Stereological Studies On The Structure Plasticity Of Spinal Dorsal Horn In Painful Diabetic Neuropathy Rats And The Effects Of Metformin On Them

Objective:To observe the changes of spinal dorsal horn structural plasticity in Painful diabetic neuropathy（PDN）rats and the effects of metformin on them.Methods:The models of type 2 diabetic rats were established by the combination of streptozotocin and High-fat diet,and the models of PDN were established by screening the rats with pain threshold allergy,and the models were randomly divided into 2 groups:model group（PDN group）and treatment group（Met group）.The normal control group（C group）was also set.The Met group wasintervened 4 weeks with metformin 200mg.kg^-1.d^-1.After 4 weeks,the spinal cord tissues were removed after perfusion fixation.The whole segments of spinal cord and the L5 segments of the spinal cord were obtained by isometric random sampling principle,and 3-5 slices in each tissue block were taken for staining to display the neurons,synaptic precursors,astrocyte（Astrocyte,AS）.The number of the particles in the dorsal horn of the whole segment of spinal cor-d and the L5 segment were estimated by the optical disector.Results:1.There were no significant differences in the number of synapses between the groups in the whole spinal dorsal horn.2.In the L5segment of the spinal cord,compared with group C,the number of synapses in PDN group increased,and there was no significant difference in the Met group.Compared with the PDN group,the number of synapses in the Met group was reduced,and the number of the Met group was no significant difference.Conclusion:Metformin alleviated hyperalgesia in PDN rats and may be related to the increased number of synapses in the L5 segment of the spinal cord.