RESUMO
OBJECTIVE: To observe the effect of Tongmai Jiangtang Capsule (TJC) on experimental diabetic peripheral neuropathy (DPN) rats. METHODS: Forty Wistar rats were divided into the TJC group, the mecobalamin treatment group, the model group, and the normal group according to random digit table, 10 in each group. Except rats in the normal group, DPN rat model was prepared using intraperitoneally in- jecting streptozotocin (STZ) in the rest rats. One rat in the model group died during the modeling. Different drugs were administered by gastrogavage to rats in corresponding groups from the 8th week after successful modeling. TJC (0.23 g crude drugs/mL, 10 mL/kg) was administered to rats in the TJC group by gastrogavage. Suspension of mecobalamin and normal saline (10 mL/kg, 0.05 mg/mL) was administered by gastrogavage to rats in the mecobalamin treatment group to the end of the 12th week. Meanwhile, equal volume of distilled water was administered by gastrogavage to rats in the model group and the normal group. Peripheral nerve conduction velocity was detected in each group. Gait analysis was performed. Changes of intraepidermal nerve fiber were observed by immunohistochemical assay. Pathological changes of tibial nerve tissue were observed using HE staining. RESULTS: (1) Compared with the normal group, the nerve conduction velocity was slowed down; print length (PL), intermediary toe spread (ITS), and toe spread (TS) were added in the model group, with statistical difference (P <0. 01). Compared with the mod- el group, nerve conduction velocity was speeded; PL and ITS decreased in the TJC group and the mecobal- amin treatment group, with statistical difference (P <0. 01). Besides, the nerve conduction velocity was superior in the TJC group than in the mecobalamin treatment group, with statistical difference (P <0. 05). (2) Immunohistochemical results showed, the staining of intraepidermal nerve fiber was not clear and dispersedly distributed in the model group, with no nerve fiber staining in local regions. Nerve fibers were not regular in lesser amount and shallow stained in the mecobalamin treatment group, with no nerve fiber staining in local regions. Nerve fibers were not regular in lesser amount and dispersedly distributed in the TJC group. (3) HE staining showed that tibial nerve tissue was severely swollen with swollen myelin sheath in the mod- el group. It was difficult to identity myelin sheath. Vaculole degenerated in local regions. Swollen axon could be seen. Partial axons were separated and degenerated. In the mecobalamin treatment group tibial nerve tissue was edematous with swollen myelin sheath. It was difficult to identity myelin sheath. Axons were locally separated. In the JMC group tibial nerve tissue was swollen with unclear myelin sheath and swollen axons. CONCLUSION: TJC could improve peripheral neuropathy of diabetic rats.
