[Expression of aquaporin 4 during development of experimential presyrinx state in rabbits].
OBJECTIVE
To investigate the expression of AQP4 during the development of presyrinx state of experimental syringomyelia in rabbits.


METHODS
The experimental syringomyelia models of rabbits were established by intra-cisternal injection of Kaolin. The expression of AQP4 AQP4mRNA and the water content of upper cervical spinal cord were measured with immunohistochemistry Western blot RT-PCR and dry-wet measurement on days 1,3,7,14, and 21 after operation, respectively.


RESULTS
Compared with animals of control group, the water content increased in those of Kaolin group from the 1st day (68.35%+/-0.70%), reached its peak on the 7th day (72.92%+/-0.86%), lasted to the 14th day (72.58%+/-0.55%), and then began to drop on the 21st day (70.03%+/-0.77%), while AQP-4 immunoreactive expression decreased on the 3rd day [integral optical density(IOD) 320.5+/-44.2], reached its minimum on the 7th day (IOD 258.7+/-26.5), lasted to the 14th day, and recovered partially on the 21st day approximately (IOD 321.5+/-46.1). RT-PCR found the decreasing of AQP4 mRNA coincided well with that of AQP4 immunoreactive expression in presyrinx state. The linear regression analysis indicated that expression of AQP4 and its mRNA in cervical cord had a negative correlation with the change of spinal water content (r=-0.769, P<0.01; r=-0.955, P<0.01).


CONCLUSIONS
Downregulation of AQP4 and its mRNA expression may involve in edema formation in the presyrinx state of rabbits.
Sun
Guo-zhu
GZ
Department of Neurosurgery, The 2nd Hospital of Hebei Medical University, Shijiazhuang 050000, China.
Zhang
Qing-jun
QJ
Wang
Hao
H
D000818:Animals; D051401:Aquaporin 4 / Q000096:biosynthesis* / Q000235:genetics; D015153:Blotting, Western; D015536:Down-Regulation; D007150:Immunohistochemistry; D007616:Kaolin; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D011817:Rabbits; D011897:Random Allocation; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013116:Spinal Cord / Q000378:metabolism; D013595:Syringomyelia / Q000139:chemically induced / Q000235:genetics / Q000378:metabolism*; D014867:Water / Q000378:metabolism
D051401:Aquaporin 4; D012333:RNA, Messenger; D014867:Water; D007616:Kaolin