Patients with diabetes are commonly ocmplicated by peripheral neuropathy, which might have clinical implications for the use of regional block with local anesthetics. Streptozotocin (STZ) produces pancreatic β cell necrosis in the rat resulting
in
diabetes mellitus.
Of forth-five Sprague-Dawley rats, weighing 250-300gm, diabetes was induced in 30 rats by the injection of STZ (Sigma, St Louis, Mo) 60mg/Kg intraperitoneally in 0.01 M citrate buffer at pH 5.5 after an overnight fast.
All rats were anesthetized for nerve exposure with an intraperitoneal injection of pentobarbital (50mg/kg). all both sciatic nerves were exposed by incision of buttock with prone position. 0.1 milliliter of either 2% lidocaine or 0.5% bupivacaine
was
extrfascicularly injected with 25 gauze needle. Then we evaluated to the effects of local anesthetics on verve conduction and verve fiber injury in STZ induced diabetic rats by electrophysiologic and histopathologic finding.
@ES The result were as follows:
@EN 1. 2% lidocaine and 0.5% bupivacaine exhibited a similar potency and time course in three groups, control, diabetic, and Neutral protamine Hagedorn (NPH) treated diabetic groups.
2. The latency of compound muscle action potentials was significantly prolonged in diabetic group compared with control and NPH treated diabetic group.
3. Motor nerve conduction velocity (m/sec) was significantly decreased in diabetic group compared with control and NPH treated diabetic group.
4. The morphologic changes of nerve idduced by local anesthetics in normal rats were interstital edema and vacuolar changes of axonal cytoplasm.
5. The morphologic changes of verve induced by local anesthetics in diabetic rats were marked interstitial edema and severe degenerative changes of nerve fibers.
6. The morphologic changes of nerve induced by local anesthetics in NPH treated diabetic rats were mild intestinal edema.
So We suggest that early control of hyperglycemia in diabetes would reduce eletrophysiologic changes and injury of nerve fiber when needed regional anesthesia using local anesthetics.
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