Bone decalcification is the softening of bones due to the removal of calcium ions, and can be performed as a histological technique to study bones and extract DNA.
This process also occurs naturally during bone development and growth, and when uninhibited, can cause diseases such as
osteomalacia
Osteomalacia is a disease characterized by the softening of the bones caused by impaired bone metabolism primarily due to inadequate levels of available phosphate, calcium, and vitamin D, or because of resorption of calcium. The impairment of bone ...
.
Histology
Since calcium-rich bones are exceedingly difficult to study, scientists use bone decalcification to make specimens available for their research.
For example, bone decalcification has been used to examine
cartilage
Cartilage is a resilient and smooth type of connective tissue. In tetrapods, it covers and protects the ends of long bones at the joints as articular cartilage, and is a structural component of many body parts including the rib cage, the neck an ...
and
magnesium levels in order to understand bone decay.
There are two categories of decalcifying agents for removing calcium ions:
chelating agents
Chelation is a type of bonding of ions and molecules to metal ions. It involves the formation or presence of two or more separate coordinate bonds between a polydentate (multiple bonded) ligand and a single central metal atom. These ligands are ...
and acids. The acids are further divided into weak (picric, acetic and formic acid) and strong acids (nitric and hydrochloric acid). The acids help produce a solution of calcium ions while the chelating agents take up the calcium ions. The most frequently used chelating agent is
Ethylenediaminetetraacetic acid
Ethylenediaminetetraacetic acid (EDTA) is an aminopolycarboxylic acid with the formula H2N(CH2CO2H)2sub>2. This white, water-soluble solid is widely used to bind to iron (Fe2+/Fe3+) and calcium ions (Ca2+), forming water-soluble complexes eve ...
(EDTA). Decalcification is a lengthy procedure, as bone pieces have to be left in the decalcifying agent for days to weeks, depending on the size of the bone. There are numerous methods to test when bone decalcification is complete, such as X-ray examination, chemical analysis, and measurement of specimen flexibility. Decalcification is necessary to obtain soft sections of the bone using a
microtome
A microtome (from the Greek ''mikros'', meaning "small", and ''temnein'', meaning "to cut") is a cutting tool used to produce extremely thin slices of material known as ''sections''. Important in science, microtomes are used in microscopy, allow ...
. Every thin section of the bone that is cut can be processed (see
tissue processing) like any other soft tissue of the body.
See also
*
Bone seeker
References
{{DEFAULTSORT:Bone Decalcification
Anatomical pathology
Bones
Calcium