Basic and Translational Science In Vitro and In Vivo Effect of Lidocaine on Rat Muscle-Derived Cells for Treatment of Stress Urinary Incontinence Dae Kyung Kim, Ron J. Jankowski, Ryan Pruchnic, Fernando de Miguel, Naoki Yoshimura, Masashi Honda, Akira Furuta, and Michael B. Chancellor OBJECTIVES Lidocaine cytotoxicity has been reported in some cell types, which could affect its use as a local anesthetic in cell-based therapy. We evaluated the in vitro and in vivo effect of lidocaine on rat muscle-derived progenitor cells (MDCs). METHODS MDCs were isolated from rat skeletal muscle and purified using the preplate technique. For in vitro tests, the MDCs underwent either 2 hours of, or continuous, exposure to lidocaine (50 M-5 mM). After 72 hours of incubation, cell viability was measured using the methylthiazo- loletetrazolium assay. For the in vivo tests, periurethral injection of either phosphate-buffered saline, MDCs (1  10 6 cells/20 L), or 2% lidocaine plus MDCs was performed in pudendal nerve-transected rats. The leak point pressure (LPP) was measured at 4 weeks after the injection. RESULTS Lidocaine concentrations of 500 M had no effect on MDCs with continuous exposure. MDCs in 1 mM lidocaine showed decreased survival and no MDCs in 5 mM lidocaine survived. With a 2-hour exposure, only MDCs in the 5-mM lidocaine group showed decreased survival. Rats with nerve transection and phosphate-buffered saline injection showed significantly lower LPPs than the controls. The LPP was restored to a significantly greater level after MDCs only or lidocaine plus MDC injection. No statistically significant difference in LPP restoration was found between the MDC-only and lidocaine plus MDC injections. CONCLUSIONS Cytotoxicity to lidocaine was minimal at a physiologic concentration in vitro. The functional recovery of LPP by MDC treatment was not affected by lidocaine preinfiltration. Taken together, our data indicate that lidocaine can be applied as a local anesthetic in periurethral MDC injection without decreasing the efficacy of the therapy. UROLOGY 73: 437– 441, 2009. © 2009 Elsevier Inc. L idocaine has been widely used as a regional or local anesthetic agent since its development in 1943. However, from reports of cauda equina syndrome and transient neurologic symptoms after spinal or epi- dural anesthesia, lidocaine’s possible neurotoxicity was noted in the late 1990s. 1-3 Several in vitro studies have demonstrated that lidocaine-induced cell death was me- diated by disturbances in cytoplasmic calcium ion ho- meostasis and mitochondrial injury in neuronal cells. 4,5 Lidocaine can also be toxic to other cells such as the corneal epithelial cells, 6 urothelial cells, 7 pneumocytes, 8 and chondrocytes. 9 The cellular toxicity of lidocaine could be detrimental to cell-based therapy, limiting its use as a local anesthetic. In previous studies, we have demonstrated that the periurethral injection of muscle-derived cells (MDCs) increased urethral sphincteric contractility in a stress urinary incontinence (SUI) animal model. 10,11 To date, no reports have been published regarding the possible cytotoxic effects of lidocaine on MDCs. In the present study, we evaluated the potential in vitro cytotoxicity of lidocaine to rat MDCs and investigated the in vivo functional effects after adding lidocaine preinfiltration in the periurethral injection of MDCs. MATERIAL AND METHODS MDC Preparation Rat MDCs were harvested from the gastrocnemius muscle of normal female Sprague-Dawley rats and purified using the pre- plate technique. 12 In brief, the muscle biopsy was removed from the hind limb and minced into coarse slurry using successively smaller needles. The minced muscle tissues were enzymatically dissociated using 0.2% collagenase-type XI, grade II dispase 240 This study was supported by a grant from the National Institutes of Health (DK 055045). From the Department of Urology, Eulji University, Daejeon, Republic of Korea; Cook-Myosite, Incorporated, Pittsburgh, Pennsylvania; Department of Urology, Uni- versity of Pittsburgh, Pittsburgh, Pennsylvania; and Department of Urology, William Beaumont Hospital, Royal Oak, Michigan Reprint requests: Michael B. Chancellor, M.D., Department of Urology, William Beaumont Hospital, 438 Medical Office Building, 3535 West 13 Mile Road, Royal Oak, MI 48073. E-mail: michael.chancellor@beaumont.edu Submitted: April 21, 2008, accepted (with revisions): June 2, 2008 © 2009 Elsevier Inc. 0090-4295/09/$34.00 437 All Rights Reserved doi:10.1016/j.urology.2008.06.019