Schwann cells (SCs) were cultured on three types of implant surfaces including smooth polished (SMO), sand-blasted, large grit, acid-etched (SLA), and chemically-modified SLA (modSLA). At different time points, the morphology and adhesion of SCs on the implant surfaces were observed by scanning electron microscope. Cell proliferation activity was detected by MTT method. The expression levels of nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) were detected by enzyme-linked immunosorbent assay. Changes in the mRNA levels of NGF and BDNF were detected by real-time fluorescent quantitative polymerase chain reaction (PCR).

SCs adhered, stretched, and proliferated well on the three types of implant surfaces. On the 3rd, 5th, and 7th days, the OD values of the SMO group were higher than those of the SLA group and the modSLA group, and the difference was statistically significant (P<0.05). On the 3rd day, the expression and mRNA levels of NGF and BDNF in the SLA group and the modSLA group were higher than those in the SMO group (P<0.05); in particular, the levels in the modSLA group were higher than those in the SLA group (P<0.05).

Different implant surface properties have different effects on the biological behavior of SCs. Proliferation of SCs is significantly promoted by smooth surface, while secretion and gene expression of neurotrophic factors are significantly promoted by modSLA surface at early stage.