Gosha-jinki-gan (herbal medicine) in streptozocin-induced diabetic neuropathy

Long-established systems of traditional medicine have evolved from systematic recordings of human experience over several millennia. Although not strictly based on concepts of modern science, they nevertheless are founded on a corpus of organised knowledge written in documents, and the evident conclusion is that the alleged "trial and error" methodology has provided useful drugs for humans. Herbal medicine should be investigated as a potential regimen for diabetic neuropathy for the following reasons: (1) diabetic neuropathy remains an important clinical problem affecting a significant proportion of diabetic subjects without satisfactory treatment; (2) there are multiple pathogenetic mechanisms in diabetic neuropathy; and (3) herbal medicine which is a combination prescription has unique synergistic and synthetic effects that result from interactions between individual herbal components, and may induce a wide range of therapeutic potential and utility. Gosha-jinki-gan (GJK), consisting of 10 herbs, has been widely used for a regimen of diabetic complications, including neuropathy, in Japan. However, the effect of GJK on experimental diabetic neuropathy has never been previously evaluated. We examined nerve conduction velocity (NCV) and nerve glucose, sorbitol, fructose and myo-inositol levels in streptozocin (STZ)-induced diabetic rats that were treated with GJK. After 1 week of the STZ injection in 7-9-week-old rats, GJK treatment (100 mg/100 g body weight/day) was started orally. At 16 weeks after the STZ injection, the sciatic NCV of GJK-treated diabetic rats improved significantly when compared to non-treated diabetic rats, although they were not yet normalised.(ABSTRACT TRUNCATED AT 250 WORDS)