Correlation Between Type Ⅰ Collagen Gene Polymorphism And Spinal Fusion Rate Following Autologous Bone Transplantation

Objective:To investigate the polymorphism of typeâ… collagen and to explore its relationship with the spinal fusion rate following metal implant or autogenous bone transplantation.Methods:A total of 200 volunteers who need to receive spinal fusion in the Affiliated Hospital of Qingdao University Medical College were selected, including 102 cases received anterior cervical subcorpectomy combined with iliac bone implantation fusion following decompression, and 98 cases received posterior laminectomy for decompression combined with intertransverse process fusion. Meantime,223 normal adults were served as the control group. The peripheral blood was drawn-off and genomic DNA was extracted from white blood cells. The specific fragment which includes the objective gene was amplified by polymerase chain reaction (PCR), with length of 293 bp. The genotypes of Pcol2 site in typeâ… collagen were detected by PCR-restriction fragment length polymorphism (PCR-RFLP) method. The PCR product was digested with restriction endonuclease Eco31I and the result was observed by agarose gel electrophoresis. The G gene represented for the presence of the restriction endonuclease site, while the T gene for the absence of the restriction endonuclease site. The fusion rate of the bone graft was evaluated by x-ray film prior to and at months 3,6 and 12 after operation, and the results were compared by stages including quick (<3 months), middle (3-6 months) and slow (6-12 months).Result:There were the-1997G/T polymorphisms of the type I collagen gene in 423 cases,166 cases were found the G/G homozygote at the position-1997 of coLIA1 gene, 232 cases with G/T, and 25 cases with T/T, in addition, there was some correlation between the G/G genotype and the iliac bone implantation fusion (P=0.004). The G/G genotype accounted for 50% in the fast group, which was obviously greater than that of the middle and slow groups (33.3% and 16.7%, respectively). However, the-1997G/T polymorphisms had no correlation with the bone graft fusions inter transverse process of lumbar vertebra (P=0.831).Conclusion:The G/G genotype in the-1997G/T polymophsim of the type I collagen gene may be the essential factor which can promote the C-spine auto-ilium graft fusion. We found no correlation between the polymorphism of the-1997 G/T and the bone graft fusions inter transverse process of lumbar vertebra. maybe it was caused by so many factors which interfere the fusion process.