Objective: To observe the effect of "Weizhong"(BL 40) bleeding on sciatic nerve conduction velocity(SNCV) and interleukin-1α(IL-1α) content of the lumbar vertebral nucleus pulposus tissue in experimental lumbar intervertebral disc protrusion(LIDP) rabbits so as to explore the underlying mechanism of blood letting in the treatment of LIDP.Methods: Forty healthy New Zealand rabbits were randomly assigned to control

model

BL40 and non-point(1 cm medial to BL 40) groups

with 10 cases in each group.LIDP model was established by pushing the intervertebral disc tissue rightward to protrude the posterior longitudinal ligament with a self-made instrument after exposing the L6-7 vertebrae and intervertebral space.Blood-letting was performed at "Weizhong"(BL 40) and non-point by using a triangle-edged needle to prick the local tissue

once daily and continuously for 7 days.SNCV was detected by using BL-410 physiological signal recording system

and the content of IL-1α in L6-7 intervertebral disc tissue determined with enzyme linked immunsorbent assay(ELISA).Results: In comparison with control group and pre-modeling

SNCV decreased significantly in model

BL40 and non-acupoint groups after LIDP;while compared with model group

values of SNCV in BL40 group increased considerably(P<0.05)

no significant changes were found between non-acupoint group and model group(P>0.05).Compared with control group

the contents of IL-1α in the nucleus pulposus in model and non-acupoint groups increased remarkably(P<0.05

0.01)

but no significant difference was found between control and BL40 groups in IL-1α level(P>0.05).Conclusion: Blood-letting at "Weizhong"(BL 40) can relieve LIDP-induced nerve injury and mechanical oppression to improve SNCV

which may be closely related to its effect in decreasing inflammatory factor IL-1α level.