Polymorphisms of pro-inflammatory cytokine genes could take part in IVDD pathophysiology as the result of alteration in their expression levels or structures. The current study indicated significant roles of TNF-α -308 G/A and TNF-α -238 G/A SNPs with IVDD among Iranian patients. However, this study did not show any significant association between IVDD and either of SNPs of IL-1 and IL-6 genes.

BackgroundConsidered as one of the major causes of low back pain, Intervertebral disc degeneration (IVDD) is caused by several genetic and environmental factors. As inflammation plays an important role in disc degeneration, the genetic changes in both inflammatory and anti-inflammatory genes may play causative roles in IVDD as well. Therefore, the interactions between inflammatory and anti-inflammatory cytokines and also other components of disc matrix would determine the degree of tissue destruction in disc degeneration. However, there is still controversy regarding the exact role of inflammation and disc homeostasis imbalance in pathophysiology of IVDD. Therefore, current study was conducted to investigate the role of IL-10 and TGF-β single nucleotide polymorphisms (SNP) in Iranian IVDD patients.MethodsSeventy-six IVDD patients and 140 healthy controls were enrolled in this study. Genomic DNA from peripheral leukocytes was tested for 3 SNPs in IL10 (L-10 -1082G/A (rs1800896), IL-10 -819C/T (rs1800871), IL-10 -592A/C (rs1800872)) and 2 SNPs in TGF-β (TGF-β Codon 10 C/T (rs1982037), and TGF-β Codon 25 C/T (rs1800471) genes through PCR-SSP method. The extracted genomic DNA was genotyped for the aforementioned SNPs of interest using specific primers, which were coated in the cytokines KITs and based on the PCR-SSP method for sequencing.ResultsThe ‘T’ allele of IL-10 -819C/T and the ‘C’ allele of IL-10 -592A/C were more prevalent among patients, whereas the ‘C’ and ‘A’ alleles of respective SNPs were significantly more frequent in controls. The genotypes including ‘CT’ of IL-10 -819C/T, ‘CA’ of IL-10 -592A/C, and ‘GA’ of IL-10 -1082A/G were more common among patients, while the ‘CC’ genotype of both IL-10 -819C/T and IL-10 -592A/C SNPs were more frequent in controls. In addition, the IL-10 haplotypes including ‘ACC’, ‘ATA’, and ‘ACA’ were significantly associated with disease. Meanwhile, the ‘TC’ haplotype of TGF-β was more common among patients as well.ConclusionsThe IL-10 SNPs were significantly associated with IVDD in Iranian population; which proposes that genomic alterations of anti-inflammatory cytokines could lead to homeostasis imbalance in intervertebral discs and degenerative changes.

Background: Intervertebral disc degeneration (IVDD) is a multifactorial disease that is sensitive to the balance between anti-inflammatory and pro-inflammatory cytokines. This study investigated the single nucleotide polymorphisms (SNPs) of interleukin 4 (IL-4) in IVDD. Methods: Genomic DNA of peripheral mononuclear cells of 76 IVDD patients and 140 healthy controls were investigated for three SNPs of IL-4 (rs2243248 (−1098G/T), rs2243250 (−590 C/T), rs2070874 (−33 C/T)) and 1 SNP of IL-4RA (rs180275, +1902 A/G) through PCR-SSP method. Results: The 'C' allele frequency of IL-4 rs2243250 was 104 in 76 patients, while it was 149 in 140 controls (OR = 2, p =.001); also this SNP was significantly associated with post-operative pain reduction. The 'C' allele of IL-4 rs2070874 (130 in 76 patients, and 200 in 140 controls, OR = 2.66), and the 'CC' genotype were more frequent among patients (OR = 3.98, p <.001) than controls. 'TTT' haplotype was more common in controls (OR = 0.36, p <.001) and 'TCC' was also more common in patients (OR = 1.75, p =.012). A meta-analysis of previous studies found significantly higher IL-4 levels in disc tissues of IVDD patients, which was not similarly found in blood samples. Conclusion: The immune system plays an important role in IVDD. The extent and progress of the disease vary significantly with IL-4 level. Meanwhile, the rs2070874 and rs2243250 SNPs of IL-4 were significantly associated with IVDD in Iranian patients.