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Lidocaine induces ROCK‐dependent membrane blebbing and subsequent cell death in rabbit articular chondrocytes
Author(s) -
Maeda Tsutomu,
Toyoda Futoshi,
Imai Shinji,
Tanigawa Hitoshi,
Kumagai Kousuke,
Matsuura Hiroshi,
Matsusue Yoshitaka
Publication year - 2016
Publication title -
journal of orthopaedic research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.041
H-Index - 155
eISSN - 1554-527X
pISSN - 0736-0266
DOI - 10.1002/jor.23092
Subject(s) - lidocaine , bleb (medicine) , viability assay , chemistry , rhoa , rho associated protein kinase , pharmacology , extracellular , fasudil , programmed cell death , microbiology and biotechnology , cell , medicine , andrology , anesthesia , apoptosis , biology , kinase , surgery , biochemistry , signal transduction , intraocular pressure , trabeculectomy
ABSTRACT Local anesthetics are administered intraarticularly for pain control in orthopedic clinics and surgeries. Although previous studies have shown that local anesthetics can be toxic to chondrocytes, the underlying cellular mechanisms remain unclear. The present study investigates acute cellular responses associated with lidocaine‐induced toxicity to articular chondrocytes. Rabbit articular chondrocytes were exposed to lidocaine and their morphological changes were monitored with live cell microscopy. The viability of chondrocytes was evaluated using a fluorescence based LIVE/DEAD assay. Acute treatment of chondrocytes with lidocaine (3–30 mM) induced spherical protrusions on the cell surface (so called “membrane blebbing”) in a time‐ and concentration‐dependent manner. The concentration‐response relationship for the lidocaine effect was shifted leftward by elevating extracellular pH, as expected for the non‐ionized lidocaine being involved in the bleb formation. ROCK (Rho‐kinase) inhibitors Y‐27632 and fasudil completely prevented the lidocaine‐induced membrane blebbing, suggesting that ROCK activation is required for bleb formation. Caspase‐3 levels were unchanged by 10 mM lidocaine ( p = 0.325) and a caspase inhibitor z‐VAD‐fmk did not affect the lidocaine‐induced blebbing ( p = 0.964). GTP‐RhoA levels were significantly increased ( p < 0.001), but Rho inhibitor‐1 failed to suppress the membrane blebbing ( p = 0.875). Lidocaine (30 mM) reduced the cell viability of isolated chondrocytes ( p < 0.001) and in situ chondrocytes ( p < 0.001). The chondrotoxicity was attenuated by pretreatment of cells with ROCK inhibitors or a myosin‐II inhibitor blebbistatin ( p < 0.001). These findings suggest that lidocaine induces ROCK‐dependent membrane blebbing and thereby produces a cytotoxic effect on chondrocytes. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:754–762, 2016.