Effect of Sanguis draconis (a dragon's blood resin) on streptozotocin- and cytokine-induced β-cell damage, in vitro and in vivo

Repair Effect of Umbilical Cord Mesenchymal Stem Cells Embedded in Hydrogel on Mouse Insulinoma 6 Cells Injured by Streptozotocin

Umbilical cord mesenchymal stem cells (UC-MSCs) possess the capabilities of differentiation and immune modulation, which endow them with therapeutic potential in the treatment of type 2 diabetes mellitus (T2DM). In this study, to investigate the repair mechanism of UC-MSCs in hydrogel on pancreatic β-cells in diabetes, mouse insulinoma 6 (MIN-6) cells damaged by streptozotocin (STZ) in vitro were used in co-culture with UC-MSCs in hydrogel (UC-MSCs + hydrogel). It was found that UC-MSCs + hydrogel had a significant repair effect on injured MIN-6 cells, which was better than the use of UC-MSCs alone (without hydrogel). After repair, the expression of superoxide dismutase (SOD) and catalase (CAT) as well as the total antioxidant capacity (T-AOC) of the repaired MIN-6 cells were increased, effectively reducing the oxidative stress caused by STZ. In addition, UC-MSCs + hydrogel were able to curb the inflammatory response by promoting the expression of anti-inflammatory factor IL-10 and reducing inflammatory factor IL-1β. In addition, the expression of both nuclear antigen Ki67 for cell proliferation and insulin-related genes such as Pdx1 and MafA was increased in the repaired MIN-6 cells by UC-MSCs + hydrogel, suggesting that the repair effect promotes the proliferation of the injured MIN-6 cells. Compared with the use of UC-MSCs alone, UC-MSCs + hydrogel exhibit superior antioxidant stress resistance against injured MIN-6 cells, better proliferation effects and a longer survival time of UC-MSCs because the porous structure and hydrophilic properties of the hydrogel could affect the growth of cells and slow down their metabolic activities, resulting in a better repair effect on the injured MIN-6 cells.

Soluble polyvinylpyrrolidone-based microneedles loaded with Sanguis draconis and Salvia miltiorrhiza for treatment of diabetic wound healing

BACKGROUND

Nowadays, diabetic wound healing remains a crucial challenge due to their protracted and uncertain healing process. Traditional Chinese medicine (TCM) has demonstrated the therapeutic value of Sanguis draconis (SD)-Salvia miltiorrhiza (SMR) Herb Pair in diabetic wound healing. However, new administration modes are urgently needed for their convenient and wide-ranging applications.

OBJECTIVE

We propose a soluble polyvinylpyrrolidone-based microneedle patch containing the herbal extracts of SD and SMR (MN-SD@SMR) for diabetic wound healing.

METHODS

The herbal extracts of SD and SMR are purification and concentration via traditional lyophilization. SD endowed MN-SD@SMR with functions to improve high glycemic blood environment and migration of keratinocyte and fibroblast cells.

RESULTS

SMR in MN-SD@SMR could improve blood flow velocity and microcirculation in the wound area. The effectiveness of transdermal release and mechanical strengths of MN-SD@SMR were verified.

CONCLUSION

Integrating the advantages of these purified herbal compositions, we demonstrated that MN-SD@SMR had a positive healing effect on the wounds in vitro and vivo. These results indicate that soluble polyvinylpyrrolidone-based microneedle patch containing the herbal extracts of SD and SMR has a promising application value due to their superior capability to promote diabetic wound healing.

Isolated compounds from Dracaena angustifolia Roxb and acarbose synergistically/additively inhibit α-glucosidase and α-amylase: an in vitro study

Background

As a traditional herbal medicine, Dracaena angustifolia Roxb has been used as an anti-inflammatory agent by the Li people in Hainan, China. In preliminary phytochemical studies conducted in our lab, its fractions were found to inhibit α-glucosidase in vitro, indicating a potential for alleviating glucose dysregulation.

Methods

Through in vitro enzymatic assays, the abilities of the separated components to affect α-glucosidase and α-amylase were evaluated. By establishing concentration gradients and generating Lineweaver–Burk plots, the corresponding inhibition modes together with kinetic parameters were assessed. Following the evaluation of the outcomes of their combination with acarbose, computational docking and molecular dynamic simulations were carried out to analyse the interaction mechanisms and perform virtual screening against human enzymes.

Results

Compared with acarbose, 7 compounds, including flavonoid derivatives, amides and aromatic derivatives, with higher α-glucosidase inhibitory efficiencies were confirmed. It was found that those competitive/mixed candidates and acarbose interacted synergistically or additively on α-glucosidase. Moreover, 3 of them were able to inhibit α-amylase in mixed mode, and additive effects were observed in combination with acarbose. Through in silico docking, it was found that the active site residues as well as adjacent residues were involved in α-glucosidase and α-amylase binding, which were mainly achieved through hydrogen bonding. Among those dual-function flavonoids, Compound 9 was predicted to be a considerable inhibitor of human enzymes, as the formation of ligand–enzyme complexes was mediated by the residues responsible for substrate recognition and catalysis, the stabilities of which were reiterated by molecular dynamics simulations.

Conclusion

Despite their mild effects on α-amylase, considerable α-glucosidase inhibitory efficiencies and potential synergy with acarbose were exhibited by these natural candidates. Furthermore, a stable ligand, human α-glucosidase, was predicted by the performed simulations, which provided useful information for the application of Dracaena angustifolia Roxb in diabetes treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-022-03649-3.

Loureirin B activates GLP-1R and promotes insulin secretion in Ins-1 cells

Loureirin B (LB) is a natural product derived from Sanguis draconis, which has hypoglycaemic effects. In order to research the possible target of LB in the treatment of diabetes, molecular docking was used to simulate the interaction between LB and potential targets, and among them, glucagon‐like peptide‐1 receptor (GLP‐1R) had the optimal results. Further, spectroscopy and surface plasmon resonance (SPR) experiments were applied to detect the interaction between LB and GLP‐1R. Ultimately, after GLP‐1R siRNA interfering the expression of GLP‐1R in Ins‐1 cell, the promoting insulin secretion of LB was weaken, which directly proved that GLP‐1R plays an important role. These results show that LB promotes insulin secretion of Ins‐1 cells through GLP‐1R. Hence, the strategy of LB as a prodrug will provide a potential approach for non‐peptide GLP‐1R agonist.

Jixuepaidu Tang-1 inhibits epithelial-mesenchymal transition and alleviates renal damage in DN mice through suppressing long non-coding RNA LOC498759

Jixuepaidu Tang-1 is obtained from the decoction of the Chinese traditional medicinal plants including Centella asiatica, Astragalus membranaceus, and Sanguis draconis. Transforming growth factor-β1 (TGF-β1)/serum- and glucocorticoid-inducible kinase-1 (SGK1)-induced epithelial-mesenchymal transition (EMT) plays a pivotal role in the pathogenesis of diabetic nephropathy (DN). In addition, long non-coding RNAs (lnRNAs) participate in the development of DN, but the role of lncRNA LOC498759 in DN is still unclear. This study aims to investigate the role of Jixuepaidu Tang-1 in regulating podocyte injury and renal damage in DN and to validate whether the mechanisms involve TGF-β1/SGK1 signaling and LOC498759. The drug treatment was initiated 2 weeks after the DN modeling. The MTT method and TUNEL staining were used to measure cell viability and apoptosis, respectively. Immunofluorescence staining was used to detect the expression of nephrin and desmin in podocytes. Sera from the Jixuepaidu Tang-1-treated mice reversed the high glucose (HG)-induced podocyte injury and EMT in mouse podocytes. Further in vivo assay revealed that Jixuepaidu Tang-1 not only reduced the ratio of the kidney to body weight, 24 h-urine total protein, and blood glucose, but alleviated glomerular mesangial extracellular matrix deposition and glomerular cell apoptosis in the streptozotocin-induced DN mice. Mechanically, the mechanisms of Jixuepaidu Tang-1 may involve the suppression of EMT by inhibiting the TGF-β1/SGK1-induced LOC498759 expression. Collectively, Jixuepaidu Tang-1 attenuates podocyte injury and renal damage in DN, and inhibits EMT through suppressing TGF-β1/SGK1-LOC498759 signaling.

Streptozotocin-Induced Autophagy Reduces Intracellular Insulin in Insulinoma INS-1E Cells

Streptozotocin (STZ), a glucose analog, induces diabetes in experimental animals by inducing preferential cytotoxicity in pancreatic beta cells. We investigated whether STZ reduced the production of intracellular insulin through autophagy in insulinoma INS-1E cells. Typically, 2 mM STZ treatment for 24 h significantly decreased cell survival. STZ treatment led to significant decrease in phospho-AMP-activated protein kinase (p-AMPK) level; reduction in levels of phospho-protein kinase R-like endoplasmic reticulum kinase (PERK) and inositol-requiring enzyme 1α (IRE1α); significant reduction in levels of p85α, p110, phospho-serine and threonine kinase/protein kinase B (p-Akt/PKB) (Ser473), phospho-extracellular-regulated kinase (p-ERK), and phospho-mammalian target of rapamycin (p-mTOR); increase in levels of Cu/Zn-superoxide dismutase (SOD), Mn-SOD, and catalase; decrease in B-cell lymphoma 2 (Bcl-2) expression; increase in Bcl-2-associated X protein (Bax) expression; increase in levels of microtubule-associated protein 1 light chain 3 (LC3) and Beclin 1; and reduction in production of intracellular insulin. These results suggest that insulin synthesis during STZ treatment involves autophagy in INS-1E cells and, subsequently, results in a decrease in intracellular production of insulin.

Cochinchinenin C, a potential nonpolypeptide anti-diabetic drug, targets a glucagon-like peptide-1 receptor

The glucagon-like peptide-1 (GLP-1) receptor is currently being explored as a therapeutic target for anti-diabetic drugs.

Effects of Sanguis Draconis on Perforator Flap Survival in Rats

Sanguis draconis, a resin known to improve blood circulation, relieve pain, stimulate tissue regeneration, and heal wounds, is widely used in clinical practice. In this study, we prepared an ethanol extract of sanguis draconis (EESD) containing 75.08 mg/g of dracorhodin. The experiment was carried out on 20 rats that were divided into two groups, a control group (n = 10) and an EESD group (n = 10). All the rats underwent a perforator flap surgery, after which post-operative abdominal compressions of EESD were given to the EESD group for seven days, while the control group received saline. Flap survival percentages were determined after seven days, and were found to be significantly higher in the EESD group than in the control group. Results of laser Doppler flowmetry (LDF) showed that perforator flaps in the EESD group had higher perfusion values than those of the control group. The flap tissues were stained with hematoxylin and eosin, followed by immunohistochemical evaluation. Superoxide dismutase (SOD) expression and micro-vessel development markedly increased in the EESD group, while malondialdehyde (MDA) levels decreased. This is the first study to investigate the effect of sanguis draconis on perforator flap survival. Our results demonstrate that sanguis draconis can improve perforator flap survival in rats by promoting microvessel regeneration and blood perfusion.

Ancient records and modern research on the mechanisms of chinese herbal medicines in the treatment of diabetes mellitus

Over the past decades, Chinese herbal medicines (CHM) have been extensively and intensively studied through from both clinical and experimental perspectives and CHM have been proved to be effective in the treatment of diabetes mellitus (DM). This study, by searching ancient records and modern research papers, reviewed CHM in terms of their clinical application and principal mechanism in the treatment of DM. We summarized the use of CHM mentioned in 54 famous ancient materia medica monographs and searched papers on the hypoglycemic effect of several representative CHM. Main mechanisms and limitations of CHM and further research direction for DM were discussed. On the basis of the study, we were led to conclude that TCM, as a main form of complementary and alternative medicine (CAM), was well recorded in ancient literatures and has less adverse effects as shown by modern studies. The mechanisms of CHM treatment of DM are complex, multilink, and multitarget, so we should find main hypoglycemic mechanism through doing research on CHM monomer active constituents. Many CHM monomer constituents possess noteworthy hypoglycemic effects. Therefore, developing a novel natural product for DM and its complications is of much significance. It is strongly significant to pay close attention to CHM for treatment of DM and its complications.

Loureirin B, an essential component of Sanguis Draxonis, inhibits Kv1.3 channel and suppresses cytokine release from Jurkat T cells

Sanguis draxonis (SD), also known as “Dragon’s Blood”, is a traditional herb medicine that has been used to treat a variety of complications with unknown mechanisms. Recent studies show that SD displays immunosuppressive activities and improves symptoms of type I diabetes in animal models. However, the mechanisms underlying SD’s immunosuppressive actions are not completely understood. The voltage-gated Kv1.3 channel plays a critical role in the pathogenesis of autoimmune diseases by regulating the functions of both T cells and B cells. Here we investigated the effect of SD and one of its active components loureirin B (LrB) on Kv1.3. Both SD and LrB inhibited Kv1.3-mediated currents, produced a membrane depolarization, and reduced Ca²⁺ influx in Jurkat T cells. In addition, application of LrB inhibited phytohemagglutinin (PHA)-induced IL-2 release from activated Jurkat T cells. Furthermore, point mutations in the selective filter region significantly reduced the inhibitory effect of LrB on Kv1.3. The results of these experiments provide evidence that LrB is a channel blocker of Kv1.3 by interacting with amino acid residues in its selective filter region. Direct inhibition of Kv1.3 in T cells by SD and LrB might be the cellular and molecular basis of SD-mediated immunosuppression.

Sanguis draconis, a dragon's blood resin, attenuates high glucose-induced oxidative stress and endothelial dysfunction in human umbilical vein endothelial cells

Hyperglycaemia, a characteristic feature of diabetes mellitus, induces endothelial dysfunction and vascular complications by limiting the proliferative potential of these cells. Here we aimed to investigate the effect of an ethanolic extract of Sanguis draconis (SD), a kind of dragon's blood resin that is obtained from Daemonorops draco (Palmae), on human umbilical vein endothelial cells (HUVEC) under high-glucose (HG) stimulation and its underlying mechanism. Concentration-dependent (0-50 μg/mL) assessment of cell viability showed that SD does not affect cell viability with a similar trend up to 48 h. Remarkably, SD (10-50 μg/mL) significantly attenuated the high-glucose (25 and 50 mM) induced cell toxicity in a concentration-dependent manner. SD inhibited high glucose-induced nitrite (NO) and lipid peroxidation (MDA) production and reactive oxygen species (ROS) formation in HUVEC. Western blot analysis revealed that SD treatments abolished HG-induced phosphorylation of extracellular signal-regulated kinase 1/2 (ERK 1/2), nuclear transcription factor, κB (NF-κB), VCAM-1, and E-selectin, and it also blocked the breakdown of PARP-116 kDa protein in a dose-dependent manner. Furthermore, we found that SD increased the expression of Bcl-2 and decreased Bax protein expression in HG-stimulated HUVEC. Thus, these results of this study demonstrate for the first time that SD inhibits glucose induced oxidative stress and vascular inflammation in HUVEC by inhibiting the ERK/NF-κB/PARP-1/Bax signaling cascade followed by suppressing the activation of VCAM-1 and E-selectin. These data suggest that SD may have a therapeutic potential in vascular inflammation due to the decreased levels of oxidative stress, apoptosis, and PARP-1 activation.

Anti-inflammatory therapy in type 1 diabetes

Type 1 diabetes (T1D) is a multi-factorial, organ-specific autoimmune disease in genetically susceptible individuals, which is characterized by a selective and progressive loss of insulin-producing β-cells. Cells mediating innate as well as adaptive immunity infiltrate pancreatic islets, thereby generating an aberrant inflammatory process called insulitis that can be mirrored by a pathologic autoantibody production and autoreactive T-cells. In tight cooperation with infiltrating innate immune cells, which secrete high levels of pro-inflammatory cytokines like IL-1β, TNFα, and INFγ effector T-cells trigger the fatal destruction process of β-cells. There is ongoing discussion on the contribution of inflammation in T1D pathogenesis, ranging from a bystander reaction of autoimmunity to a dysregulation of immune responses that initiate inflammatory processes and thereby actively promoting β-cell death. Here, we review recent advances in anti-inflammatory interventions in T1D animal models and preclinical studies and discuss their mode of action as well as their capacity to interfere with T1D development.

Protective effect of guggulsterone against cardiomyocyte injury induced by doxorubicin in vitro

BACKGROUND

Doxorubicin (DOX) is an effective antineoplastic drug; however, clinical use of DOX is limited by its dose-dependent cardiotoxicity. It is well known that reactive oxygen species (ROS) play a vital role in the pathological process of DOX-induced cardiotoxicity. For this study, we evaluated the protective effects of guggulsterone (GS), a steroid obtained from myrrh, to determine its preliminary mechanisms in defending against DOX-induced cytotoxicity in H9C2 cells.

METHODS

In this study, we used a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay, lactate dehydrogenase (LDH) release measurements, and Hoechst 33258 staining to evaluate the protective effect of GS against DOX-induced cytotoxicity in H9C2 cells. In addition, we observed the immunofluorescence of intracellular ROS and measured lipid peroxidation, caspase-3 activity, and apoptosis-related proteins by using Western blotting.

RESULTS

The MTT assay and LDH release showed that treatment using GS (1-30 μM) did not cause cytotoxicity. Furthermore, GS inhibited DOX (1 μM)-induced cytotoxicity in a concentration-dependent manner. Hoechst 33258 staining showed that GS significantly reduced DOX-induced apoptosis and cell death. Using GS at a dose of 10-30 μM significantly reduced intracellular ROS and the formation of MDA in the supernatant of DOX-treated H9C2 cells and suppressed caspase-3 activity to reference levels. In immunoblot analysis, pretreatment using GS significantly reversed DOX-induced decrease of PARP, caspase-3 and bcl-2, and increase of bax, cytochrome C release, cleaved-PARP and cleaved-caspase-3. In addition, the properties of DOX-induced cancer cell (DLD-1 cells) death did not interfere when combined GS and DOX.

CONCLUSION

These data provide considerable evidence that GS could serve as a novel cardioprotective agent against DOX-induced cardiotoxicity.