RBC
Morphological Perturbation of Human Erythrocytes Exposed to Photoilluminated Riboflavin
Tue, 2015-09-15 11:25 — Iyad AliBackground: Reactive oxygen species (ROS) are formed as a natural byproduct of the normal metabolism of oxygen and have important roles in cell signaling and homeostasis.
However, during times of oxidative stress, ROS levels can rise
dramatically. This may result in significant damage to cell structures.
In this work we are interested to show the effect of different ROS on
the morphology of fresh human RBCs.
Methods: The RBCs
were incubated with different reaction mixtures at room temperature and
exposed to cool fluorescent light (800 lux). Then, cells were isolated
and scanned by a scanning electron microscope.
Results:
When incubated with photoilluminated riboflavin, RBCs lost their
biconcave shape and adopted a spherocytes shape. The formation of
spherocytes is usually associated with spectrin deficiency. In the
presence of Cu(II) and riboflavin, RBCs appeared with spikes of
different sizes on their surface showing the formation of
“acanthocytes”, which is usually prevalent in abetalipoprotienemia.
Moreover, addition of NaN3 to riboflavin-Cu(II) system resulted in
completely damaged RBCs. Away from the above combinations, when RBCs
are incubated with riboflavin-aminophylline combination, they appeared
with spikes of equal lengths and sizes on their surface “echinocytes”,
which usually appear in different diseases like pyruvate kinase
deficiency and uremia.
Conclusion: Red blood cells
undergo different morphological changes when incubated in each of the
above combinations, most probably due to the formation of different ROS
and these ROS could be involved in different pathological consequences.
Facebook
Google
LinkedIn
TwitterHemolysis of Human Red Blood Cells by Combination of Riboflavin and Aminophylline
Tue, 2011-02-22 11:21 — Iyad AliThe effect of aminophylline on human red blood cells (RBC) has been studied. Under in vitro condition, aminophylline alone does not hemolyse RBC. However, in the presence of riboflavin and visible light, aminophylline causes hemolysis of RBC. This hemolysis depends on the concentration of both riboflavin and aminophylline. Using different free radical scavengers we show that RBC hemolysis is caused by reactive oxygen species. Studies using bovine serum albumin show that riboflavin-aminophylline combination can also cause protein degradation in vitro.
Hemolysis of Human Red Blood Cells by Riboflavin-Cu(II) System: Enhancement by Azide
Tue, 2011-02-22 11:18 — Iyad AliPhotoactivated riboflavin in the presence of Cu(II) generates reactive oxygen species (ROS) which can hemolyze human red blood cells (RBC). In the present work we examined the effect of sodium azide (NaN3) on RBC in the presence of riboflavin and Cu(II). The addition of NaN3 to the riboflavin-Cu(II) system enhanced K+ loss and hemolysis. The extent of K+ loss and hemolysis were time and concentration dependent. Bathocuproine, a Cu(I)-sequestering agent, inhibited the hemolysis completely. Among various free radical scavengers used to identify the major ROS involved in the reaction, thiourea was found to be the most effective scavenger. Thiourea caused almost 85%inhibition of hemolysis suggesting that ·OH is the major ROS involved in the reaction. Using spectral studies and other observations, we propose that when NaN3 is added to the riboflavin-Cu(II) system, it inhibits the photodegradation of riboflavin resulting in increased ·OH generation. Also, the possibility of azide radical formation and its involvement in the reaction could not be ruled out.
