κ-Carrageenan Oligosaccharides Inhibit the Inflammation of Lipopolysaccharide-Activated Microglia Via TLR4/NF-κB and p38/JNK MAPKs Pathways.

Microglial inflammation plays an essential role in neurodegenerative disease. Our previous studies had shown that κ-carrageenan oligosaccharides (KOS) could inhibit the excessive activation of microglia that induced by LPS, while the interrelated mechanisms were still indistinct. Therefore, we detected the inflammatory signaling pathway on LPS-activated microglia that pretreat by different content of KOS to reveal the mechanism on KOS's inhibition of microglia inflammatory response. ELISA was used to detect the effects of KOS on the secretion of interleukin-1 (IL-1ß), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and prostaglandin E2 (PG-2) by LPS-activated microglia, respectively. The production of reactive oxygen species (ROS) and nitric oxide (NO) in microglia cells was detected by flow cytometry, and the protein expression of immunoinflammation-related signaling pathways were detected by Western Blot. The results showed that KOS could significantly protected the microglia from the over-activated inflammatory by inhibiting the release of inflammatory cytokines and the oxidative stress response. And KOS could reduce the expression of the protein that related to the TLR4/NF-κB and p38/JNK MAPKs pathways activated by LPS in microglia. However, there may be no specific target of KOS in cells. Therefore, KOS, a natural algal source oligosaccharide, has immunomodulatory effects and can be used as a potential intervention therapy for inflammatory related neurodegenerative diseases.

Immunomodulatory function of κ-carrageenan oligosaccharides acting on LPS-activated microglial cells.

The major neurodegenerative diseases are characterized by increasing of activated-microglial cells and inflammatory cytokines in the central nervous system. Carrageenan extracted from red algae is a kind of polysaccharide with sulfate groups. The oligosaccharides were obtained from carrageenan by enzymatic degradation. To detect the immunomodulatory activity of κ-carrageenan oligosaccharides (KOS) on microglial cells and the relationship to the sulfate group content, the desulfated derivatives of KOS (DSK) were obtained by dimethyl sulfoxide-methanol-pyridine method. KOS was labeled with fluorescein isothiocyanate. The effect of KOS and DSK on lipopolysaccharide (LPS)-activated microglial cells was detected. Hematoxylin-eosin staining and flow cytometric were used to detect the cell viability. The "scratch" migration assay, ornithine analysis and RT-PCR were used to determine the cell migration, arginase and TNF-α released by microglial cells, respectively. The effect of LPS and KOS on microglial cells was determined by flow cytometry and laser scanning confocal microscopy. The results showed that KOS and DSK could inhibit the cell viability, arginase and TNF-α released by LPS-activated microglia cell with concentration dependent manner. But the effect of DSK was weaker than that of KOS. KOS aggregated on the cell surface firstly, and then they enter into the cell to the nucleus, spread over the entire cell finally. But the exist of LPS could prevent the entrance of KOS. It could be concluded that KOS could protect microglial cells from being activated by LPS, and its inhibition function had relationship to the sulfate group content of KOS, while there were competition between LPS and KOS.

κ-Carrageenan oligosaccharides induce microglia autophagy through AMPK/ULK1 pathway to regulate their immune response.

Microglia are the main effector cells of immune response in central nervous system and are important targets for disease prevention and treatment. Κ-carrageenan Oligosaccharide (KOS), obtained by enzymatic hydrolysis from carrageenan of marine red algae, can inhibit the release of inflammatory factors from the over-activated microglia. The mechanism of microglia autophagy induced by KOS and its relationship with inflammation were studied to explore the development prospect of KOS in the research and treatment of inflammatory related diseases. The effect of KOS on inducing autophagy was detected by the secretion of cytokines by lipopolysaccharide (LPS)-activated microglia, respectively. The protein expression of autophagy-related signaling pathways were detected by Western Blot. The results showed that KOS could significantly protect the microglia from over-activated inflammatory by inducing the autophagy and inhibiting the release of inflammatory cytokines. And KOS could reduce the expression of the protein that related to the AMPK/ULK1 pathways in microglia, so as to regulate the autophagy pathway, and inhibit the inflammatory response of over-activated microglia. The study on the effect of KOS on microglia autophagy and excessive inflammatory response will provide a theoretical basis for further studies on the inhibition of nerve injury by regulating microglia autophagy and inflammatory response.

Efficacy of chitosan and sodium alginate scaffolds for repair of spinal cord injury in rats.

Spinal cord injury results in the loss of motor and sensory pathways and spontaneous regeneration of adult mammalian spinal cord neurons is limited. Chitosan and sodium alginate have good biocompatibility, biodegradability, and are suitable to assist the recovery of damaged tissues, such as skin, bone and nerve. Chitosan scaffolds, sodium alginate scaffolds and chitosan-sodium alginate scaffolds were separately transplanted into rats with spinal cord hemisection. Basso-Beattie-Bresnahan locomotor rating scale scores and electrophysiological results showed that chitosan scaffolds promoted recovery of locomotor capacity and nerve transduction of the experimental rats. Sixty days after surgery, chitosan scaffolds retained the original shape of the spinal cord. Compared with sodium alginate scaffolds- and chitosan-sodium alginate scaffolds-transplanted rats, more neurofilament-H-immunoreactive cells (regenerating nerve fibers) and less glial fibrillary acidic protein-immunoreactive cells (astrocytic scar tissue) were observed at the injury site of experimental rats in chitosan scaffold-transplanted rats. Due to the fast degradation rate of sodium alginate, sodium alginate scaffolds and composite material scaffolds did not have a supporting and bridging effect on the damaged tissue. Above all, compared with sodium alginate and composite material scaffolds, chitosan had better biocompatibility, could promote the regeneration of nerve fibers and prevent the formation of scar tissue, and as such, is more suitable to help the repair of spinal cord injury.

The antithrombotic action of propylene glycol mannite sulfate (PGMS).

In order to reveal the antithrombotic mechanism of propylene glycol mannite sulfate (PGMS) on gene level and explore the correlation between PGMS and fibrinolytic system, the urokinase-type plasminogen activator (uPA) mRNA expression and uPA activity were detected in vitro and in vivo with semi-quantitative reverse transcription (RT)-PCR and chromogenic method. The results showed that PGMS was able to increase uPA activity in dosage-dependent manner in rat plasma, which resulted in the increase of rat fibrinolytic activity. The change of rat uPA mRNA expression with PGMS was similar to that of uPA activity. The results of experiments with cultured cells were similar to those results of experiments in vivo. The uPA mRNA expression and activities of cultured cells showed increases with PGMS in a concentration-dependent manner. All of these results indicated that PGMS may induce the expression of uPA mRNA. The increase of uPA mRNA expression may therefore reflect, in part, an increase in the stability of uPA mRNA and/or processing of nuclear uPA transcription, which, in turn, may increase the uPA activity in rat plasma and trigger the fibrinolytic system.