Bovine colostrum truncated insulin like growth factor-I ameliorates peripheral neuropathy in diabetic rats

Objective To study the effects of small dose of bovine colostrum truncated insulin like growth factor Ⅰ (Bc tIGF Ⅰ) and recombinant human insulin like growth factor Ⅰ (rhIGF Ⅰ) on peripheral neuropathy in streptozotocin (STZ) induced diabetic rats.Methods STZ induced diabetes mellitus (DM) rats were allocated to three groups. One group received no treatment, another group intraperitoneal injection with Bc tIGF Ⅰ, the third group with rhIGF Ⅰ. And there was also a normal control group. The duration of treatment was 11 weeks. Blood glucose was measured at various times after treatment. Electrophysiological measurements and morphologic analyses of sciatic nerve were performed. Several related serum hormones (insulin, C peptide and IGF Ⅰ) were also assayed. Results Motor nerve conduction velocity (MNCV) of sciatic nerve and H reflex in Bc tIGF Ⅰ treated group was significantly improved in contrast to that in DM group (P0.05). However, treatment with rhIGF Ⅰ brings no improvement (P0.05). The ultrastructural appearance showed that treatment with Bc tIGF Ⅰ could alleviate diabetic neuropathy, but it did not happen in rhIGF Ⅰ group. Blood glucose concentration was lowered by Bc tIGF Ⅰ but not rhIGF Ⅰ therapy. Neither Bc tIGF Ⅰ nor rhIGF Ⅰ therapy affected serum levels of insulin and C peptide (P0.05). Conclusion Bc tIGF Ⅰ but not rhIGF Ⅰ can improve diabetic peripheral neuropathy at a lower dosage.