peptide in the MSCs + RSV group were improved compared with the diabetic control group, yet remained lower compared with those of the normal control group. \*P\<0.05 vs. the diabetic control group; ^\$^P\<0.05 vs. the insulin group; ^\#^P\<0.05 vs. the RSV group; ^&^P\<0.05 vs. the MSCs group and the MSCs + RSV group; ^\^^P\<0.05 vs. the normal control group. MSCs, mesenchymal stem cells; RSV, resveratrol.](etm-17-05-3555-g00){#f1-etm-0-0-7383}

![Histological examination of the sciatic nerve with hematoxylin and eosin staining, at a magnification of ×40. (A) Normal control group; (B) diabetic control group, with the left arrow indicating that fibers were degenerated and misarranged with large cracks, and the right arrow indicating myelin vacuolization; (C) insulin group; (D) MSCs group; (E) RSV group; and (F) MSCs + RSV group. The blue arrow indicated a new capillary. MSCs, mesenchymal stem cells; RSV, resveratrol.](etm-17-05-3555-g01){#f2-etm-0-0-7383}

![Levels of NF-κB, NGF and MBP in the sciatic nerve, assessed by immunohistochemistry. The level of NF-κB in the diabetic control group was markedly increased, while levels of NGF and MBP were decreased compared with the normal control group). (A) Levels of NF-κB in the insulin, RSV, MSCs and MSCs + RSV group were notably decreased compared with diabetic control group, particularly in the RSV group and MSCs + RSV group. (B) Levels of NGF in the MSC group and MSCs + RSV group were higher compared with the insulin, RSV and diabetic control groups, yet were significantly decreased compared with the normal control group. (C) Levels of MBP in the MSCs group, RSV group and MSCs + RSV group were higher compared with the insulin and diabetic control groups. Levels of MBP in the insulin and diabetic control groups were decreased compared with the other four groups. ^\^^P\<0.05 vs. the normal control group; ^\$^P\<0.05 vs. the insulin group; ^\#^P\<0.05 vs. the RSV group; \*P\<0.05 vs. the diabetic control group; ^&^P\<0.05 vs. the MSCs group and the MSCs + RSV group.