Glutaraldehyde mediated echinocyte/discocyte transformation is Ca2+ dependent

Area of Science:

• Hematology
• Cell Biology
• Biochemistry

Background:

• Erythrocytes (red blood cells) can adopt various shapes, including echinocytes (spiky) and discocytes (biconcave).
• Glutaraldehyde is a chemical fixative used in microscopy and histology.

Purpose of the Study:

• To investigate the rapid shape transformation of echinocytes to discocytes induced by glutaraldehyde.
• To explore the underlying mechanisms and factors influencing this glutaraldehyde-induced erythrocyte shape change.

Main Methods:

• Production of echinocytes from banked blood via repeated washing in phosphate-buffered saline.
• Incubation of echinocytes in isotonic and hypertonic glutaraldehyde solutions.
• Measurement of cell volume, critical hemolysis volume, cellular deformability, and potassium (K+) efflux.
• Assessment of the effects of trypsination, osmolarity, and chelating agents (with calcium addition) on the transformation.

Main Results:

• Echinocytes rapidly transformed into discocytes within 30 seconds in isotonic 0.05% glutaraldehyde (pH 7.4).
• This transformation did not alter cell volume or critical hemolysis volume but decreased deformability and increased K+ efflux, indicating membrane damage.
• Trypsination did not inhibit the shape change.
• Hypertonic glutaraldehyde partially inhibited the transformation.
• Chelating agents completely inhibited the transformation, an effect reversed by adding calcium ions (Ca2+).

Conclusions:

• Glutaraldehyde induces a rapid echinocyte-to-discocyte transformation in erythrocytes.
• The process involves alterations in cell membrane permeability and potassium efflux, suggesting membrane damage.
• Calcium ions are implicated in the glutaraldehyde-stimulated transformation, though the precise mechanism remains elusive.