The effects of hypertonic dextrose injection on connective tissue and nerve conduction through the rabbit carpal tunnel.
OBJECTIVE
To investigate the effects of hypertonic dextrose injection on the subsynovial connective tissue (SSCT) in a rabbit model. We hypothesized that dextrose injection would induce proliferation of the SSCT, hinder median nerve conduction, and alter SSCT mechanical properties, similar to what is observed in patients with carpal tunnel syndrome (CTS).


METHODS
Randomized, controlled prospective study.


METHODS
Not applicable.


METHODS
New Zealand white rabbits (N=28) weighing 4.0 to 4.5kg.


METHODS
One forepaw was randomly injected with 0.1mL 10% dextrose solution. The contralateral paw was injected with a similar amount of 0.9% saline solution as a control. Animals were killed at 12 weeks after injection.


METHODS
Animals were evaluated by electrophysiology (EP), mechanical testing, and histology. EP was evaluated by distal motor latency and amplitude. Shear force was evaluated when the middle digit flexor digitorum superficialis tendon was pulled out from the carpal tunnel. The ultimate tensile load and the energy absorption were also measured. Tissue for histology was evaluated qualitatively.


RESULTS
EP demonstrated significant prolongation of distal motor latency. The energy absorption and stiffness were also significantly increased in the dextrose group. Histologically, the dextrose group showed thickening of the collagen bundles and vascular proliferation within the SSCT compared with the saline group.


CONCLUSIONS
These results are consistent with the findings in patients with CTS and suggest that hypertonic dextrose injection has the potential to create a novel animal model in which to study the evolution of CTS.
Yoshii
Yuichi
Y
Biomechanics Laboratory, Division of Orthopedic Research, Mayo Clinic, Rochester, MN 55905, USA.
Zhao
Chunfeng
C
Schmelzer
James D
JD
Low
Phillip A
PA
An
Kai-Nan
KN
Amadio
Peter C
PC
D000818:Animals; D002349:Carpal Tunnel Syndrome / Q000139:chemically induced* / Q000473:pathology / Q000503:physiopathology; D002350:Carpus, Animal / Q000294:innervation*; D003238:Connective Tissue / Q000473:pathology*; D004195:Disease Models, Animal; D005355:Fibrosis; D005950:Glucose Solution, Hypertonic; D008475:Median Nerve / Q000503:physiopathology*; D009431:Neural Conduction; D010865:Pilot Projects; D011817:Rabbits; D011897:Random Allocation
D005950:Glucose Solution, Hypertonic