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

Objective: To observe stereological studies the changes of spinal structure plasticity in painful diabetic neuropathy(PDN)rats and the effects of metformin on them.Methods: Healthy adult male SD rats were randomly divided into 3 groups: normal control group(C group),model group(PDN group)and metformin treatment group(Met group).In the PDN group and the Met group,the model of type 2 diabetic rats was established by using the combination of single intraperitoneal injection of small dose streptozotocin and high fat diet,and diabetic rats with hyperalgesia were selected as the PDN model.In the end,the C group,the PDN group and the Met group were 7 rats,6 rats and 7 rats.Metformin was administered to the Met group for 200mg/kg/d(10ml 0.9% normal saline configuration),and 0.9% normal saline was administered to the PDN group for the same amount.Both groups lasted four weeks.After intragastric administration,the whole spinal cord of each group of rats was collected after cardiac perfusion fixation.According to the principle of isometric random sampling,2 sets of samples of the whole spinal cord and L5 segments were respectively taken for staining.The number of myelinated nerve fibers of the spinal thalamus bundle and oligodendrocytes of the spinal dorsal horn in the whole spinal cord and L5 segments were calculated by the somatological counting frame.Results: 1.After the establishment of the PDN model,compared with group C,PWT of the PDN group and the Met group decreased.Compared with the PDN group,PWT was increased in the Met group.2.In the whole spinal cord,compared with group C,the number of myelinated nerve fibers and oligodendrocytes in the PDN group increased,the number of myelinated nerve fibers increased in the Met group,but there was no significant difference in the number of oligodendrocytes.Compared with group PDN,the number of myelinated nerve fibers and oligodendrocytes in the Met group were significantly reduced.3.In the L5 segment,compared with group C,the number of myelinated nerve fibers and oligodendrocytes in the PDN group increased,the number of myelinated nerve fibers increased in the Met group,but there was no significant difference in the number of oligodendrocytes.Compared with group PDN,the number of myelinated nerve fibers and oligodendrocytes in the Met group were reduced.Conclusion: To some extent,metformin can ease hyperalgesia in PDN rats,which may be related to the regulation of the number of myelinated nerve fibers in the thalamus bundle of spinal cord and the number of oligodendrocytes in the spinal dorsal horn.