Association between the expression of Aggrecan and the distribution of Aggrecan gene variable number of tandem repeats with symptomatic lumbar disc herniation

Abstract

To study the expression of Aggrecan and the relationship between the variable number of tandem repeats (VNTR) of Aggrecan and lumbar disc herniation (LDH). The disease group comprised of 74 patients already diagnosed with symptomatic LDH. The control group consisted of 15 patients restricted to spinal trauma and 113 healthy blood donors without symptoms of LDH who were not diagnosed with LDH. Disc tissue samples were obtained from surgical operations and blood samples were donated from all participants. The Aggrecan expression in isolated tissues was assessed by western blot using specific antibodies. The Aggrecan gene VNTR region was analyzed by PCR. The Aggrecan expression positive rate of control group was statistically and significantly higher (control group:86.67%, disease group:13.51%;χ(2) = 34.83, P < 0.05) than that of the disease group. Moreover, there was a statistically significant higher frequency of Allele 25 or Allele 21 in disease group compared to controls (A25disease group = 22.97%, A25control group = 12.11%, χ(2)A25 = 8.20, PA25 = 0.004; A21disease group = 6.76%, A21control group = 0.39%, χ(2)A21 = 14.35, PA21 = 0.000). Compared to the participants with 2 Alleles>25 repeats, subjects with 1 or 2 Alleles ≤ 25 repeats statistically and significantly over represented the disease group without the expression of Aggrecan (χ(2) = 5.69, P = 0.017). The findings suggest a relationship between Aggrecan and symptomatic LDH, where symptomatic LDH has a tendency of allele 21 and allele 25 repeats.In addition, an association between the distribution of Aggrecan gene VNTR polymorphism and the expression of Aggrecan is observed in symptomatic LDH.