MiR-29b protects dorsal root ganglia neurons from diabetic rat.

Accumulated evidences implicated that microRNAs may be involved in diabetic neuropathy. Here, we investigated miR-29's roles in primary isolated dorsal root ganglion (DRG) neurons from STZ-induced diabetic rats. First, miR-29b was found down-regulated after STZ-injection. Inhibitions were increased with time course. Down-regulation of miR-29b was associated with higher apoptosis rate and more serious axonal swelling. Meanwhile, axonogeneration genes were inhibited, whereas neurodegenerative genes were stimulated. Restoration of miR-29b by mimic experiment could reverse the above neuropathy. Furthermore, western blot analysis disclosed that miR-29b could abolish Smad3 activation. In conclusion, the present study identifies that miR-29b could protect DRG from diabetic rats. This protective effects suggested potential therapeutic application of miR-29b in diabetic neuropathy.