tfc-612 and Diabetic-Neuropathies

A new prostaglandin E1 analogue, TFC-612, was given orally to 2 month-old spontaneously diabetic GK (Goto-Kakizaki) rats for 3 months to ascertain its effects on reduced motor nerve conduction velocity (MCV). A high dose of this compound (0.3 mg/kg body weight) significantly restored MCV after 2 and 3 months of administration, although the low dose (0.03 mg/kg body weight) did not. In addition, 1 month administration of TFC-612 significantly improved the reduced MCV in aged (5 month-old) GK rats only in the high dose group (0.3 mg/kg body weight), but not in the low dose group (0.03 mg/kg body weight). Although TFC-612 significantly suppressed sorbitol accumulation in the sciatic nerves of GK rats in a dose dependent manner after 3 months administration, this suppression was not observed after either 2 months administration to 2 month-old GK rats or after 1 month administration to 5 month-old GK rats. Fasting blood glucose levels of all GK rats remained high throughout the experiments, regardless of TFC-612 administration. TFC-612's improvement on reduced motor nerve conduction velocity was related partly to suppression of sorbitol accumulation, but other factors, including microcirculation, may contribute significantly to this effect. These results suggest that TFC-612 may be beneficial in the treatment of diabetic nerve impairment.

Topics: Aging; Alprostadil; Animals; Blood Glucose; Blood Pressure; Diabetes Mellitus, Experimental; Diabetic Neuropathies; Dose-Response Relationship, Drug; Male; Motor Neurons; Neural Conduction; Rats; Rats, Inbred Strains; Rats, Mutant Strains; Sciatic Nerve; Sorbitol

The effect of a newly developed oral agent, prostaglandin E1 (PGE1) analogue TFC 612, on diabetic neuropathy was studied by giving it for 6 wk to streptozocin-induced diabetic rats that had been diabetic for 3 mo and was compared with the effects of aldose reductase inhibitor ONO 2235. Although both compounds improved decreased motor nerve conduction velocity, the effect of TFC 612 continued during the 6 wk of treatment, whereas that of ONO 2235 became weaker from wk 4. The abnormality in sciatic nerve sorbitol and myo-inositol levels was reversed with ONO 2235, whereas it was unchanged with TFC 612. With the laser Doppler flowmetry technique, a decrease in the sciatic nerve blood flow in diabetic rats was shown to improve with both compounds, but TFC 612 had a greater effect than ONO 2235, and the increased lactate level of the diabetic nerve was corrected with both compounds, suggesting that both may be associated with the amelioration of ischemia in the diabetic endoneurium. Both TFC 612 and ONO 2235 partially but significantly normalized decreased fiber size in diabetic rats. On the other hand, TFC 612 completely normalized the dilated lumen area in diabetic rats, whereas ONO 2235 did not. These results suggest that the PGE1 analogue TFC 612 has a significant effect on diabetic neuropathy, possibly via vasotropic action, and may be a potent compound for the treatment of diabetic neuropathy.

Topics: Adenosine Triphosphate; Aldehyde Reductase; Alprostadil; Animals; Diabetes Mellitus, Experimental; Diabetic Neuropathies; Electrophysiology; Inositol; Lactates; Male; Myelin Sheath; Nerve Fibers; Phosphocreatine; Rats; Rats, Inbred Strains; Rhodanine; Sciatic Nerve; Sorbitol; Streptozocin; Sugar Alcohol Dehydrogenases; Thiazoles; Thiazolidines

A new prostaglandin E1 analogue (TFC-612) was orally given to streptozocin-diabetic rats for 4 weeks after the induction of diabetes and its effects on motor nerve conduction velocity were studied. The compound significantly prevented a decrease of the velocity but did not reverse abnormal sorbitol and myo-inositol contents of the sciatic nerve. The results suggest that TFC-612 has a potent effect on diabetic nerve dysfunction via other mechanism than the correction of sorbitol and myo-inositol metabolisms and could be a potential compound for therapy of diabetic polyneuropathy.

Topics: Alprostadil; Animals; Diabetes Mellitus, Experimental; Diabetic Neuropathies; Inositol; Insulin; Male; Motor Neurons; Neural Conduction; Prostaglandins E, Synthetic; Rats; Rats, Inbred Strains; Sciatic Nerve; Sorbitol