Magnesium alleviates extracellular histone-induced apoptosis and defective bacterial phagocytosis in macrophages by regulating intracellular calcium signal.

Extracellular histones have been determined as important mediators of sepsis, which induce excessive inflammatory responses in macrophages and impair innate immunity. Magnesium (Mg2+), one of the essential nutrients of the human body, contributes to the proper regulation of immune function. However, no reports indicate whether extracellular histones affect survival and bacterial phagocytosis in macrophages and whether Mg2+ is protective against histone-induced macrophage damage. Our clinical data revealed a negative correlation between circulating histone and monocyte levels in septic patients, and in vitro experiments confirmed that histones induced mitochondria-associated apoptosis and defective bacterial phagocytosis in macrophages. Interestingly, our clinical data also indicated an association between lower serum Mg2+ levels and reduced monocyte levels in septic patients. Moreover, in vitro experiments demonstrated that Mg2+ attenuated histone-induced apoptosis and defective bacterial phagocytosis in macrophages through the PLC/IP3R/STIM-mediated calcium signaling pathway. Importantly, further animal experiments proved that Mg2+ significantly improved survival and attenuated histone-mediated lung injury and macrophage damage in histone-stimulated mice. Additionally, in a cecal ligation and puncture (CLP) + histone-induced injury mouse model, Mg2+ inhibited histone-mediated apoptosis and defective phagocytosis in macrophages and further reduced bacterial load. Overall, these results suggest that Mg2+ supplementation may be a promising treatment for extracellular histone-mediated macrophage damage in sepsis.

Tougu Xiaotong capsule exerts a therapeutic effect on knee osteoarthritis by regulating subchondral bone remodeling.

Previous studies have shown that Tougu Xiaotong capsule (TGXTC) has therapeutic effects on knee osteoarthritis (OA) through multiple targets. However, the mechanisms of action underlying its regulation of subchondral bone reconstruction remain unclear. In this study, we investigated the effects of TGXTC on subchondral bone remodeling. Eighteen six-month-old New Zealand white rabbits of average sex were randomly divided into the normal, model and TGXTC groups. The rabbit knee OA model was induced by a modified Hulth's method in the model and TGXTC groups, but not the normal group. Five weeks postoperatively, intragastric administration of TGXTC was performed for four weeks. After drug administration, the medial femoral condyle and tibia were prepared for observation of cartilage histology via optical microscopy and micro-computed tomography, the serum was collected for biochemical parameters assay and the subchondral bone isolated from the lateral femoral condyle was collected for detection of IL-1ß and TNF-α mRNA and protein by reverse transcription-quantitative polymerase chain reaction and western blot analysis, respectively. The results showed that treatment with TGXTC significantly mitigated cartilage injury and subchondral bone damage, improved the parameter of subchondral trabecular bone, decreased alkaline phosphatase and tartrate-resistant acid phosphatase activity, and significantly reducing the osteoprotegerin/receptor activator of nuclear factor-κB ligand ratio, reduced the expression of IL-1ß and TNF-α mRNA and protein. These results suggest that TGXTC could delay the pathological development of OA by regulating subchondral bone remodeling through regulation of bone formation and bone resorption and its relating inflammatory factors, and this may partly explain its clinical efficacy in the treatment of knee OA.

Cross-Linked Pectin Nanofibers with Enhanced Cell Adhesion.

Polysaccharides display poor cell adhesion due to the lack of cell binding domains. This severely limits their applications in regenerative medicine. This study reports novel cross-linked pectin nanofibers with dramatically enhanced cell adhesion. The nanofibers are prepared by at first oxidizing pectin with periodate to generate aldehyde groups and then cross-linking the nanofibers with adipic acid dihydrazide to covalently connect pectin macromolecular chains with adipic acid dihydrazone linkers. The linkers may act as cell binding domains. Compared with traditional Ca2+-cross-linked pectin nanofibers, the pectin nanofibers with high oxidation/cross-linking degree exhibit much enhanced cell adhesion capability. Moreover, the cross-linked pectin nanofibers exhibit excellent mechanical strength (with Young's modulus ∼10 MPa) and much enhanced body degradability (degrade completely in 3 weeks or longer time). The combination of excellent cell adhesion capability, mechanical strength, and body degradability suggests that the cross-linked pectin nanofibers are promising candidates for in vivo applications such as tissue engineering and wound healing. This cross-linking strategy may also be used to improve the cell adhesion capability of other polysaccharide materials.

Effect of Gelsemium elegans and Mussaenda pubescens, the Components of a Detoxification Herbal Formula, on Disturbance of the Intestinal Absorptions of Indole Alkaloids in Caco-2 Cells.

Gelsemium elegans (GE) is a kind of well-known toxic plant. It can be detoxified by Mussaenda pubescens (MP), but the detoxification mechanism is still unclear. Thus, a detoxification herbal formula (GM) comprising GE and MP was derived. The Caco-2 cells monolayer model was used to evaluate GM effects on transporting six kinds of indole alkaloids of GE. The bidirectional transport studies demonstrated that absorbance percentage of indole alkaloids in GE increased linearly over time. But in GM, Papp (AP→BL) values of the most toxic members, gelsenicine, humantenidine, and gelsevirine, were lower than that of Papp (BL→AP) (P < 0.05). The prominent analgesic effect members, gelsemine and koumine, were approximately 1.00 in γ values. Nowhere was this increasing efflux more pronounced than in the case of indole alkaloids with N-O structure. In the presence of verapamil, the γ values of humantenidine, gelsenicine, gelsevirine, and humantenine were decreased by 43.69, 41.42, 36.00, and 8.90 percent, respectively. The γ values in presence of ciclosporin were homologous with a decrease of 42.32, 40.59, 34.00, and 15.07 percent. It suggested that the efflux transport was affected by transporters. Taken together, due to the efflux transporters participation, the increasing efflux of indole alkaloids from GM was found in Caco-2 cells.

Pectinate nanofiber mat with high absorbency and antibacterial activity: A potential superior wound dressing to alginate and chitosan nanofiber mats.

Polysaccharides including pectin, alginate and chitosan are fabricated into dressings of micrometer-scaled architecture (micro- fiber or particle) and widely applied in wound treatments clinically. This work characterized and compared the properties of electrospun nanofibrous dressings of these polysaccharides. We found that although the three polysaccharide nanofiber mats had comparable mechanical strength and vapour permeability, the pectinate nanofiber mat could absorb 1.2 times and 3.6 times more exudates than the alginate and chitosan nanofiber mats, respectively, within less time. Moreover, the pectinate nanofiber mat showed much higher antibacterial activity (73.1%) than the alginate and chitosan nanofiber mats (11.8% and 17.1%, respectively). Further examinations demonstrated that the superior absorbency and antibacterial activity of the pectinate nanofiber mat were associated with the moderate extent of swelling of pectinate nanofibers under hydrated conditions. All these results suggest that the pectinate nanofiber mat might be a superior wound dressing to the alginate and chitosan nanofiber mats.

Protective effects of the Tougu Xiaotong capsule on morphology and osteoprotegerin/nuclear factor-κB ligand expression in rabbits with knee osteoarthritis.

The imbalance of subchondral bone remodeling is a common pathological feature in the progression of osteoarthritis. In the current study, using a rabbit model of knee osteoarthritis, the effects of the Tougu Xiaotong capsule (TGXTC) on the cartilage and subchondral bone were investigated. In addition, osteoprotegerin (OPG), an inducer of bone formation, and receptor activator of nuclear factor­κB ligand (RANKL), a regulator of bone resorption in the subchondral bone, were assessed, in order to further explore the protective role of TGXTC in subchondral bone remodeling. The rabbit model of knee osteoarthritis, which was induced by a modified version of Hulth's method, was treated with TGXTC or glucosamine hydrochloride for 4 or 8 weeks. Subsequently, the tibia and femur were harvested for observation of cartilage histology, and the subchondral bone was observed by scanning electron microscopy. The expression levels of OPG and RANKL at the gene and protein levels were determined by reverse transcription­quantitative polymerase chain reaction and western blotting. TGXTC and glucosamine hydrochloride were identified to mitigate cartilage injury, reduce trabecular number and thickness and accelerate trabecular separation. It was additionally observed that the level of OPG mRNA and protein expression was reduced, and the RANKL mRNA and protein expression level was increased, in addition to the observation of a lower OPG/RANKL ratio in the TGXTC and hydrochloride groups. Taken together, these results suggest that TGXTC may mitigate cartilage injury and subchondral sclerosis, thus delaying the pathological development of osteoarthritis. This is suggested to be mediated partly through the reduction of OPG expression and increase of RANKL expression, which reduces the OPG/RANKL ratio, suppressing excessive bone formation.