**Supplementary Materials:** Supplementary materials can be found at http://www.mdpi.com/1422-0067/20/8/1965/s1.

**Author Contributions:** C.C.M. (licence in veterinary medicine) designed and organized the animal protocol, performed the body weight, glycemia, and paw withdrawal latency measurements and did the animal sacrifice. A.B. and D.D.B. prepared the primary DRG neuronal cultures, performed the qRT-PCR experiments and analyzed the qRT-PCR data. D.S. performed the immunofluorescence experiments. C.M.R. did the digital analysis of the confocal microscopy images. B.M.R. and M.R. captured the confocal microscopy images, performed the statistical analysis of the experimental data, planned the experiments and wrote the paper.

**Funding:** This work was supported by the Romanian Ministry of Research and Innovation by means of the research grants PN 09 37 03 01/(2009-2015), PN 19 06 02 03/2019, and 36 PFE/2018. We are grateful to Dr. Adriana Georgescu from the Institute of Cellular Biology and Pathology "N. Simionescu" for helping us establish the protocol of STZ administration in mice and for her advices regarding the monitoring of the diabetes status. We also acknowledge Iulia Ghidu and Florentina Ioni¸tă for their participation to some of the immunofluorescence or qRT-PCR experiments during their master training. We also acknowledge Marzia Di Chio from the Department of Public Health and Community Medicine, University of Verona, Italy for helping us with the settings of the confocal microscope and the supervision of the image capture.

**Conflicts of Interest:** The authors declare no conflict of interest.
