OBJECTIVE: To determine in situ using TEM the balance of apoptosis and necrosis in the articular cartilage of patients with inflammatory (rheumatoid arthritis and seronegative spondyloarthritis) and degenerative (osteoarthritis) joint diseases and to establish possible correlation between the cell death rate and the matrix vesicles formation.
METHODS: Cartilage samples of the knee joint were obtained from patients with rheumatoid arthritis (RA, 18 cases), osteoarthritis (OA, 22 cases), Reiter's disease (RD, 9 cases), peripheral form of the ankylosing spondyloarthritis (AS, 6 cases) and psoriatic arthritis (PA, 6 cases) during arthroscopy or knee surgery. Normal samples taken from autopsy cases without a history of joint diseases were used as control. Samples were processed for TEM with subsequent semi-quantitative estimation of the cell death rate in the superficial, middle and deep zone of non-calcified articular cartilage, and computer-aided ultramorphometric evaluation of the matrix vesicles of different types.
RESULTS: Both apoptotic and necrotic cell death could be identified in the cartilage of patients with inflammatory joint diseases, including seronegative spondyloarthritides and degenerative arthropathies. Apoptosis dominated over necrosis in all examined arthritides, including RA patients in which necrosis of the chondrocyte was the most frequent among arthropathies, while the highest apoptotic cell death rate was discovered in OA in which it correlated with the volume and numeric density of the matrix vesicles. These data provide evidence that apoptosis may contribute to the cartilage breakdown not only in RA and OA but also in the seronegative spondyloarthritides, which had a significantly higher apoptotic rate than the normal cartilage.
The spinal nucleus of the accessory nerve (SNA) comprises the group of somata (perikarya) of motor neurons that supply the sternocleidomastoid and trapezius muscles. There are many conflicting views regarding the longitudinal extent and topography of the SNA, even in the same species, and these disagreements prompted the present investigation. Thirty Sprague-Dawley rats (15 males, 15 females) were used. The SNA was localized by retrograde axonal transport of horseradish peroxidase. Longitudinally, the SNA was found to be located in the caudal part (caudal 0.9-1.2 mm) of the medulla oblongata, the whole lengths of cervical spinal cord segments C1, C2, C3, C4, C5 and rostral fourth of C6. In the caudal part of the medulla oblongata, the SNA was represented by a group of perikarya of motor neurons lying immediately ventrolateral to the pyramidal fibres that were passing dorsolaterally after their decussation. In the spinal cord, the motor neuronal somata of the SNA were located in the dorsomedial and central columns at C1, in the dorsomedial, central and ventrolateral columns at C2 and in the ventrolateral column only at C3, C4, C5 and rostral quarter of C6. The perikarya of motor neurons supplying the sternocleidomastoid were located in the caudal part (caudal 0.9-1.2 mm) of the medulla oblongata ventrolateral to the pyramidal fibres that were passing dorsolaterally after their decussation. They were also located in the dorsomedial and central columns at C1, in the dorsomedial, central and ventrolateral columns at C2 and only in the ventrolateral column at the rostral three-quarters of C3. The perikarya of motor neurons supplying the trapezius muscle were located in the ventrolateral column only in the caudal three-quarters of C2, the whole lengths of C3, C4 and C5, and in the rostral quarter of C6.