Expression and Immunohistochemical Localisation of the Gβγ-activated and Calcineurin-Inhibited Adenylyl Cyclase Isoforms in Rat Articular Chondrocytes.

OBJECTIVE

To determine the expression and localisation of the Gβγ-activated adenylyl cyclase (AC) isoforms 2, 4, and 7 and calcineurin-inhibited AC isoform 9 in rat articular chondrocytes.

STUDY DESIGN

Experimental study.

PLACE AND DURATION OF STUDY

Jumma Research Laboratory and Histology Laboratory, The Aga Khan University, Karachi, from 2009 to 2011.

METHODOLOGY

Fresh slices of articular cartilage were taken from various synovial joints of rats of different age groups. The expression of AC isoforms was determined by RT-PCR and immunohistochemistry was performed to localise these isoforms in articular chondrocytes. Tissue sections were processed for immunostaining with respective antibodies. The color was developed by diaminobenzidine.

RESULTS

All the studied AC isoforms were found to be differentially expressed in different zones of the rat articular cartilage. Generally, expression of all AC isoforms studied increased with age. The expression of the AC isoforms through PCR was almost consistent with the localisation of these isoforms by immunohistochemistry.

CONCLUSION

These data add to the information about signalling cascades possibly involved in articular chondrocytes. Variable expression of AC isoforms 2, 4, 7, and 9 suggest a role for the signalling cascades regulated by the AC isoforms in articular chondrocytes.