Contrasting effects of treatment with omega-3 and omega-6 essential fatty acids on peripheral nerve function and capillarization in streptozotocin-diabetic rats.
Essential fatty acid metabolism is impaired by diabetes mellitus and this may be important in the aetiology of peripheral nerve dysfunction. The effects of gamma-linolenic acid (omega-6) and fish oil (omega-3) alone, and in combination, on nerve function and capillarization were examined in 2-month streptozotocin-diabetic rats. Diabetes resulted in approximately 15% and 23% decreases in saphenous sensory and sciatic motor nerve conduction velocities, respectively (p < 0.001). Motor and sensory conduction velocities were in the non-diabetic range after both preventive and reversal omega-6 treatment of diabetic rats (p < 0.001). No significant changes occurred in omega-6 treated non-diabetic rats. Preventive omega-3 treatment was largely ineffective. Reversal treatment with a combination of omega-6 and omega-3 fatty acids was marginally effective and improved motor (p < 0.05), but not sensory conduction velocity. In vitro measurement of sciatic nerve resistance to hypoxic conduction failure in diabetic rats revealed a 56% increase in the time taken for the compound action potential amplitude to be reduced by 80% (p < 0.01) compared to non-diabetic rats. This was partially prevented by omega-6 treatment (29% increase, p < 0.01). Reversal omega-6 treatment had a lesser effect (37% increase, p < 0.05 compared to untreated diabetic rats). omega-3 treatment had no significant effect on conduction failure time. Sciatic endoneurial capillary density increased by 11% with preventive omega-6 treatment (p < 0.05), but was unaffected by reversal omega-6 and by omega-3 treatments.(ABSTRACT TRUNCATED AT 250 WORDS)
Dines
K C
KC
Department of Biomedical Sciences, University of Aberdeen, Scotland, UK.
Cotter
M A
MA
Cameron
N E
NE
D000818:Animals; D002196:Capillaries / Q000187:drug effects / Q000503:physiopathology*; D003921:Diabetes Mellitus, Experimental / Q000503:physiopathology*; D003929:Diabetic Neuropathies / Q000503:physiopathology*; D015525:Fatty Acids, Omega-3 / Q000494:pharmacology*; D005395:Fish Oils / Q000494:pharmacology*; D000860:Hypoxia; D008297:Male; D009046:Motor Neurons / Q000187:drug effects / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000503:physiopathology; D009431:Neural Conduction / Q000187:drug effects; D009475:Neurons, Afferent / Q000187:drug effects / Q000502:physiology; D010525:Peripheral Nerves / Q000187:drug effects / Q000503:physiopathology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012016:Reference Values; D012584:Sciatic Nerve / Q000098:blood supply / Q000187:drug effects / Q000503:physiopathology*; D013997:Time Factors; D017965:gamma-Linolenic Acid / Q000494:pharmacology*
D015525:Fatty Acids, Omega-3; D005395:Fish Oils; D017965:gamma-Linolenic Acid