title: Therapeutic effects of naringin on degenerative human nucleus pulposus cells for discogenic low back pain.
abstract: Over half the population of the world will suffer from moderate or severe low back pain (LBP) during their life span. Studies have shown that naringin, a major flavonoid in grapefruit and an active compound extracted from a Chinese herbal medicine (Rhizoma Drynariae) possesses many pharmacological effects.
  
  
  
  The aim of this study was to evaluate the influence of naringin on the growth of degenerative human nucleus pulposus (NP) cells, and its repair effects on protein and gene expressions of the cells.
  
  
  
  This was an in vitro investigation of the human NP cells isolated from degenerated intervertebral discs that were interacted with various concentrated of naringin.
  
  
  
  This study was exempted by the institutional Human Subjects Committee-2, University of Kansas School of Medicine-Wichita. Degenerative human NP cells were isolated from intervertebral discs of patients with discogenic LBP and cultured at 37°C with 5% CO2. The proliferation of NP cells was determined following treatment with various concentrations of naringin. The protein expressions of tumor necrosis factor-α (TNF-α) and Bone morphogenetic protein 2 (BMP-2) were tested using enzyme-linked immunosorbent assay. Aggrecan and type II collagen levels were measured by immunohistological staining. Further examination of the gene expression of aggrecan, Sox6, and MMP3 was performed after intervention with naringin for 3 days.
  
  
  
  The human NP cells were successfully propagated in culture and stained positive with toluidine blue staining. Naringin effectively enhanced the cell proliferation at an optimal concentration of 20 µg/mL. Naringin treatment resulted in significant inhibition of TNF-α, but elevated protein expressions of BMP-2, collagen II, and aggrecan. Naringin also increased disc matrix gene activity including aggrecan and Sox6, and decreased the gene expression of MMP3.
  
  
  
  Naringin effectively promotes the proliferation of degenerative human NP cells and improves the recuperation of the cells from degeneration by increasing expression of aggrecan, BMP-2, and Sox6 while inhibiting the expression of TNF-α and MMP3. This study suggests that naringin may represent an alternative therapeutic agent for disc degeneration.
authors.affiliation: Department of Orthopedics, University of Kansas School of Medicine-Wichita, 929 N Saint Francis St, Wichita, KS, USA; Department of Orthopaedic Surgery, Affiliated Hospital to Shandong University of Traditional Chinese Medicine, 42 Wenhua West Road, Jinan, China.
authors.forename: Nianhu
authors.initials: N
authors.lastname: Li
authors.affiliation: Department of Orthopedics, University of Kansas School of Medicine-Wichita, 929 N Saint Francis St, Wichita, KS, USA.
authors.forename: Camden
authors.initials: C
authors.lastname: Whitaker
authors.affiliation: Department of Orthopaedic Surgery, Affiliated Hospital to Shandong University of Traditional Chinese Medicine, 42 Wenhua West Road, Jinan, China.
authors.forename: Zhanwang
authors.initials: Z
authors.lastname: Xu
authors.affiliation: Department of Orthopedics, University of Kansas School of Medicine-Wichita, 929 N Saint Francis St, Wichita, KS, USA; Robert J. Dole Veterans Administration Hospital Center, 5500 E. Kellogg, Wichita, KS, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Heggeness
authors.affiliation: Department of Orthopedics, University of Kansas School of Medicine-Wichita, 929 N Saint Francis St, Wichita, KS, USA; Department of Biological Sciences, Wichita State University, 1845 Fairmount Street, Wichita, KS, USA. Electronic address: syang6@kumc.edu.
authors.forename: Shang-You
authors.initials: SY
authors.lastname: Yang
mesh_terms: D053674:Aggrecans / Q000378:metabolism; D055396:Bone Morphogenetic Protein 2 / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects*; D002478:Cells, Cultured; D024043:Collagen Type II / Q000378:metabolism; D044950:Flavanones / Q000494:pharmacology* / Q000627:therapeutic use; D006801:Humans; D055959:Intervertebral Disc Degeneration / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology*; D017116:Low Back Pain / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology*; D000070614:Nucleus Pulposus / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D053674:Aggrecans; C525718:BMP2 protein, human; D055396:Bone Morphogenetic Protein 2; D024043:Collagen Type II; D044950:Flavanones; D014409:Tumor Necrosis Factor-alpha; C005274:naringin
keywords: Aggrecan; Disc degeneration; Intervertebral disc matrix; Naringin; Nucleus pulposus cells; TNF-α