Abstract: Objective To observe the impacts of blood glucose fluctuation on the sciatic nerve of diabetic rats and its possible mechanism. Methods Rats were randomly divided into control group (NS group), continuous high glucose group (DM group) and fluctuating blood glucose group (FDM group, Regular insulin and glucose were used to induce blood glucose fluctuation). After 12 weeks, the conduction velocity of sciatic nerve (MNCV) and HbA1C in rats were evaluated. HE staining was performed to observe the morphological changes of sciatic nerve. The expression of NGF, TrkA and p75 were determined by immunohistochemistry and Western blot. Results 1) Compared with the NS group, the HbA1C level of FDM group and DM group were increased (P<0.01); CV value of FDM group significantly higher than DM group and NS group (P<0.01) while with MNCV value was lower than DM group and NS group (P<0.05). 2) NGF and TrkA expression in FDM group was lower than that in DM group (P<0.05), while the expression of p75 was increased in DM group (P<0.05). Conclusions Blood glucose fluctuation may aggravate the progression of diabetic peripheral neuropathy at the same level of HbA1C, the mechanism of which may be related to the downregulation of NGF and TrkA expression, while the upregulation of p75 expression.

Key words: Diabetic peripheral neuropathy, Nerve growth factor, Receptor, trk A