Neurotrophin-3 receptor switching promotes neural functional recovery in rats after spinal cord injury
- VernacularTitle:神经营养因子3经受体切换促进大鼠脊髓损伤后神经功能的恢复
- Author:
Yan CONG
1
;
Jian YU
;
Zhide SUN
;
Dawei KANG
Author Information
- Keywords: neurotrophin-3; autophagy; oligodendrocyte; receptor switching; apoptosis; spinal cord injury
- From: Chinese Journal of Tissue Engineering Research 2025;29(11):2268-2276
- CountryChina
- Language:Chinese
- Abstract: BACKGROUND:Neurotrophins represent a novel therapeutic approach for spinal cord injury,showing promising clinical applicability.Autophagy modulation is one of the mechanisms by which neurotrophins exert their effects,yet the specific signaling pathways involved remain unclear. OBJECTIVE:To explore how neurotrophin-3(NT-3)modulates autophagy in oligodendrocytes via switching between P75NTR and TrkC receptors and promotes neurological function recovery after spinal cord injury,aiming to further clarify the specific molecular mechanisms involved. METHODS:Twenty-four Sprague-Dawley rats were randomly divided into three groups:sham operation,spinal cord injury,and NT-3 groups.The therapeutic effect of NT-3 on spinal cord injury in rats was evaluated using the Basso,Beattie,and Bresnahan locomotor rating scale.The expression levels of NT-3,Olig1,myelin basic protein,and the autophagy marker LC3B in rat spinal cord tissue were detected by western blot.In a cellular experiment,oligodendrocytes were cultured in vitro and divided into six groups:oxygen-glucose deprivation(OGD),OGD+NT-3,OGD+NT-3+P75NTR plasmid,OGD+NT-3+TrkC plasmid,OGD+3-methyladenine(an autophagy inhibitor),and OGD+rapamycin(an autophagy activator).Oligodendrocyte morphology was observed under a light microscope,cell apoptosis was assessed by TUNEL staining,and the expression of TrkC receptor,P75NTR,LC3B,and the phosphorylation status of the PI3K/AKT/mTOR and AMPK/mTOR signaling pathways were evaluated by western blot. RESULTS AND CONCLUSION:Animal experiments demonstrated that compared with the sham operation group,NT-3 expression significantly increased after spinal cord injury(P<0.05);exogenous NT-3 treatment accelerated neurological function recovery in rats post spinal cord injury(P<0.05)and increased the expression of Olig1 and myelin basic proteins(P<0.05).Cellular experiments revealed that 3 hours marked the early to middle/late phase transition.Compared with the OGD group,oligodendrocytes in the OGD+NT-3 group could maintain their morphology for a longer period of time,TrkC receptor expression was lower in the early phase and significantly upregulated in the middle/late phase(P<0.05),whereas P75NTR protein expression was upregulated in the early phase and downregulated in the middle/late phase(P<0.05),and autophagy levels showed an initial increase followed by a decrease(P<0.05).By comparing the morphology and TUNEL staining results of cells in the OGD+NT-3,OGD+rapamycin,and OGD+3-methyladenine groups,we found that either promoting or inhibiting autophagy alone had adverse effects on oligodendrocyte survival,whereas modulating autophagy in a manner similar to NT-3 could maximally maintain cell survival.NT-3 could promote autophagy in the early phase via the P75NTR/AMPK/mTOR signaling pathway and inhibit autophagy in the later phase through the TrkC/PI3K/AKT/mTOR signaling pathway.Based on these findings,it is concluded that NT-3 can bidirectionally regulate autophagy in oligodendrocytes through the switching of P75NTR/TrkC receptors,thereby maintaining cell survival and facilitating the recovery of neurological functions in rats after spinal cord injury.
