[The effect in vitro of glucose on erythrocyte resistance to hemolysis]

The resistance of erythrocytes to hemolysis is a measurable indicator of the sensitivity of these cells to the action of hemolytic factors. A normal, chemically unmodified red blood cell demonstrates significant resistance against hypo-osmotic solutions of NaCl or detergents like saponin. It has recently been reported that glucose participates in the function of the erythrocyte wall and modifies sensitivity towards hemolytic factors. This work was undertaken to examine the effect of short-term hyperglycemia on saponin and osmotic resistance of erythrocytes.

Peripheral blood erythrocytes were obtained from 25 healthy individuals (12 females and 13 males) aged 28 to 54 years. Erythrocytes were incubated for 90 min at 37 degrees C in glucose solutions: < 5 mmol/L (control group), 6.66 and 9.99 mmol/L (study groups). Osmotic resistance (NaCl solutions from 10 to 150 mmol/L) and saponin resistance (saponin from 5 to 35 mg/L) was followed with a spectrophotometer. We calculated F50 representing the concentration of NaCl or saponin producing hemolysis of 50% of the erythrocyte population. Concentrations of extracellular hemoglobin were determined spectrophotometrically with Drabkin's reagent. Statistical analysis was done with Statistica 6.1 (StatSoft, Krakow) software and Student's t-test for paired results was applied. Statistical significance was taken as p < 0.05.

We found that mean concentrations of NaCl or saponin producing lysis of 50% of erythrocytes (F50) and concentrations of extracellular hemoglobin changed significantly with rising concentration of glucose in the incubation medium.

Glucose affected the osmotic and saponin resistance. Short-term hyperglycemia decreased the resistance of erythrocytes against osmotic factors and increased saponin resistance.