Effects of long-chain fatty alcohol on peripheral nerve conduction and bladder function in diabetic rats

Diabetic cystopathy as manifested by an enlarged bladder is mainly caused by peripheral neuropathy. Long-chain fatty alcohol, which has been isolated from the Far-Eastern traditional medicinal plant, Hygrophilia erecta, Hochr., has been found to possess some neurotrophic activities on the central neuron. Cyclohexenonic long-chain fatty alcohol (FA) used in this study were synthesized in order to improve the efficiency of the molecules. The effects of this compound on peripheral nerves, however, have not yet been studied. To get more information, we evaluated the effects of this compound on peripheral nerves in streptozotocin-induced diabetic rats in terms of nerve conduction velocity and bladder function. Three experiments were performed 8 weeks after the administration of streptozotocin to 8-week-old rats: (i) motor sciatic nerve conduction (MNCV), (ii) monitoring micturition behavior in the metabolic cage, and (iii) cystometrogram under urethane anesthesia (CMG). Half of the diabetic rats were treated with FA (8 mg/kg/day, i.p.). The difference in MNCV between control rats (49.0 +/- 2.2 m/s) and untreated diabetic rats (42.4 +/- 0.5 m/s) after 8 weeks reached significance (p = 0.0183). FA-administrated diabetic rats showed an improved MNCV (45.8 +/- 1.2 m/s). We also identified a significant improvement of bladder function in these animals. The diabetic rats had a much higher maximal micturition volume per 24 hours (4.9 +/- 0.4 ml) than control animals (1.5 +/- 0.1 ml). However, the diabetic rats treated with FA had a maximal micturition volume of only 3.7 +/- 0.3 ml. Likewise, the diabetic rats had a CMG bladder capacity of 0.90 +/- 0.14 ml while the diabetic rats treated with FA had a capacity of 0.54 +/- 0.07 ml. These results indicate that cyclohexenonic long-chain fatty alcohol has a beneficial effect on peripheral neuropathy and cystopathy in streptozotocin-induced diabetic rats.