Modifications of Golgi Complex in Chondrocytes from Osteoarthrotic (OA) Rat Cartilage

Abstract

S U M M A R YThe status of the Golgi complex in normal vs osteoarthrotic (OA) cartilage has not yet been studied. A monoclonal antibody, MAb 58-K-9, allowed scoring of Golgi labeling intensity. In addition, ultrastructural assessment enabled us to focus on the distribution and relation between the endoplasmic reticulum (ER) and Golgi membranes. The study was performed in both normal and partially menisectomized OA-induced rat cartilage 20 and 45 days after surgery. Comparing Golgi immunolabeling intensities (mean Ϯ SEM) revealed a highly significant difference between normal (9.98 Ϯ 1.25), 20-day (2.49 Ϯ 0.34), and 45-day (0.82 Ϯ 0.22) cartilage. Moreover, chondrocytes from normal cartilage displayed 71.18% of labeling intensity in contrast to OA cartilage, in which chondrocyte labeling intensities were 24.95% (20 days) and 8.11% (45 days). OA chondrocytes appeared to display an overall reduction in Golgi labeling intensity, suggesting disruption of this organelle as the OA damage progressed. Interestingly, many 20-day OA-induced chondrocytes exhibited bubble-like Golgi immunolabeling compartmentalizing the cytoplasm, concomitant with putative apoptotic nuclear changes. At the same time, OA chondrocytes with a typical ultrastructural apoptotic pattern revealed a prominent ER gathered together with Golgi vesicles and saccules, also appearing to compartmentalize chondrocyte cytoplasm. We speculate about the role of Golgi modifications and apoptosis in OA pathogenesis.

Cell death of chondrocytes is a combination between apoptosis and autophagy during the pathogenesis of Osteoarthritis within an experimental model

“…Cartilages of all joints were obtained from the weight bearing areas of the condyles (the experimental procedures followed the National Research Guidelines). All samples were immediately fixed in 4% PBS-paraformaldehyde during 2 h at room temperature [29].…”

“…However, Microtubule-associated proteins-light chain-3 (MAP-LC3, LC3) is a major constituent of the autophagosomes and remains on the membrane even after spherical autophagosomes are completely formed; the cytoplasmic form LC3I (18 kDa), is processed and recruited to the autophagosomes, where LC3II (16 kDa) is generated by site specific proteolysis and lipidation near to the C-terminus [27]. Therefore, LC3II is considered as a specific autophagy marker [29].…”

Ontogeny of rat chondrocyte proliferation: studies in embryo, adult and osteoarthritic (OA) cartilage

“…Pre-incubation was performed with 0.2% IgG-free bovine serum albumin (Sigma Chemical Co., St Luis, MO) for 20 min at room temperature. Overnight incubation at 4°C with primary antibodies was followed by FITC-tagged anti-mouse and FITC-tagged antirabbit, respectively (6 µg/ml in PBS, Santa Cruz Biotechnology; Santa Cruz, California), for 1 h at room temperature [26,27]. Negative control was achieved by excluding the corresponding primary antibodies from the reaction and Vero cells, which are a fibroblastic cell line, were used as positive control.…”

Polymerized-Type I Collagen Induces a High Quality Cartilage Repair in a Rat Model of Osteoarthritis

“…During the second week, rats were grasped and OPEN ACCESS https://scidoc.org/IJBRR.php released from the total height of the box. This exercise stimulated the muscles, joints and bones by working flexion and extension and compression of the limbs [9,[22][23][24].…”

“…Cartilages of all joints were obtained from the weight bearing areas of the condyles. All samples were immediately fixed in 4% PBS-paraformaldehyde during 24 hours at room temperature [22][23][24]. Fixed samples were cryosectioned (Leica CM 1100; Heerbrugg, Switzerland) and mounted on gelatin coated slides.…”