Kurzfassung

Endochondral ossification represent an interesting model to analyse not only the regulation of chondrocyte proliferation and differentiation but also the base of different pathophysiological conditions in cartilage [1,2]. The complex developmental processes in growth plate cartilage are orchestrated by a great variety of hormonal and paracrine factors. Even if the role of arachidonic acid metabolites in different animal models is well known [3] little is known about its role in human growth...Endochondral ossification represent an interesting model to analyse not only the regulation of chondrocyte proliferation and differentiation but also the base of different pathophysiological conditions in cartilage [1,2]. The complex developmental processes in growth plate cartilage are orchestrated by a great variety of hormonal and paracrine factors. Even if the role of arachidonic acid metabolites in different animal models is well known [3] little is known about its role in human growth plate cartilage. We analysed the expression of COX-1, COX-2, the prostaglandin EP-1, EP-2, EP-3 and EP-4.
Paraffin sections from the growth plate of 10 fetal femurs were analysed immunohistochemically for the expression of COX-1, COX-2, EP-1, EP-2, EP-3 and EP-4. First antibodies were incubated over night. After incubation of the second antibody the antigenexpression was visualized with help of the Nova Red Staining Kit.
No expression of COX-1 or EP-1 could be found in any zone of the growth plate. The chondrocytes of the hypertrophic zone showed a strong expression of COX-2 and EP-3 but only a weak expression of EP-2 and EP-4 accentuated in the hypertrophic zone. The spatial distribution of Cox-2, EP-2, EP-3 and EP-4 expression is depicted in fig 1.
According the data available in the literature, this is the first description of the expression of cyclooxygenase and prostaglandin receptors in human fetal growth plate cartilage. These findings underline the hypothesis of a developmental role of COX-2 and prostaglandin E2. The differential expression of the prostaglandin receptors indicates a functional role of PGE2 in endochondral ossification. However, the functional role of this molecule in the different zones of the human growth plate has to be cleared up in further in vitro studies. In this context especially the effects of EP-3 and EP-4 for chondrocyte proliferation and differentiation as well as for bone formation is of special interest since ligands for these receptors are available in pharmaceutical quality.» weiterlesen» einklappen