Expression of HSPA8 in Nucleus Pulposus of Lumbar Intervertebral Disc and Its Effect on Degree of Degeneration.

INTRODUCTION: This study aimed to investigate the expression of a 70-kDa heat shock protein [heat shock 70-kDa protein 8 (HSPA8)/heat shock protein 70 (Hsc70)] in human degenerative lumbar intervertebral discs and its relationship with the degree of degeneration of human intervertebral discs. METHODS: A total of 72 cases of lumbar intervertebral disc nucleus pulposus tissues were collected. Among these, 18 cases of nucleus pulposus tissue were assigned to the control group, while 54 cases of nucleus pulposus tissues were assigned to the experimental group. According to the preoperative MRI, cases in the experimental group were further divided into three groups: protrusion group (n = 18), extrusion group (n = 18), and sequestration group (n = 18). Western blot was performed to determine the relative expression of HSPA8 in the nucleus pulposus in each group. Hematoxylin and eosin staining was performed to determine the number of nucleus pulposus cells, morphological differences, and cell densities of the degenerated intervertebral discs and normal intervertebral discs. Immunohistochemistry was performed to determine the expression of HSPA8 in nucleus pulposus tissues in each group. RESULTS: Hematoxylin and eosin staining results: There were significant differences in cell morphology and number between the control group and the experimental group. Furthermore, there were significant differences in cell density (F = 936.80, P < 0.01). Immunohistochemistry results: HSPA8 was expressed in lumbar intervertebral disc nucleus pulposus tissues, and its expression of gradually decreased with the severity of the disease, and the differences were significant (F = 2110.43, P < 0.01). Western blot results: The expression of HSPA8 in human degenerative nucleus pulposus tissues gradually decreased, and the differences were significant (F = 1841.72, P < 0.01). CONCLUSION: HSPA8 is stably expressed in human intervertebral disc nucleus pulposus tissues, and its expression is associated with the degree of intervertebral disc degeneration.

The research of transgenic human nucleus pulposus cell transplantation in the treatment of lumbar disc degeneration.

The present study determines whether the in vivo injection of TGFß1 and CTGF mediated by AAV2 to transfect nucleus pulposus cells in degenerative lumbar discs can reverse the biological effects of rhesus lumbar disc degeneration. A total of 42 lumbar discs obtained from six rhesus monkeys were classified into three groups: experimental group, control group, and blank group. Degenerative lumbar discs were respectively injected with double gene-transfected human nucleus pulposus cells using minimally invasive techniques. Immumohistochemical staining, RT-PCR, and western blot were performed to observe the biological effects of double gene-transfected human nucleus pulposus cells in degenerative lumbar discs on rhesus lumbar disc degeneration. At 4, 8, and 12 weeks after the transplantation of nucleus pulposus cells, the expression levels of TGF-ß1, CTGF, proteoglycan mRNA, and type-II collagen were detected by RT-PCR. The values of immumohistochemical staining and RT-PCR in the experimental group increased at 8 weeks, decreased with time at 12 weeks, and remained greater than the values in the control group, and the differences were statistically significant (P < .05). The western blot revealed that the values in the experimental group decreased with time, but remained greater than those in the PBS control group and blank control group, and the differences were statistically significant (P < .05). The double gene-transfection of human nucleus pulposus cells in degenerative lumbar discs mediated by rAAV2 can be continuously expressed in vivo after transplantation in lumbar discs of rhesus monkeys, and promotes the synthesis of proteoglycan and type II collagen, achieving the treatment purpose.