ObjectiveTo demonstrate the project scope of the afferent nerves of the lumbar intervertebral disc,on which basis to explore the mechanism of the symptoms of discgenic low back pain.MethodsThirty Wistar rats were divided randomly into three groups of 10 rats each:the L4-5,L5-6,and L6 S1 group.Each group was further divided randomly into two subgroups,the experimental group and the control group,5 rats for each group.Intervertebral disc was exposed through the posterior approach under peritoneal cavity anesthesia,after the nerve roots were pull away,2 μl of 30％ cholera toxin-horseradish peroxidase (CT-HRP) was injected into the inner layer of the intervertebral disc in the experimental group,while 2 μl of 0.9％ Nacl was used in the control group.Forty-eight hours after the surgery,all rats were perfused and bilateral dorsal root ganglions(DRGs) of T10-L3 were resected and fixxied.Each DRG was sectioned at 30 μm thickness and processed by DAB method.The sections of DRGs were coverslipped and observed by optical microscopy for the neurons or axons labelled by CT-HRP.It was judged as positive that brownish-black particles were in the neurons or axons.ResultsNot in a single dorsal root ganglions,but in a scope of dorsal root ganglions axons labled by CT-HRP could be seen in the rats in the experimental groups.No CT-HRP labled neurons or axons were seen in dorsal root ganglions in the contral groups.ConclusionAfferent nerves of the lumbar intervertebral disc project to a scope of dorsal root ganglions,which is the anatomic basis of the mechanism of the symptoms of discgenic low back pain.