Axonal transport of substance P-like immunoreactivity in ganglioside-treated diabetic rats

This study examined the effect of treatment of control and streptozotocin-diabetic rats with a mixture of gangliosides, derived from bovine brain, on parameters of axonal transport of substance P-like immunoreactivity (SPLI) and its levels in sciatic nerve and lumbar spinal ganglia. Rats were treated daily (10 mg/kg i.p.) for 28 days and compared with untreated control and diabetic groups. The duration of diabetes was 28 days in both cases. Untreated diabetic rats showed deficits in accumulation of axonally transported SPLI proximal (59% of controls) and distal (34% of controls) to sciatic nerve ligations (left in place for 12 h). Rates of accumulation were unaltered by diabetes. There were small numerical reductions in the SPLI content of unconstricted sciatic nerve and of L4 and L5 dorsal root ganglia in diabetic rats. None of these diabetes-associated changes was altered by ganglioside treatment, nor was there any indication of an effect of gangliosides on substance P in non-diabetic rats. The implications are discussed in relation to the possible pathogenesis of diabetic neuropathy.