Cervical central canal occlusion induces noncommunicating syringomyelia.
BACKGROUND
Mechanisms underlying the development of noncommunicating syringomyelia are poorly understood.


OBJECTIVE
To assess the influence of focal arachnoiditis and central canal (CC) occlusion (CCO) on the formation of noncommunicating syringomyelia in the adult rat cervical spinal cord. Expression of pericanalicular aquaporin-4 is also examined.


METHODS
Sprague-Dawley rats were subjected to circumferential or dorsal arachnoiditis (n = 34). Rats undergoing CCO (n = 69) were divided into 4 groups: group A, kaolin injection at a single site in the dorsal columns near the CC; group B, kaolin injection at multiple sites in the dorsal columns near the CC; group C, saline injection at multiple sites in the dorsal columns near the CC; or group D, controls. Rats were killed at 1, 4, 8, and 12 weeks. The CC area and aquaporin-4 (AQP4) expression were measured at the level of maximal CC enlargement.


RESULTS
Circumferential and dorsal arachnoiditis induced a mild increase in the CC area at 12 weeks. Single-site CCO induced slight CC enlargement. In contrast, multiple sites of CCO in proximity frequently induced a major expansion of the CC area (up to 50 times). Increased AQP4 expression was observed in pericanalicular astrocytes proportional to the degree of CC expansion.


CONCLUSIONS
Multiple sites of CCO created a model of noncommunicating syringomyelia in adult rats. Increased astrocytic AQP4 expression was proportional to the degree of CC expansion. Modulation of aquaporin expression may be a novel target for therapeutic interventions to prevent syringomyelia.
Kentucky Spinal Cord Injury Research Center and Department of Neurological Surgery, University of Louisville, Louisville, KY, USA.
Yongjie
Y
Zhang
Yi Ping
YP
Zhang
Lisa B E
LB
Shields
Yiyan
Y
Zheng
Xiao-Ming
XM
Xu
Scott R
SR
Whittemore
Christopher B
CB
Shields
D000818:Animals; D051401:Aquaporin 4 / Q000378:metabolism; D001100:Arachnoiditis / Q000139:chemically induced / Q000150:complications; D002574:Cervical Vertebrae; D004195:Disease Models, Animal; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D007616:Kaolin / Q000633:toxicity; D007796:Laminectomy; D051381:Rats; D017207:Rats, Sprague-Dawley; D013115:Spinal Canal / Q000473:pathology*; D013130:Spinal Stenosis / Q000139:chemically induced / Q000150:complications*; D013595:Syringomyelia / Q000209:etiology*; D013997:Time Factors
D051401:Aquaporin 4; D007616:Kaolin