Objective: To investigate the protective mechanism of berberine on HT22 cells induced by β-amyloid protein 25-35 (Aβ25-35) and observe its effect of toll-like receptor 4 (TLR4)/nuclear factor-κB(NF-κB) signaling pathway. Method: HT22 cells were cultured and different concentrations of berberine (0

5

10

20

40

80 μmol·L-1) were incubated. After 24 h

methylthiazolyl tetrazolium (MTT) assay was used to determine the protective concentration of berberine. Then HT22 cells were divided into blank group

Aβ group

berberine group and TAK 242 group. HT22 cells in blank group were treated with serum-containing media alone; HT22 cells in Aβg roup were treated with Aβ25-35 (40 μmol·L-1); while HT22 cells in berberine group and TAK 242 group were treated with berberine (20 μmol·L-1) and TAK 242 (20 μmol·L-1)r espectively for 1 h

followed by Aβ25-35 (40 μmol·L-1) treatment. After 24 h

lactate dehydrogenase (LDH) release test was used to measure the cell survival rate. Hoechst 33342 staining was used to determine the apoptosis rate. Western blot was used to detect the protein expression levels of TLR4

phosphorylated (p)-NF-κB

tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β). Result: As compared with the blank group

20 μmol·L-1 berberine promoted cell proliferation; 40 and 80 μmol·L-1 berberine inhibited cell proliferation (P<0.01); among them

20 μmol·L-1 berberine group had the highest cell proliferation rate (P<0.01). As compared with the blank group

the cell survival rate was decreased in Aβ group (P<0.01) and the cell survival rates in berberine group and TAK 242 group were higher than that of the Aβ group (P<0.01). As compared with the blank group

the apoptosis rate was increased in Aβ group (P<0.01)

and chromatin condensation

nuclear atrophy

and increased apoptotic bodies were observed. As compared with the Aβ group

the apoptotic rate was lower in berberine group and TAK 242 group (P<0.01)

with less chromatin condensation

nuclear atrophy and apoptotic bodies. As compared with the blank group

the expression levels of TLR4

p-NF-κB

TNF-α and IL-1β were increased in the Aβ group (P<0.01). As compared with the Aβ group

the expression levels of TLR4

p-NF-κB

TNF-α and IL-1β were lower in berberine group and TAK 242 group (P<0.01). Conclusion: Berberine may protect against neuronal apoptosis by inhibiting the Aβ25-35-activated TLR4/NF-κB pathway in HT22 cells.