Fig. 3.

Observations of the morphological ultrastructural appearance by TEM. The IVD cells exposed to saline displayed a nearly normal cell morphology, including plasma membrane integrity, abundant surrounding microvilli, and slight swelling of organelles. The IVD cells exposed to 0.5% bupivacaine showed typical necrotic morphological changes, including severe swelling of organelles, severe disruption of the plasma membrane, and cellular lysis. AF, annulus fibrosus; NP, nucleus pulposus; B, bupivacaine.