Naringenin reduces oxidative stress and necroptosis, apoptosis, and pyroptosis in random-pattern skin flaps by enhancing autophagy.

BACKGROUND: Random skin flap grafting is one of the most commonly used techniques in plastic and orthopedic surgery. However, necrosis resulting from ischemia and ischemia-reperfusion injury in the distal part of the flap can severely limit the clinical application of the flap. Studies have revealed that naringenin reduces pyroptosis, apoptosis, and necroptosis, inhibits oxidative stress, and promotes autophagy. In this study, the effects of Naringenin on flap viability and its underlying mechanism were evaluated. METHODS: Mice with random skin flaps were randomly allocated to control, Naringenin, and Naringenin + 3-methyladenine groups. On postoperative day 7, flap tissues were collected to estimate angiogenesis, necroptosis, apoptosis, pyroptosis, oxidative stress, and autophagy via hematoxylin and eosin staining, immunofluorescence, and immunohistochemistry. RESULTS: The results revealed that naringenin promoted the viability of the random flaps as well as angiogenesis, while inhibiting oxidative stress and decreasing pyroptosis, apoptosis, and necroptosis. These effects were reversed by the autophagy inhibitor 3-methyladenine. CONCLUSIONS: The findings indicated that naringenin treatment could promote flap survival by inhibiting pyroptosis, apoptosis, necroptosis, and alleviating oxidative stress, caused by the activation of autophagy.

Three-dimensional bioprinted BMSCs-laden highly adhesive artificial periosteum containing gelatin-dopamine and graphene oxide nanosheets promoting bone defect repair.

The periosteum is a connective tissue membrane adhering to the surface of bone tissue that primarily provides nutrients and regulates osteogenesis during bone development and injury healing. However, building an artificial periosteum with good adhesion properties and satisfactory osteogenesis for bone defect repair remains a challenge, especially using three-dimensional (3D) bioprinting. In this study, dopamine was first grafted onto the molecular chain of gelatin usingN-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride andN-hydroxysuccinimide (NHS) to activate the carboxyl group and produce modified gelatin-dopamine (GelDA). Next, a methacrylated gelatin, methacrylated silk fibroin, GelDA, and graphene oxide nanosheet composite bioink loaded with bone marrow mesenchymal stem cells was prepared and used for bioprinting. The physicochemical properties, biocompatibility, and osteogenic roles of the bioink and 3D bioprinted artificial periosteum were then systematically evaluated. The results showed that the developed bioink showed good thermosensitivity and printability and could be used to build 3D bioprinted artificial periosteum with satisfactory cell viability and high adhesion. Finally, the 3D bioprinted artificial periosteum could effectively enhance osteogenesis bothin vitroandin vivo. Thus, the developed 3D bioprinted artificial periosteum can prompt new bone formation and provides a promising strategy for bone defect repair.

Estrogen Regulation of the Expression of Pain Factor NGF in Rat Chondrocytes.

OBJECTIVE: Pain is the main symptom of osteoarthritis (OA). Nerve growth factor (NGF) plays a crucial role in the generation of OA pain. And estrogen-alone used resulted in a sustained joint pain reduction in postmenopausal women. So we aim to find whether estrogen alters chondrocytes' NGF level, affecting OA pain. METHODS: Primary chondrocytes and cartilage explants isolated from Sprague Dawley rat knees were cultured with physiological concentrations of estrogen (17ß-Estradiol ≥ 98%, E2), Estrogen Receptor α (ERα) inhibitor and stimulants. Then, chondrocytes NGF mRNA expression and protein release were analyzed by a quantitative real-time polymerase chain reaction (qPCR) and enzyme-linked immunosorbent assay (ELISA) respectively. Additionally, cultures were pre-incubated with MEK-ERK inhibitor to identify the signaling pathway that estrogen alters NGF mRNA and protein levels. RESULTS: We found that chondrocytes NGF expression and release were decreased by E2. E2 also reduced chondrocytes IL-1ß-stimulated or TGF-ß1-stimulated NGF expression. Phosphorylated extracellular signal-regulated kinasep1/2 (p-ERK1/2) signals were detected stronger than the control group by Western Blotting (WB). When we cultured chondrocytes with PD98059 (MEK-ERK inhibitor, PD), NGF mRNA expression was added to 1.41Ct (2.07±0.1 fold). CONCLUSION: We showed that E2 reduces chondrocytes NGF expression significantly, even after stimulation by TGF-ß1 or IL-1ß. MEK-ERK signaling is involved in this process.

Mechanism and therapeutic effectiveness of nerve growth factor in osteoarthritis pain.

Osteoarthritis (OA) is the most common form of articular joint arthritis and a cause of significant morbidity. In this review, we present the role of nerve growth factor (NGF) in pain generation, relationship between NGF and OA pain, and pathogenic factors (interleukin-1ß, transforming growth factor-ß1, mechanical loading, and adipokines) involved in OA development. Since NGF blocking is an efficient way to inhibit OA-associated pain, we summarize four categories of drugs that target NGF/tropomyosin receptor kinase A (TrkA) signaling. In addition, we discuss the future of NGF/TrkA antagonists and underline their potential for use in OA pain relief. A better understanding of the causes and treatment of OA will facilitate the development of more effective methods of OA pain management.

Regulation of type II collagen, matrix metalloproteinase-13 and cell proliferation by interleukin-1ß is mediated by curcumin via inhibition of NF-κB signaling in rat chondrocytes.

Curcumin possesses strong anti-inflammatory, anti-rheumatoid and anti-oxidative activities, and has the potential to inhibit nuclear factor­κB (NF­κB) signaling. Cartilage damage in osteoarthritis (OA) is largely mediated by interleukin-1ß (IL-1ß) via activation of various transcription factors, including NF­κB and activator protein­1. The aim of the present study was to determine whether IL­1ß induces matrix metalloproteinase-13 (MMP-13) expression and inhibits type II collagen expression, as well as to examine whether cell proliferation may be inhibited by curcumin through the inhibition of NF­κB signaling. The effects of curcumin were investigated in rat articular chondrocyte cell cultures treated with IL­1ß in the presence or absence of curcumin or the NF­κB inhibitor pyrrolidine dithiocarbamate. Western blotting and reverse transcription­quantitative polymerase chain reaction were conducted to evaluate protein and mRNA expression levels of type II collagen, MMP­13, NF­κB inhibitor α (IκBα), phosphorylated­IκBα and NF­κB subunit p65/RelA. Western blotting and immunofluorescence were performed to examine the effects of curcumin on the expression, phosphorylation and nuclear translocation of NF­κB­associated proteins. The effects of curcumin on cell proliferation were evaluated by Cell Counting Kit­8 (CCK­8). Curcumin was demonstrated to inhibit the IL­1ß­induced activation of NF­κB by suppressing IκBα phosphorylation and p65/RelA nuclear translocation. These events were associated with the downregulation of MMP­13 expression and the upregulation of type II collagen expression, both of which are considered to be NF­κB targets. CCK­8 assays revealed that co­treatment with curcumin resulted in increased proliferation in IL­1ß­treated chondrocytes. These findings implicated curcumin as a naturally occurring anti­inflammatory agent for the treatment of OA via inhibition of NF­κB signaling.

Recurrent Neurological Deterioration after Conservative Treatment for Acute Traumatic Central Cord Syndrome without Bony Injury: Seventeen Operative Case Reports.

The mechanisms of late recurrent neurological deterioration after conservative treatment for acute traumatic central cord syndrome (ATCCS) remain unclear. Seventeen operative cases sustaining late recurrent neurological deterioration after conservative treatment for ATCCS were reviewed to investigate the mechanisms. The assessment of neurological status was based on International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI). Gender, age, cause of injury, results of image, conservative treatment and operative data, and neurological status at different time points were recorded. The mean age of 17 patients was 43.8 ± 2.3 years old, and the causes of the cervical injury were 14 vehicle accidents and 3 falls. The neurological deficits of 17 patients on admission were not serious, and patients recovered quickly after conservative treatment. No fractures or dislocation were found in any patient's radiographs or CT scan images. All 17 patients performed first MRI test in 4 days and there was a slight or mild compression on the spinal cord in 16 patients. Eight patients had a second MRI scan ∼6 weeks later, which showed that there was aggravated compression on the spinal cord in six patients. All patients underwent an anterior approach to cervical decompression and internal fixation operation. During the operation, there were loose discs found in all 17 patients, obvious ruptures of disks found in 3 patients, obvious ruptures of anterior longitudinal ligaments (ALLs) found in 8 patients, and obvious ruptures of posterior longitudinal ligaments (PLLs) found in 7 patients. There was serious adhesion between PLLs and cervical disks in 12 patients. In five patients, partial ossification of PLLs was detected. All patients had a good neurological outcome at 6 month follow-up. Ruptures of ALLs, PLLs, and discs resulting in cervical instability and secondary compression on the spinal cord were important causes for recurrent neurological deterioration after conservative treatment for ATCCS. With timely spinal decompression after recurrent neurological deterioration, patients could achieve a good neurological outcome.