Objective: To observe the effect of curcumin on autophagic flux in Neuro-2a mouse brain neuroma cells of expressing APP695swe stably (N2a/APP695swe) and explore the potential mechanism. Methods: Firstly

cells were divided into 4 groups: wild type group (WT)

blank control group (Control)

solvent control group (Sham) and curcumin group (Curcumin). Transmission electron microscopy (TEM) was performed to observe the morphological characteristics of autophagosomes in each group

Western blot was used to test the expressions of p62 and LC3Ⅱproteins. Meanwhile

Western blot and immunofluorescence staining were performed to detect the expression of Rab7 protein

and quantitative real-time PCR (qRT-PCR) was carried out to analyze the mRNA level of Rab7. Then cells were divided into 5 groups after transfection of pcDNA3.1

pcDNA3.1-Rab7

NC-siRNA and Rab7-siRNA respectively: Control group

pcDNA3.1 group

pcDNA3.1-Rab7 group

NC-siRNA group and Rab7-siRNA group. The morphological characteristics of autophagosomes were observed by transmission electron microscopy

and the levels of p62 and LC3Ⅱproteins were detected by Western blot

too. Results: After treatment of curcumin

autolysosomes with monolayer were observed by TEM. And the expression of LC3Ⅱprotein was increased (P=0.000)

while the expression of p62 was decreased (P=0.000). Meanwhile

the expressions of Rab7 were increased at both protein and mRNA levels (P=0.000

0.000). After over-expression of Rab7

more autolysosomes were observed

and the expression of p62 protein was reduced (P=0.000)

while the expression of LC3Ⅱprotein did not change significantly (P=0.669). After transfection of Rab7-siRNA in N2a/APP695swe cells

autophagosomes with double membranes were observed visibly. The expression of p62 protein was elevated (P=0.000)

while the expression of LC3Ⅱprotein did not change prominently (P=0.622). Conclusion: Curcumin stimulates autophagy flux in N2a/APP695swe cells

and the mechanism may be related to the enhancement of Rab7.