ABSTRACT
Objective To explore the effects of gravitational traction and target regulation of caspase3 on the degenerative intervertebral disc cells in rabbits.Methods Rabbits nucleus pulposus cells transfected with caspase3 siRNA or negative control siRNA were incubated in serum-starved medium for 6 hours and 48 hours.The expression of caspase3 siRNA and cell apoptosis were analyzed by RT-qPCR and Annexin V-fluorescein staining.In order to create intervertebral disc degeneration model,the right anterior side of the annulus fibrosus of lumbar vertebrae of 35 rabbits were damaged by 16-gauge needle.After confirming the success of modeling,35 animal models were randomized into 3 groups:model group (n=10),negative siRNA group (n=10) and caspase3 siRNA group (n=5).Either negative control siRNA or caspase3 siRNA was injected into the center of nucleus pulposus using a 26-gauge needle from the left anterior side,while the model group received no injection.Nucleus pulposus tissue of 5 rabbits selected randomly from every group after 48 hours were analyzed by PCR and Western blotting for caspase3 mRNA and protein expressions.Half of the casepase3 siRNA group were selected randomly and received a routine gravitational traction using a model of our own design,30min per day for 2 weeks,while other groups received no treatment.TNF-o and IL-1β expression levels and histopathological observations were performed after intervention.Results Expression of caspase3 mRNA in rabbit nucleus pulposus cells transfected with caspase3 siRNA decreased obviously in serum-starved medium,and the apoptosis rate of cells cultured in serum-starved medium decreased significantly (P＜0.05).Caspase3 mRNA and caspase3 protein expression of nucleus pulposus injected by caspase3 siRNA down-regulated in the caspase3 siRNA group.Compared with model group and negative control siRNA group,TNF-α and IL-1β expression levels of caspase3 siRNA traction group decreased significantly (P＜0.05),but there was no statistical significance compared with caspase3 siRNA group (P＞0.05).Pathological observation revealed that viable cell number and extracellular matrix contents increased and collagenous fibers arranged regularly in caspase3 siRNA traction group.Conclusion Gravitational traction and target regulation of caspase3 can prevent apoptotic cell death and delay early intervertebral disc degeneration.