[Effects of lisinopril on diabetic peripheral neuropathy: experiment with rats]

To investigate the effects of lisinopril, an angiotensin-converting enzyme inhibitor, on diabetic peripheral neuropathy (DNP).

Twenty-five Wistar rats underwent intravenous injection of streptozocin to establish diabetes models and 10 rats were injected with sodium citrate solution as normal controls. The diabetic rats were randomly divided into 2 groups: lisinopril group treated with gastric perfusion of lisinopril daily for 8 weeks, and diabetic control group. The diabetic controls and normal controls were treated with gastric perfusion of water. Sciatic nerve electrode penetration method was used to measure the motor nerve conduction velocity (MNCV) and sensory nerve conduction velocity (SNCV). Light and heat pain measuring apparatus was used to measure the pain threshold. Then the sciatic nerves were isolated. Electron microscopy was used to observe the ultra-structure. The contents of superoxide dismutase (SOD) and malonyldialdehyde (MDA), and Na(+)K(+)-ATPase activity were detected by chemical colorimetry. Immunohistochemistry was used to detect the CD34 in the sciatic nerve. The capillary density of sciatic nerve was calculated.

The MNCV and SNCV levels of the lisinopril group were both lower than those of the 2 control groups (all P < 0.01). The potency of heat pain leg retraction response of the lisinopril group was significantly shorter than that pf the diabetic control group (P < 0.05). The pathological changes of the lisinopril group were milder than those of the other groups. The SOD level and the Na(+)K(+)-ATPase activity of the diabetic group were significantly lower than those of the normal control group, and the MDA of the diabetic group was significantly higher than those of the other 2 groups (all P < 0.05). And the SOD level and Na(+)K(+)-ATPase activity of the lisinopril group were significantly higher than those of the diabetic control group, and the MDA level of the lisinopril group was significantly lower than that of the diabetic control group. The capillary density of sciatic nerve of the diabetic control group was lower and the normal control group, and that of the lisinopril group was significantly higher than that of the diabetic control group (P < 0.01).

ACE inhibitors effectively prevent and treat DPN.