Expression change of microRNA-124 and its correlation with axon regeneration after traumatic brain injury in mice / 中华创伤杂志

ABSTRACT

Objective To observe the expression changes of microRNA-124(miRNA-124) following traumatic brain injury (TBI) in mice and investigate the correlation of miRNA-124 with neural axon regeneration.Methods Ninety-one C57BL/6 mice were assigned into TBI group (n =63) and control group (n =28) according to the random number table.Mice in TBI group were subjected to controlled cortical impact and euthanized at 12 hours and 1,3,7,14,21,28 days postinjury for the collection of brain tissue in the trauma zone.Mice in control group underwent craniectomy only.Trauma zone observation was done using the HE staining.Expression of miRNA-124 was detected using the real-time PCR.Levels of Nrp-1,Gap-43 and Tau were detected using the Western blot and immunohistochemical staining.Results After injtury,study of mice behavior and HE staining indicated the establishment of experimental model was successful.Expression of miRNA-124 reached the peak at 3 days postinjury (3.80 ± 0.22),expression of Nrp-1 reached the peak at 7 days postinjury (2.006 ±0.179),expression of Tau reached the peak at 14 days postinjury (2.063 ±0.172),and expression of Gap-43 sustained high level since 12 hours after injury(1.355 ± 0.093) (P ＜ 0.05).Count of axon marker positive cells in TBI group was the lowest at 1 day postinjury due to the direct damage and edema,and then slowly recovered.There was no significant difference in the count of axon marker positive cells between the two groups at 14,21 and 28 days postinjury (P ＞ 0.05),but the morphology in TBI group changed obviously.Although the positive cells of axon marker decreased at 1 day postinjury,expressions of miRNA-124,Nrp-1,Tau and Gap-43 in TBI group were significantly increased compared to the detections in control group (P ＜ 0.05).Conclusion Increased expression of miRNA-124 in trauma zone may closely related to axon regeneration after TBI in mice.