Spatial-temporal expression of N-myc downstream-regulated gene 2 in mouse brain after traumatic brain injury

Objective To explore the spatial-temporal expression of N-myc downstream-regulated gene 2 (NDRG2) in mouse brain after traumatic brain injury (TBI). Methods Male mice were randomly divided into the following groups: sham, TBI 6 h, TBI 12 h, TBI 24 h, TBI 48 h, TBI 72 h, TBI 7 d. A modified weight-drop method was utilized to induce mice TBI model. Western blot was used to detect the NDRG2 protein levels. Immunofluorescence was used to explore the cellular and subcellular locations of NDRG2. Student t test was used for difference comparison of NDRG2 protein levels between TBI and sham mice. Results The results of western blot showed that theNDRG2 protein levels increased significantly from 12 hours after TBI (1.52 fold, t=3.181, P<0.05), peaked at 24 hours (1.92 fold, t=5.032, P<0.01). The results of immunofluorescence showed that NDRG2 signals were specifically located in astrocytes. Besides, we observed NDRG2 nuclear translocation and co-localization with terminal deoxynucleotidyl transferase dUTPnick end labeling (TUNEL) signal safter TBI. Conclusion NDRG2 protein levels significantly increased after TBI. Besides, the increased proteins were partly translocated into nucleus and were co-localized with TUNEL signals, indicating that NDRG2 was involved with apoptosis after TBI. Key words: N-myc downstream-regulated gene 2; Traumatic brain injury; Spatial-temporal expression