title: Poloxamer 188 enhances functional recovery of lethally heat-shocked fibroblasts.
abstract: Damage to the cell membrane has been implicated as the primary event in the pathogenesis of heat shock, generally resulting in loss of cellular homeostasis and cell death. Thus a promising mode of therapy would involve the restoration of cell membrane integrity. Surfactant molecules, specifically triblock polymers such as Poloxamer 188 (P-188), possess the ability to self-aggregate into membrane-like structures in aqueous solutions and have been shown to restore membrane integrity. The objective of this study was to develop functional and morphological assays to determine whether treatment with P-188 after heat shock enhances the recovery of thermally damaged cells. Human foreskin fibroblasts were placed in sterile vials and heated by immersion in a calibrated water bath for various lengths of time at predefined temperatures. Cell recovery after heat shock was assessed using a functional assay based on the ability of the cells to contract fibroblast populated collagen lattices (FPCLs). Subsequent to heating, collagen lattices were prepared with control (no heat, no P-188) and heat shocked cells (with and without P-188). Our results indicate that treatment with low concentrations of P-188 after heat shock was effective in ameliorating both the morphological integrity and the contractile function of thermally damaged cells. Further, we observed that P-188 was most effective in improving the contractile ability of cells heat shocked at 45 degrees C; however, it had no influence on the contractility of cells exposed to higher temperatures. Our results suggest that there exists a threshold of thermal stress (45 degrees C for 20-60 min) beyond which treatment with low concentrations of P-188 (0.5 mg/ml) is ineffective in minimizing cell damage. Moreover, the results of our morphological assays indicate that cells treated with P-188 after heat shock maintain their cytoskeletal organization, whereas untreated cells exhibit filamentous actin depolymerization.
authors.affiliation: Center for Engineering in Medicine and Surgical Services, Massachusetts General Hospital, Boston, USA.
authors.forename: F A
authors.initials: FA
authors.lastname: Merchant
authors.forename: W H
authors.initials: WH
authors.lastname: Holmes
authors.forename: M
authors.initials: M
authors.lastname: Capelli-Schellpfeffer
authors.forename: R C
authors.initials: RC
authors.lastname: Lee
authors.forename: M
authors.initials: M
authors.lastname: Toner
mesh_terms: D008841:Actin Cytoskeleton / Q000187:drug effects / Q000473:pathology; D002460:Cell Line; D002470:Cell Survival; D003094:Collagen / Q000378:metabolism; D003599:Cytoskeleton / Q000187:drug effects / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D005347:Fibroblasts / Q000166:cytology / Q000502:physiology; D018869:Heat-Shock Response / Q000502:physiology*; D006358:Hot Temperature; D006801:Humans; D008297:Male; D011060:Poloxalene / Q000494:pharmacology*; D012879:Skin Physiological Phenomena / Q000187:drug effects*; D013501:Surface-Active Agents / Q000494:pharmacology*
chemical_list: D013501:Surface-Active Agents; D011060:Poloxalene; D003094:Collagen