Intradiscal injection of sesamin protects from lesion-induced degeneration

Intervertebral disc degeneration-related diseases are common health problems in the department of orthopedics. However, there is no effective treatment protecting the intervertebral disc from degeneration. Sesamin, a kind of sesame lignans extracted from sesame seed oil, has been proved to inhibit lipopolysaccharide-induced inflammation and extracellular matrix catabolism in rat intervertebral disc in vitro and ex vivo. The present study was designed to investigate the effects of sesamin on lesion-induced intervertebral disc degeneration in vivo. Degeneration of rat tail disc was induced by puncture lesion, followed by intradiscal injection of sesamin. Magnetic resonance imaging (MRI), quantitative real-time polymerase chain reaction, histological analysis, and biochemical analysis were carried out to analyze degeneration progression 2 weeks after surgery. As shown by results, intradiscal injection of sesamin inhibited the MRI signal decrease of nucleus pulposus (NP) in T2-weighted images. The upregulated mRNA expression of MMP-3 and ADAMTS-5 induced by lesion was significantly suppressed by sesamin injection. Sesamin partly protected mRNA expression of Col2a1 and Acan from downregulation. Intradiscal injection of sesamin effectively maintained the normal morphology of disc and inhibited lesion-induced degeneration-related histological changes. Immunohistochemical assay demonstrated that the upregulation of degradative enzymes protein expression and the downregulation of type II collagen expression in NP were suppressed by sesamin. According to biochemical analysis, sesamin significantly inhibited the lesion-induced decrease of proteoglycan content in NP. The present study proved the protective effects of sesamin on lesion-induced intervertebral disc degeneration at an early stage.