Abstract
Background Synaptic failure is one of the principal events associated with cognitive dysfunction in Alzheimer’s disease (AD). Preservation of existing synapses and prevention of synaptic loss are promising strategies to preserve cognitive function in AD patients. As a potent natural anti-oxidant, anti-amyloid, anti-inflammatory polyphenol, curcumin (Cur) shows great promise as a therapy for AD. However, hydrophobicity of natural Cur limits its solubility, stability, bioavailability and clinical utility for AD therapy. We have demonstrated that solid lipid curcumin particles (SLCP) have greater therapeutic potential than natural Cur in vitro and in vivo models of AD. In the present study, we have investigated whether SLCP has any preservative role on affected dendritic spines and synaptic markers in 5xFAD mice.Methods Six- and 12-month-old 5xFAD and age-matched wild-type mice received oral administration of SLCP (100 mg/kg body weight) or equivalent amounts of vehicle for 2 months. Neuronal morphology, neurodegeneration and amyloid plaque load were investigated from prefrontal cortex (PFC), entorhinal cortex (EC), CA1, CA3 and the subicular complex (SC). Further, dendritic spine density of apical and basal branches were studied by Golgi-Cox stain. Further, synaptic markers, such as synaptophysin, PSD95, Shank, Homer, Drebrin, kalirin-7, CREB and phosphorylated CREB (pCREB) were studied using Western blots. Finally, cognitive and motor functions were assessed using open field, novel object recognition (NOR) and Morris water maze (MWM) tasks after treatment with SLCP.Results We observed an increase number of pyknotic and degenerated cells in all these brain areas in 5xFAD mice and SLCP treatment partially protected against those losses. Decrease in dendritic arborization and dendritic spine density from primary and secondary apical and basal branches were observed in PFC, EC, CA1, CA3 in both 6- and 12-month-old 5xFAD mice and SLCP treatments partially preserved the normal morphology of these dendritic spines. In addition, pre- and post-synaptic protein markers were also restored by SLCP treatment. Furthermore, SLCP treatment improved NOR and cognitive function in 5xFAD mice.Conclusions Overall, these findings indicate that use of SLCP exerts neuroprotective properties by decreasing amyloid plaque burden, preventing neuronal death, as well as preservation of dendritic spine density and synaptic markers in the 5xFAD mice.
Prenatal cocaine exposure increases anxiety, impairs cognitive function and increases dendritic spine density in adult rats: influence of sex
