The direct interaction of hyaluronic acid (HA) and heavy chain (HC) of the
inter-alpha-trypsin inhibitor (I alpha I) family plays a critical role in t
he organization and stabilization of the extracellular matrix. The aim of t
he present investigation was to elucidate the distribution of the I alpha I
HC and HA in adult mouse tissues. An immunohistochemical method using a ra
bbit polyclonal antibody raised against mouse I alpha I heavy-chain peptide
and a specific probe for HA (biotinylated HA-binding protein) was used to
demonstrate an immunolocalization of I alpha I HC and HA. Distribution and
localization of HA was of three types, namely, colocalization with I alpha
I HC itself (cartilaginous tissue and ovary), localization around I alpha I
HC immunostaining (lung, intestine and skeletal muscle), and localization
at a small distance from I alpha I HC or a different distribution pattern (
brain, liver, skin and kidney). These results indicate that I alpha I HC co
uld function as an HA-rich matrix stabilizer on the cells of cartilage and
maturing ovary, in which I alpha I HC shows colocalization with its predomi
nant ligand, HA.