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.

A carrageenan-degrading marine Cellulophaga lytica strain N5-2 was isolated from the sediment of carrageenan production base. A κ-carrageenase (EC 3.2.1.83) with high activity was purified to electrophoretic homogeneity from the culture supernatant by a procedure of ammonium sulfate precipitation, dialyzing and gel filtration on SephadexG-200 and SephadexG-75. The purified enzyme was verified as a single protein on SDS-PAGE, and whose molecular weight was 40.8 kDa. The κ-carrageenase yielded a high activity of 1170 U/mg protein. For κ-carrageenase activity, the optimum temperature and pH were 35 °C and pH 7.0, respectively. The enzyme was stable at 40 °C for at least 2.5 h. The enzyme against κ-carrageenan gave a K_m value of 1.647 mg/mL and a V_max value of 8.7 μmol/min/mg when the reaction was carried out at 35 °C and pH 7.0. The degradation products of the k-carrageenase were analyzed by thin layer chromatography (TLC), high performance liquid chromatography (HPLC), electrospray ionization time-of-flight mass spectroscopy (ESI-TOF-MS) and ¹³C-NMR spectroscopy, and the results indicated that the enzyme was specific of the β-1,4 linkage and hydrolyzed κ-carrageenan into κ-neocarraoctaose-sulfate and κ-neocarrahexaose-sulfate first, and then broke κ-neocarraoctaose-sulfate into κ-neocarrabiose-sulfate and κ-neocarrahexaose-sulfate.

Blood vessels serve an important role in tumor growth and metastasis, and recent studies have shown that certain tumor cancer stem cells may differentiate into endothelial cells and contribute to angiogenesis. In the present study, vascular endothelial growth factor (VEGF) was used to induce endothelial differentiation of breast cancer stem-like cells (BCSLCs), and methods including flow cytometry, western blotting and immunofluorescence were used to study the relationship between autophagy and the endothelial differentiation of BCSLCs. The results showed that BCSLCs could differentiate into endothelial cells under the induction of VEGF in vitro. Subsequently, the role of autophagy in the endothelial differentiation of BCSLCs was examined. Autophagic activity was measured during endothelial differentiation of BCSLCs, and the association between autophagy and endothelial differentiation was investigated using autophagy activators, autophagy inhibitors and autophagy related 5 (Atg5)-knockdown BCSLCs. Autophagy was increased during endothelial differentiation of BCSLCs, and there was a positive association between autophagy and endothelial differentiation. The ability of cells to undergo endothelial differentiation was reduced in BCSLCs with Atg5 knockdown. Therefore, autophagy was essential for endothelial differentiation of BCSLCs, and the findings of the present study may highlight novel potential avenues for reducing angiogenesis and improving treatment of breast cancer.