The structurally diverse phytocannabinoids cannabichromene, cannabigerol and cannabinol significantly inhibit amyloid ß-evoked neurotoxicity and changes in cell morphology in PC12 cells.

BACKGROUND: Phytocannabinoids (pCBs) have been shown to inhibit the aggregation and neurotoxicity of the neurotoxic Alzheimer's disease protein beta amyloid (Aß). We characterized the capacity of six pCBs-cannabichromene (CBC), cannabigerol (CBG), cannabinol (CBN), cannabidivarin (CBDV), cannabidiol (CBD) and Δ9 -tetrahydrocannabinol (Δ9 -THC)-to disrupt Aß aggregation and protect against Aß-evoked neurotoxicity in PC12 cells. METHODS: Neuroprotection against lipid peroxidation and Aß-induced cytotoxicity was assessed using the MTT assay. Transmission electron microscopy was used to visualize pCB effects on Aß aggregation and fluorescence microscopy, with morphometrics and principal component analysis to assess PC12 cell morphology. RESULTS: CBD inhibited lipid peroxidation with no significant effect on Aß toxicity, whilst CBN, CBDV and CBG provided neuroprotection. CBC, CBG and CBN inhibited Aß1-42 -induced neurotoxicity in PC12 cells, as did Δ9 -THC, CBD and CBDV. CBC, CBN and CBDV inhibited Aß aggregation, whilst Δ9 -THC reduced aggregate density. Aß1-42 induced morphological changes in PC12 cells, including a reduction in neuritic projections and rounded cell morphology. CBC and CBG inhibited this effect, whilst Δ9 -THC, CBD and CBDV did not alter Aß1-42 effects on cell morphology. CONCLUSIONS: These findings highlight the neuroprotective activity of CBC, CBG and CBN as novel pCBs associated with variable effects on Aß-evoked neurite damage and inhibition of amyloid ß aggregation.

Performance of a Biodegradable Composite with Hydroxyapatite as a Scaffold in Pulp Tissue Repair.

Vital pulp therapy is an important endodontic treatment. Strategies using growth factors and biological molecules are effective in developing pulp capping materials based on wound healing by the dentin-pulp complex. Our group developed biodegradable viscoelastic polymer materials for tissue-engineered medical devices. The polymer contents help overcome the poor fracture toughness of hydroxyapatite (HAp)-facilitated osteogenic differentiation of pulp cells. However, the composition of this novel polymer remained unclear. This study evaluated a novel polymer composite, P(CL-co-DLLA) and HAp, as a direct pulp capping carrier for biological molecules. The biocompatibility of the novel polymer composite was evaluated by determining the cytotoxicity and proliferation of human dental stem cells in vitro. The novel polymer composite with BMP-2, which reportedly induced tertiary dentin, was tested as a direct pulp capping material in a rat model. Cytotoxicity and proliferation assays revealed that the biocompatibility of the novel polymer composite was similar to that of the control. The novel polymer composite with BMP-2-induced tertiary dentin, similar to hydraulic calcium-silicate cement, in the direct pulp capping model. The BMP-2 composite upregulated wound healing-related gene expression compared to the novel polymer composite alone. Therefore, we suggest that novel polymer composites could be effective carriers for pulp capping.