The regulatory effects of niacinamide （Nia） on intervertebral disc （IVD） aggrecan in vitro was investigated. Chiba＇s 10 ng/mL interleukin-1 （IL-1）-induced rabbit IVD degeneration model in vitro was established. 0.5, 0. 25 and 0.05 mg/mL Nia was added to normal and degenerated IVDs for intervention. On the first and second week after intervention, safranin O-fast green staining intensity and glycosaminoglycan （GS） content were measured. The expression of aggrecan core protein was detected by RT-PCR. The results showed： （1） After treatment with 0. 5 mg/mL Nia for one week, the GS content in nucleus pulposus （NP） was increased by 44.80% as compared with control group （P〈0. 01） ; The GS content in IL-1 induction groups was increased with the increase of Nia concentrations： After treatment with 0. 5 mg/mL for one week, the GS content in NP was increased by 68.30% as compared with control group （P〈0. 01）. After two weeks, GS content in NP and fibrous rings was still higher than in control group at the same period （P〈0. 01） and untreated group （P〈0.01）. （2） Safranin O-fast green staining revealed that with the increase of Nia concentrations, staining density in NP and fibrous rings was increased and histological structure damage to IVDs by IL-1β was alleviated. （3） RT-PCR showed that the expression of core protein gene in IL-1β-induced degenerated IVDS was increased with the increase of Nia concentrations. It was concluded that under conditions in vitro, Nia could up-regulate the expression of aggrecan in IVDs and protect IVDs from IL-1β-induced degeneration at least partially, which offers a potential choice for IVD degeneration clinical therapy.
