1. ¹Departamento de Patología Experimental, Centro de Investigación y de Estudios Avanzados. Instituto Politécnico Nacional (CINVESTAV-IPN), México.
2. ²Centro de Investigación en Ciencias Biológicas, Universidad Autónoma de Tlaxcala, México.

Correspondence: Juan B. KOURI, Phn: (5255) 50613800 ext. 3343; Fax: (5255) 57479890 E-Mail: bkouri@mail.cinvestav.mx

^*Centro de Investigación y de Estudios Avanzados. IPN (CINVESTAV-IPN) Av. Instituto Politécnico Nacional No. 2508, Col. San Pedro Zacatenco, Apartado Postal 14740, C. P. 07360 México, D. F.

Received 3 November 2004; Revised 1 December 2004; Accepted 15 December 2004.

Abstract

The aim of this work was to study the ontogeny of chondrocyte cell division using embryo, adult and osteoarthritic (OA) cartilage. We searched for mitosis phases and performed a comparative evaluation of mitotic index, basic fibroblast growth factor b (FGFb), transforming growth factor 1 (TGF-1) receptors, cyclin dependent kinase (CDK1) and Cyclin-B expression in fetal, neonate, 3, 5, 8 weeks old rats and experimental OA. Our results showed that mitosis phases were observed in all normal cartilage studied, although, we found a decrease in mitotic index in relation to tissue development. No mitosis was detected in OA cartilage. We also found a statistical significant reduction in cell number in OA cartilage, compared with the normal tissue. Furthermore, FGFb and TGF-1 receptors diminished in relation to tissue development, and were very scarce in experimental OA. Western blot assays showed CDK-1 expression in all cases, including human-OA cartilage. Similar results were observed for Cyclin-B, except for 8 weeks, when it was not expressed. Our results suggest that cell division seems to be scarce, if not absent within the OA cartilage studied. Nevertheless, the existence of factors essential for cell division leaves open the question concerning chondrocyte proliferation in OA cartilage, which is likely to be present in the early stages of the disease.