OBJECTIVETo investigate the effects of insulin-like growth factor-1 (IGF-1) on cell injuries and tau hyperphosphorylation induced by okadaic acid (OA).

METHODSThe experimental groups were designed as follows: (1) SH-SY5Y culture (control group); (2) SH-SY5Y exposed to 40 nmol/L OA for 24 hours (OA group); (3) SH-SY5Y exposed to OA for 24 hours in the presence of 2 hour pretreatment with 100, 200 and 400 ng/ml IGF-1 (IGF-1 pretreatment groups). The changes of cell morphology were observed by inverted microscope. The viability of cells was detected by MTT. The injuries of cells were examined by Hoechst 33258 staining and the activity of caspase-3. Western-blot was applied to determine the expression of phosphorylation of tau protein.

RESULTSIn IGF-1 pretreatment group, the cell morphology was improved, the viability of cells was increased, and caspase-3 activation and hyperphosphorylation of tau (Ser396) were reduced.

CONCLUSIONIGF-1 can protect the SH-SY5Y cells from cell injuries induced by OA by inhibiting tau hyperphosphorylation.