Distribution of Inducible Nitric Oxide Synthase, Interleukin-1.BETA., and Interleukin-1 Receptor in the Temporomandibular Joint of Normal Rats.

Abstract

Nitric oxide (NO) is generated from Larginine by NO synthase (NOS) and has multiple functions under both physiological and pathological conditions. One isoform of NOS, inducible NOS (iNOS) is expressed in the cells such as macrophages after induction with various cytokines or mechanical stress. In this study, we investigated the distribution of iNOS, interleukin-1, (IL-1,) and its receptor, the IL-1 receptor (IL-1R), in the synovial membrane of the temporomandibular joint (TMJ) of normal rats using immunolight and immunoelectron microscopy. By light microscopy, an immunopositive reaction for iNOS and IL-1, was found in the superficial cells of the synovial membrane of both the anterior and posterior portions of the articular disc. Immunoelectron microscopy revealed that iNOSimmunoreactive products were deposited in the cytoplasm and vesicles, and on the plasma membrane of type-A (macrophage-like) and B (fibroblast-like) cells of the superficial layer. IL-1R-positive products were found both on the plasma membrane and in the vesicles of type-A cells of the synovial lining, and were observed in macrophages in the sublining layer. These results reveal that iNOS and IL-1, localize to the synovial membrane of the rat TMJ under physiological conditions. Therefore, it is likely that autocrine/paracrine effects of IL-1, induce NO generation by iNOS via the IL-1R in type-A cells. It is considered that cytokine-induced NO may play an important role in the physiological maintenance, e.g. self-protection, by synovial lining cells of the synovial membrane in the TMJ.

Experimental Model of Zymosan‐Induced Arthritis in the Rat Temporomandibular Joint: Role of Nitric Oxide and Neutrophils

“…Immunoelectron microscopy has revealed that immunoreactive iNOS is found in both synoviocytes type A (macrophage-like) and B (fibroblast-like) [45]. NO may play an important role in the physiological maintenance of the TMJ.…”

“…Our results revealed that iNOS was present in the articular disc, the articular cartilage chondrocytes, and the synovial cells of the rat TMJ under physiological conditions. Immunoelectron microscopy has revealed that immunoreactive iNOS is found in both synoviocytes type A (macrophage-like) and B (fibroblast-like) [ 45 ]. NO may play an important role in the physiological maintenance of the TMJ.…”

Localization of the Endogenous Cysteine Proteinase Inhibitor, Cystatin C, and the Cysteine Proteinase, Cathepsin B, to the Junctional Epithelium in Rat Gingiva

“…Specimens were prepared for immunohistochemistry followed by light microscopy according to the methods described in our previous reports [21,48,49]. Briefly, gingival specimens were immersed overnight in 0.1 M PB containing 20% sucrose at 4°C.…”

“…Immunohistochemistry was based on the avidin-biotinperoxidase complex (ABC) method (ABC Kit; Vector Laboratories, Burlingame, CA, USA) as described previously [21,48,49]. Immunohistochemistry was carried out at room temperature (RT).…”

“…Specimens were prepared for immunocytochemistry followed by electron microscopy according to the methods described in our previous reports [21,49] 2) for 60 min at RT before being dehydrated in a graded series of ethanol, embedded in Quetol-653 resin (Nissin EM, Tokyo, Japan), and polymerized at 60°C for 24 hr. The sections were then cut into ultra-thin (90 nm-thick) slices with a Richert-Jung Ultracut E ultramicrotome.…”