Study On Expression Of VEGF And BFGF In Intervertebral Disc Tissues Of Rabbits At The Age Of Different Months

Objective: To investigate the expression of the vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) in intervertebral disc tissue of rabbits at the ages of different months and find out whether VEGF and bFGF are related to degeneration of the intervertebral disc.Methods: (1) The 40 rabbits of 1, 3, 6, 9, 12, 18, 24 and 30 months old are divided into 8 groups on the basis of months old. There are 5 rabbits in every group. The rabbits of 1, 3 and 6 months old belong to minor month groups. And the rabbits of 9 and 12 months old belong to adult groups. The rabbits of 18, 24 and 30 months old belong to old groups. (2) Tissues from intervertebral discs(L5/L6,L6/L7,L7/S1) 40 rabbits are put into 4% polyoxymethylene 3 days. Then the tissues are put into methanoic acid for 7 days. After that the tissues are embed into paraffin and made for sections. (3) Sections from intervertebral discs tissues of rabbits were stained by haematoxylin eosin (HE) and immunohistochemical staining. (4) The histological changes and presence of bFGF and VEGF in intervertebral discs were observed by microscope. The IOD was obtained image analytical system.Results: (1) The results of HE staining:The structure of the minor months old rabbits'intervertebral discs is very clear. The annular fibrous of intervertebral discs is intact and compact. The form of collagen fibrils is in sequence. The verge between nucleus pulposus and annular fibrous is clear. The cells in nucleus pulposus are round or similar. The shape of theirs is small. And the quantity is very large. The structure of cartilage end plate is clear. The accrementition of cartilage corpuscle is very active. The annular fibrous of adult intervertebral discs is complete. The collagen fibrils of annular fibrous become larger and thicker than young intervertebral discs. And the number of cells is smaller than low months old rabbits. The collagen fibrils of old annular fibrous is in wild disorder. There are many crevices, fragmentations and deletions in annular fibrous. The condition will aggravate along with their months from low to high months. The collagen fibrils of nucleus pulposus are also in disorder. The degradation of nucleus pulposus matrix is very obvious. The cell cluster appears in nucleus pulposus. And there is a lot of matrix in the surrounding of cell cluster. The cartilage end plate is in wild disorder and calcification. (2) The expression of VEGF in rabbits'intervertebral discs:The expression of VEGF is positive in the surrounding of annular fibrous and the vascular endothelial cell of cartilage end plate. The expression of VEGF in adult rabbit becomes less than that in young rabbit. There are some positive cells mainly in the vascular endothelial cell of annular fibrous. And there is not nearly a positive cell in the nucleus pulposus of adult rabbit. The expression of VEGF increases along with the months of old rabbit from low to high months. It is positive in in the chondrocyte of nucleus pulposus and the mechanocyte of annular fibrous. Especially it is highly positive in the vascular endothelial cell of 30 months'intervertebral discs. (3) The expression of bFGF in rabbits'intervertebral discs:The expression of bFGF is very average in the surrounding of annular fibrous. And the expression of bFGF is positive in vascular endothelial cell. It is also positive in the vascular endothelial and chondrocyte cell of cartilage end plate. The expression of bFGF in the annular fibrous and cartilage end plate of adult rabbit becomes less than that in young rabbit. There is not nearly a positive cell in the nucleus pulposus of adult rabbit. The expression of bFGF in chondrocyte and mechanocyte increases along with the months of rabbit from low to high months. Especially it is highly positive in chondrocyte and vascular endothelial cell. It is also positive in the chondrocyte of nucleus pulposus. And the expression of bFGF increases along with the months of rabbit from low to high months. (4) The IOD of VEGF and bFGF in intervertebral disc tissue of 1 and 30 months old are 57.67 and 38.22, and 12 months old are 12.41 and 7.47. The IOD of young and old months are very different from adult months'(P<0.01). Conclusion: (1) The structure of intervertebral disc varies from growth, mature to degeneration along with their months. (2) Both the expression of VEGF and bFGF decrease also changes along with their months. And they are very similar. (3) The expression of VEGF and bFGF is very similar with the change of intervertebral discs'structure. The IOD of VEGF and bFGF in intervertebral disc tissue are related with the growth, mature to degeneration of intervertebral disc.