【Abstract】 Objective To explore the role of activin A mediated apoptosis in patients with lumbar disc vacuum degeneration. Methods The expression of activin A protein and mRNA in the nucleus pulposus of patients with lumbar disc vacuum degeneration was measured. The isolated human lumbar intervertebral disc nucleus pulposus cells were randomly divided into Control group, Activin A group and Activin A+follistatin group. The proliferation, apoptosis and expression of related proteins were detected after 48 hours of culture. Results The expression of activin A protein and mRNA in nucleus pulposus of patients with lumbar disc vacuum degeneration was higher than that of control group (both P<0. 001). The expression of p-Smad3 protein, the inhibition rate of cell proliferation, apoptosis rate, the expression of Bax and Active caspase 3 protein in activin A group were higher than those in control group (all P<0. 001) , while the expression of Bcl-2 protein was lower than that in control group (P<0. 001). Follistatin could inhibit the above biological effects of activin A to some extent (all P<0. 001). Conclusion Activin A is highly expressed in patients with lumbar intervertebral disc vacuum degeneration. Activin A can activate the Smad3 signaling pathway, inhibit the proliferation of nucleus pulposus cells and induce nucleus pulposus cells apoptosis through mitochondrial apoptosis pathway. Follistatin can antagonize the pro-apoptotic effect of activin A, which provides a new idea for lumbar disc vacuum degeneration.