title: Cytometric analysis of lidocaine-induced cytotoxicity: a model experiment using rat thymocytes.
abstract: Lidocaine is a local anesthetic possessing both lipophilic and hydrophilic properties. It also acts as a surfactant. Thus, the disruption of membranes, resulting in necrosis, is one of possible mechanisms for lidocaine-induced cytotoxicity. However, lidocaine is reported to induce apoptosis. Therefore, in order to compare two mechanisms for cell death induced by lidocaine, the effects of millimolar lidocaine were examined on rat thymocytes by a flow cytometer with appropriate fluorescent probes. Lidocaine decreased the population of living cells with phosphatidylserine-exposed membranes, one of markers for early stage of apoptosis, and increased the population of dead cells without increasing that of cells with hypodiploidal DNA. Lidocaine at millimolar concentrations may deteriorate the membranes of such apoptotic living cells rather than those of intact living cells, resulting in necrosis. It is suggested that the process of apoptosis is not completed in the presence of millimolar lidocaine.
authors.affiliation: Laboratory of Cellular Signaling, Faculty of Integrated Arts and Sciences, The University of Tokushima, Tokushima 770-8502, Japan.
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Nishimura
authors.forename: Aimi
authors.initials: A
authors.lastname: Kanada
authors.forename: Jun-ya
authors.initials: JY
authors.lastname: Yamaguchi
authors.forename: Kanna
authors.initials: K
authors.lastname: Horimoto
authors.forename: Masako
authors.initials: M
authors.lastname: Kobayashi
authors.forename: Tomoko
authors.initials: T
authors.lastname: Tatsuishi
authors.forename: Kaori
authors.initials: K
authors.lastname: Kanemaru
authors.forename: Shin-ya
authors.initials: SY
authors.lastname: Ueno
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Oyama
mesh_terms: D000779:Anesthetics, Local / Q000009:adverse effects*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D048429:Cell Size / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D005434:Flow Cytometry; D008012:Lidocaine / Q000009:adverse effects*; D008297:Male; D008954:Models, Biological; D051381:Rats; D017208:Rats, Wistar; D013950:Thymus Gland / Q000187:drug effects / Q000473:pathology*
chemical_list: D000779:Anesthetics, Local; D008012:Lidocaine