Protective effects of phillyrin on H2O 2-induced oxidative stress and apoptosis in PC12 cells.

Oxidative stress is a major component of harmful cascades activated in neurodegenerative disorders. We sought to elucidate possible effects of phillyrin, an active constituent isolated from the Chinese medicinal herb Forsythia suspense, on hydrogen peroxide (H2O2)-induced cell death and determine the underlying molecular mechanisms in neuron-like PC12 cells. By MTT assay and lactate dehydrogenase (LDH) leakage assay, we found that phillyrin treatment effectively protected PC12 cells against H2O2-induced cell damage. H2O2 exposure induced oxidative stress in PC12 cells, as revealed by enhanced oxidative stress and decreased activities of antioxidative enzymes, which were inhibited by phillyrin pretreatment. ROS activated mitochondria-dependent apoptosis. The anti-apoptotic effects of phillyrin were also confirmed by acridine orange/ethidium bromide (AO/EB) staining. Mitochondrial membrane potential decrease, cytochrome c release, caspases activation, activation of AIF and Endo G were observed in H2O2-treated cells by rhodamine 123 or western blot. Interestingly, phillyrin effectively suppressed these changes. Moreover, phillyrin could inhibit H2O2-induced up-regulation of Bax/Bcl-2 ratio. In conclusion, phillyrin effectively inhibited H2O2-induced oxidative stress and apoptosis in PC12 cells.

Assessment of the Therapeutic Potential of Melatonin for the Treatment of Osteoporosis Through a Narrative Review of Its Signaling and Preclinical and Clinical Studies.

Melatonin is a bioamine produced primarily in the pineal gland, although peripheral sites, including the gut, may also be its minor source. Melatonin regulates various functions, including circadian rhythm, reproduction, temperature regulation, immune system, cardiovascular system, energy metabolism, and bone metabolism. Studies on cultured bone cells, preclinical disease models of bone loss, and clinical trials suggest favorable modulation of bone metabolism by melatonin. This narrative review gives a comprehensive account of the current understanding of melatonin at the cell/molecular to the systems levels. Melatonin predominantly acts through its cognate receptors, of which melatonin receptor 2 (MT2R) is expressed in mesenchymal stem cells (MSCs), osteoblasts (bone-forming), and osteoclasts (bone-resorbing). Melatonin favors the osteoblastic fate of MSCs, stimulates osteoblast survival and differentiation, and inhibits osteoclastogenic differentiation of hematopoietic stem cells. Produced from osteoblastic cells, osteoprotegerin (OPG) and receptor activator of nuclear factor kappa B ligand (RANKL) critically regulate osteoclastogenesis and melatonin by suppressing the osteoclastogenic RANKL, and upregulating the anti-osteoclastogenic OPG exerts a strong anti-resorptive effect. Although the anti-inflammatory role of melatonin favors osteogenic function and antagonizes the osteoclastogenic function with the participation of SIRT signaling, various miRNAs also mediate the effects of the hormone on bone cells. In rodent models of osteoporosis, melatonin has been unequivocally shown to have an anti-osteoporotic effect. Several clinical trials indicate the bone mass conserving effect of melatonin in aging/postmenopausal osteoporosis. This review aims to determine the possibility of melatonin as a novel class of anti-osteoporosis therapy through the critical assessment of the available literature.

Treatment for subtrochanteric fracture and subsequent nonunion in an adult patient with osteopetrosis: A case report and review of the literature.

BACKGROUND: As a congenital metabolic bone disease caused by defective osteoclastic resorption of immature bone, osteopetrosis is characterized by diffused sclerosis of bones, brittle bones, easy fracturing, narrow medullary canals, and a weak fracture healing ability. At present, clear standards and principles for the treatment of fractures in patients with osteopetrosis are lacking. Non-operative treatment can prevent fracture hematoma and preserve the blood supply to the bone fragments, while being associated with frequent failures and higher mortality rates. Meanwhile, closed reduction and internal fixation with intramedullary nail (CRIF + IMN) approaches can also protect blood supply to the fracture site. However, IMN cannot be used for the vast majority of patients with osteopetrosis due to the narrowing of medullary canals. Thus, open reduction and internal fixation with plate remains the most appropriate surgical method for treating fractures in patients with osteopetrosis, but this approach is complicated by the lack of intramedullary hematopoiesis in such patients. Fracture healing primarily depends on the blood supply to the external periosteum. Open reduction can also easily destroy the periosteum and cause delayed fracture healing or even nonunion; however, CRIF may be the most practical approach. As a result, it would be prudent to solve the difficulty of drilling during the operation and the problem of postoperative nonunion. CASE SUMMARY: In 2018, we treated an adult patient with osteopetrosis presenting with a subtrochanteric fracture. The fracture was fixed using a femoral locking compression plate. Because of delayed consolidation, at 12 mo postoperatively the patient was further treated with platelet-rich plasma (PRP) combined with radial extracorporeal shock wave therapy (rESWT). Antero-posterior and lateral radiographs obtained at the latest follow-up (10 mo) showed that the callus had grown at the original fracture site, and the medial fracture line almost disappeared. CONCLUSION: Osteosynthesis remains the first choice of treatment approach for fractures in patients with osteopetrosis, especially peritrochanteric fractures. Preoperative preparation is necessary to avoid risks such as drill bit breakage and iatrogenic fracture during the operation. Moreover, fractures in a patient with osteopetrosis present with a high risk of delayed union and nonunion, which can be potentially cured with PRP + rESWT.

Retardation of fracture healing by cerclage wire near the elbow in radius fracture models.

Cerclage wire is widely used in the treatment of fracture internal fixation and is shown effective in clinic. But a report by S.L. has pointed that the wire loop delayed the growth of bone. We have established a radius fracture model to study the possible detrimental effects of cerclage wire on fracture healing and the potential mechanism. By high-resolution CT analysis cerclage wire is found to delay fracture healing, by histological assessment cerclage wire is found to extended the time of hematoma and the marrow cavity appearing, by confocal microscopy cerclage wire decreased the content of calcium and the expression of alkaline phosphatase (ALP), and by RT-PCR analysis cerclage wire decreased the mRNA levels of bone sialoprotein and ALP. These results suggest that the cerclage wire near the elbow delayed the fracture healing in radius fracture models.

Protective effects of melatonin on lipopolysaccharide-induced mastitis in mice.

Melatonin, a secretory product of the pineal gland, has been reported to have antioxidant and anti-inflammatory effects. However, the protective effects of melatonin on lipopolysaccharide (LPS)-induced mastitis have not been reported. The purpose of this study was to investigate the anti-inflammatory effects and the underlying mechanisms of melatonin on LPS-induced mastitis both in vivo and in vitro. In vivo, our results showed that melatonin attenuated LPS-induced mammary histopathologic changes and myeloperoxidase (MPO) activity. Melatonin also inhibited LPS-induced inflammatory cytokines tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß) and interleukin-6 (IL-6) production in mammary tissues. In vitro, melatonin was found to inhibit LPS-induced TNF-α and IL-6 production in mouse mammary epithelial cells. Melatonin also suppressed LPS-induced Toll-like receptor 4 (TLR4) expression and nuclear factor-kappaB (NF-κB) activation in a dose-dependent manner. In addition, melatonin was found to up-regulate the expression of PPAR-γ. Inhibition of PPAR-γ by GW9662 reduced the anti-inflammatory effects of melatonin. In conclusion, we found that melatonin, for the first time, had protective effects on LPS-induced mastitis in mice. The anti-inflammatory mechanism of melatonin was through activating PPAR-γ which subsequently inhibited LPS-induced inflammatory responses.

Genetically modified Schwann cells producing glial cell line-derived neurotrophic factor inhibit neuronal apoptosis in rat spinal cord injury.

Schwann cells (SCs) are the major cells constituting the peripheral nerve structure and function, and also secret a variety of neurotrophic factors. Schwann cell (SC) transplantation has recently emerged as a promising therapeutic strategy for spinal cord injury (SCI). In the present study, the ability of genetically modified SCs producing high levels of glial cell line­derived neurotrophic factor (GDNF) to promote spinal cord repair was assessed. The GDNF gene was transduced into SCs. The engineered SCs were characterized by their ability to express and secrete biologically active GDNF, which was shown to inhibit apoptosis of primary rat neurons induced by radiation, and upregulate the expression of B­cell lymphoma 2 (Bcl­2) and downregulate the expression of Bcl­2 associated X protein (Bax) in vitro. Following SC implantation into the spinal cord of adult rats with SCI induced by weight­drop impact, the survival of rats with transplanted SCs, histology of the spinal cord and expression levels of Bcl­2 and Bax were examined. Transplantation of unmodified and genetically modified SCs producing GDNF attenuated SCI by inhibiting apoptosis via the Bcl­2/Bax pathways. The genetically modified SCs demonstrated markedly improved recovery of SCI as compared with unmodified SCs. The present study combined the outgrowth­promoting property of SCs with the neuroprotective effects of overexpressed GDNF and identified this as a potential novel therapeutic strategy for SCI.