A new discovery has revealed that haemoglobin isn’t used by RBCs alone and has reported that ‘chondrocytes’ – cells that make cartilage, the connecting tissue between bones – also make haemoglobin and seem to depend on it for their survival.
Haemoglobin is an iron-containing protein in the blood of animals that transports oxygen to the tissues.
It is present in RBCs of vertebrates. All vertebrates except cold-water ice fish transport oxygen via haemoglobin.
Haemoglobin forms an unstable reversible bond with oxygen.
In oxygenated state, it is called oxyhemoglobin (bright red) and in reduced state it is called deoxyhemoglobin (purple-blue).
Haemoglobin develops in cells in bone marrow that become RBCs.
RBC (aka erythrocytes) carries oxygen from lungs to every cell in body.
RBC is covered with a membrane composed of proteins and lipids, lacks a nucleus, and contains haemoglobin.
Points from the research:
The researchers observed spherical structures, termed "haemoglobin bodies" or Hedy, within chondrocytes that contained haemoglobin.
These structures were crucial for the survival of chondrocytes. When the gene responsible for haemoglobin production was removed in mice, leading to a lack of haemoglobin, the chondrocytes died.
The haemoglobin in chondrocytes appears to serve as an oxygen store, releasing oxygen when needed in low-oxygen environments.
This finding challenges previous notions about how chondrocytes adapt to low oxygen levels, shedding light on a new mechanism for their survival in regions with limited blood supply.
Additionally, haemoglobin was also found in cartilage outside of growth plates, such as in the ribs and spine of mice, though its exact function in these regions remains to be determined.
Functions of Chondrocytes:
It releases substances to make cartilage strong yet flexible.
Haemoglobin in Chondrocytes carries oxygen and is essential for their survival.
Haemoglobin in the chondrocytes stores oxygen and supplies it to the cells when required.
Haemoglobin Associated Diseases:
Sickle Cell Anaemia: Haemoglobin S is a variant form of haemoglobin that is present in persons who have Sickle Cell Anaemia (SCA).
SCA is a severe hereditary form of anaemia in which cells become crescent-shaped when oxygen is lacking.
Thalassemia: A group of inherited blood disorders characterized by a deficiency of haemoglobin.