Neurophysiological basis for neurogenic-mediated articular cartilage anabolism alteration.
This study was designed to investigate the pathways involved in neurogenic-mediated articular cartilage damage triggered by a nonsystemic distant subcutaneous or intra-articular inflammation. The cartilage damage was assessed 24 h after subcutaneous or intra-articular complete Freund's adjuvant (CFA) injection measuring patellar proteoglycan (PG) synthesis (ex vivo [Na(2)(35)SO(4)] incorporation) in 96 Wistar rats. Unilateral subcutaneous or intra-articular injection of CFA induced significant decrease (25-29%) in PG synthesis in both patellae. Chronic administration of capsaicin (50 mg. kg(-1). day(-1) during 4 days), which blunted the normal response of C fiber stimulation, prevented the bilateral significant decrease in cartilage synthesis. Similarly, intrathecal injection of MK-801 (10 nmol/day during 5 days), which blocked the glutamatergic synaptic transmission at the dorsal horn of signal originating in primary afferent C fibers, eliminated the CFA-induced PG synthesis decrease in both patellae. Chemical sympathectomy, induced by guanethidine (12.5 mg. kg(-1). day(-1) during 6 wk), also prevented PG synthesis alteration. Finally, compression of the spinal cord at the T3-T5 level had a similar protective effect on the reduction of [Na(2)(35)SO(4)] incorporation. It is concluded that the signal that triggers articular cartilage synthesis damage induced by a distant local inflammation 1) is transmitted through the afferent C fibers, 2) makes glutamatergic synaptic connections with the preganglionic neurons of the sympathetic system, and 3) involves spinal and supraspinal pathways.
Gouze-Decaris
E
E
Laboratoire de Physiopathologie et Pharmacologie Articulaires, Unite Mixte Recherche 7561 Centre National de la Recherche Scientifique-Université Henri Poincaré-Nancy I, France.
Philippe
L
L
Minn
A
A
Haouzi
P
P
Gillet
P
P
Netter
P
P
Terlain
B
B
D000344:Afferent Pathways / Q000378:metabolism; D000818:Animals; D002211:Capsaicin / Q000494:pharmacology; D002358:Cartilage, Articular / Q000294:innervation* / Q000378:metabolism*; D016291:Dizocilpine Maleate / Q000494:pharmacology; D004734:Energy Metabolism / Q000502:physiology*; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D005620:Freund's Adjuvant; D008297:Male; D020078:Neurogenic Inflammation / Q000139:chemically induced / Q000378:metabolism*; D009619:Nociceptors / Q000378:metabolism; D011509:Proteoglycans / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013563:Sympathectomy, Chemical
D018691:Excitatory Amino Acid Antagonists; D011509:Proteoglycans; D016291:Dizocilpine Maleate; D005620:Freund's Adjuvant; D002211:Capsaicin