Changes induced by hyperosmotic mannitol in cerebral endothelial cells: an atomic force microscopic study.
Understanding the reaction of living cells in response to different extracellular stimuli, such as hyperosmotic stress, is of primordial importance. Mannitol, a cell-impermeable non-toxic alcohol, has been used successfully for reversible opening of the blood-brain barrier in hyperosmotic concentrations. In this study we analyzed the effect of hyperosmotic mannitol on the shape and surface structure of living cerebral endothelial cells by atomic force microscope imaging technique. Addition of clinically relevant concentrations of mannitol to the culture medium of the confluent cells induced a decrease of about 40% in the observed height of the cells. This change was consistent both at the nuclear and peripheral region of the cells. After mannitol treatment even a close examination of the contact surface between the cells did not reveal gap between them. We could observe the appearance of surface protrusions of about 100 nm. By force measurements the elasticity of the cells were estimated. While the Young's modulus of the control cells appeared to be 8.04 +/- 0.12 kPa, for the mannitol-treated cells it decreased to an estimated value of 0.93 +/- 0.04 kPa which points to large structural changes inside the cell.
Bálint
Zoltán
Z
Institute of Biophysics, Biological Research Center of Hungarian Academy of Sciences, Temesvari krt 62, Szeged 6726, Hungary.
Krizbai
István A
IA
Wilhelm
Imola
I
Farkas
Attila E
AE
Párducz
Arpád
A
Szegletes
Zsolt
Z
Váró
György
G
D000818:Animals; D001921:Brain / Q000166:cytology / Q000187:drug effects* / Q000502:physiology*; D048429:Cell Size / Q000187:drug effects; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004548:Elasticity; D042783:Endothelial Cells / Q000166:cytology / Q000187:drug effects* / Q000502:physiology*; D008353:Mannitol / Q000008:administration & dosage*; D008560:Membrane Fluidity / Q000187:drug effects* / Q000502:physiology; D018625:Microscopy, Atomic Force / Q000379:methods*; D009997:Osmotic Pressure / Q000187:drug effects; D051381:Rats; D013314:Stress, Mechanical
D008353:Mannitol