stimulated HK2 cells, and the regulation of chrysophanol on NKD2/NF-κB pathway was analyzed. Moreover, NKD2 was overexpressed in HK-2 cells to confirm the role of NKD2/NF-κB pathway in chrysophanol-mediated efficacy. Finally, the binding mode of chrysophanol with NKD2 was studied using in silico molecular docking and microscale thermophoresis (MST) assay.

RESULTS

Chrysophanol could significantly improve the kidney dysfunction, alleviate renal pathology, and reverse the elevated levels of renal fibrosis markers such as FN1, collagen ɑI and α-SMA. Furthermore, chrysophanol effectively inhibited TNF-α, IL-6, and IL-1β production, and suppressed NF-κB activation and NKD2 expression. The findings of in vitro study were consistent with those of animal expriment. Using NKD2-overexpressing HK-2 cells, we also demonstrated that overexpression of NKD2 significantly compromised the anti-fibrotic effects of chrysophanol. In addition, molecular docking and MST analysis revealed that NKD2 was a direct target of chrysophanol.

CONCLUSION

Together, our work demonstrated for the first time that chrysophanol could effectively ameliorate renal fibrosis by inhibiting NKD2/NF-κB pathway. Chrysophanol can potentially prevent CKD by suppressing renal NKD2 expression directly.

Network Pharmacology Experiments Show That Emodin Can Exert a Protective Effect on MCAO Rats by Regulating Hif-1α/VEGF-A Signaling

Modern pharmacological studies have shown that emodin, the main effective component of rhubarb, has good anti-inflammatory and antioxidant effects, but its pharmacodynamic mechanism remains unclear yet. This study aims to elucidate the multitarget action mechanism of emodin in ischemic stroke through network pharmacology and in vivo experiments. Sprague-Dawley rats were randomly divided into control (normal saline), sham (normal saline), model (normal saline), and emodin groups (n = 9 per group). Emodin was administered at 40 mg/kg/d for 3 consecutive days. The rats were subjected to middle cerebral artery occlusion for 2 h, followed by reperfusion for 24 h to establish the cerebral ischemia-reperfusion injury. To search for relevant studies in databases, emodin, ischemic stroke, and stroke were used as keywords. Subsequently, protein-protein interaction networks and complex disease target networks were established, and an enrichment analysis and molecular docking of core targets were performed. Gene expression was detected through western blotting and reverse-transcription polymerase chain reaction. Localization and expression of proteins were detected through immunohistochemistry. Furthermore, the neurological function, 2,3,5-triphenyltetrazolium chloride staining, levels of brain tissue inflammatory factors, the role of the blood-brain barrier (BBB), and relevant signaling pathways were assessed in vivo. The molecular docking of core targets revealed that the docking between vascular endothelial growth factor A (VEGF-A) and emodin was the most efficient. Emodin pretreatment decreased the neurological score from 2.875 to 1.125. Moreover, emodin inhibited the degradation of occludin and claudin-5 caused by matrix metalloprotein kinase (MMP)-2/MMP-9, thereby protecting the BBB. Additionally, related proteins such as hypoxia-inducible factor-1α/VEGF-A and nuclear factor kappa B were down-regulated. Thus, emodin may play a protective role during cerebral ischemia reperfusion through mediation of the Hif-1α/VEGF-A signaling pathway to inhibit the expression of inflammatory factors.

Regulatory T Cells: Angels or Demons in the Pathophysiology of Sepsis?

Sepsis is a syndrome characterized by life-threatening organ dysfunction caused by the dysregulated host response to an infection. Sepsis, especially septic shock and multiple organ dysfunction is a medical emergency associated with high morbidity, high mortality, and prolonged after-effects. Over the past 20 years, regulatory T cells (Tregs) have been a key topic of focus in all stages of sepsis research. Tregs play a controversial role in sepsis based on their heterogeneous characteristics, complex organ/tissue-specific patterns in the host, the multi-dimensional heterogeneous syndrome of sepsis, the different types of pathogenic microbiology, and even different types of laboratory research models and clinical research methods. In the context of sepsis, Tregs may be considered both angels and demons. We propose that the symptoms and signs of sepsis can be attenuated by regulating Tregs. This review summarizes the controversial roles and Treg checkpoints in sepsis.

Antimicrobial and Immunomodulatory Activity of Herb Extracts Used in Burn Wound Healing: "San Huang Powder"

"San Huang Powder," a nonsterile milled herb powder, is frequently used to treat burn wounds in traditional Chinese herbal medicine. However, treating a wound with a nonsterile dressing or reagent is not compatible with the current guidelines in modern medicine. Therefore, we investigated the bactericidal and anti-inflammatory activities of four herb extracts used in "San Huang Powder" in vitro. Meanwhile, an in vivo porcine model with superficial second-degree burns was used for the experiments since the size and skin composition of pigs are the closest to that of the human body. The minimal bactericidal concentration (MBC) of the herb extracts was determined. The in vitro assay indicated that Rhubarb and Phellodendron bark extracts decreased the levels of inflammatory cytokines, IL-8, and GM-CSF on LPS-induced HMEC-1 cells. In accordance with this result, the histopathological evaluation results showed that the efficacy of "San Huang Powder" containing both herb materials was much better than the group without Rhubarb. Our results not only provide a basis to understand why "San Huang Powder" has been used to clinically treat wounds without sterilization directly since ancient times but also show the advantages of using multiple herb materials simultaneously on wound sites to prevent infection during treatment. Rhubarb is the recommended ingredient involved in the preparation of "San Huang Powder" to ensure the healing efficacy of burn wounds.