The neurotoxicity of epidural hyaluronic acid in rabbits: a light and electron microscopic examination.
Because hyaluronic acid (HA) has an antiinflammatory effect and prevents and/or reduces tissue adhesion, we believed it possible that epidurally-administered HA during epidural adhesiolysis procedures could alleviate pain in patients with chronic lower back pain. Therefore, we performed this pre-clinical trial evaluation of epidurally-administered HA neurotoxicity by light microscopy (LM) and electron microscopy (EM) in rabbits. Twenty rabbits were randomly divided into two groups, a normal saline (NS) group (n = 10) and a HA group (n = 10). Saline (0.2 mL/kg of 0.9% solution) and the same volume of HA were injected into the epidural space. No rabbits showed any sensory-motor or behavior change during the 3-wk period, except for one rabbit in the NS group that showed decreased appetite, activity, and weight loss. By LM, two rabbits in the NS group showed abnormal findings considered to be the result of trauma and infection associated with epidural catheterization. EM findings showed no significant neurotoxic findings in either group. In conclusion, epidurally-administered HA did not cause neurotoxicity in rabbits.


CONCLUSIONS
We performed a pre-clinical trial evaluation on the neurotoxicity of hyaluronic acid administered epidurally by light microscopy and electron microscopy in rabbits. Epidurally-administered hyaluronic acid did not produce any sign of neurotoxicity in rabbits.
Lim
Young-Jin
YJ
*Department of Anesthesiology and Pain Medicine, Seoul National University, the †Department of Anesthesiology and Pain Medicine, SungKyunKwan University, and the ‡Department of Diagnostic Pathology, Samsung Medical Center, SungKyunKwan University School of Medicine, Seoul, Korea.
Sim
Woo-Seok
WS
Kim
Yong-Chul
YC
Lee
Sang-Chul
SC
Choi
Yoon-La
YL
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D006820:Hyaluronic Acid / Q000008:administration & dosage / Q000633:toxicity*; D007268:Injections, Epidural; D008297:Male; D008854:Microscopy, Electron; D009068:Movement / Q000187:drug effects; D009422:Nervous System Diseases / Q000139:chemically induced* / Q000473:pathology; D009457:Neuroglia / Q000473:pathology / Q000648:ultrastructure; D009474:Neurons / Q000473:pathology / Q000648:ultrastructure; D017288:Pain Threshold / Q000187:drug effects; D011817:Rabbits; D013116:Spinal Cord / Q000473:pathology / Q000648:ultrastructure
D006820:Hyaluronic Acid