Berberine Protects Secondary Injury in Mice with Traumatic Brain Injury Through Anti-oxidative and Anti-inflammatory Modulation.

Traumatic brain injury (TBI) is one of the major causes of death and disability worldwide. Novel and effective therapy is needed to prevent the secondary spread of damage beyond the initial injury. The aim of this study was to investigate whether berberine has a neuroprotective effect on secondary injury post-TBI, and to explore its potential mechanism in this protection. The mice were randomly divided into Sham-saline, TBI-saline and TBI-Berberine (50 mg/kg). TBI was induced by Feeney's weight-drop technique. Saline or berberine was administered via oral gavage starting 1 h post-TBI and continuously for 21 days. Motor coordination, spatial learning and memory were assessed using beam-walking test and Morris water maze test, respectively. Brain sections were processed for lesion volume assessment, and expression of neuronal nuclei (NeuN), cyclooxygenase 2 (COX-2), inducible nitric oxide synthase (iNOS), 8-hydroxy-2-deoxyguanosine (8-OHdG), ionized calcium-binding adapter molecule 1 (Iba1) and glial fibrillary acidic protein (GFAP) were detected via immunohistochemistry and immunofluorescence. There were statistically significant improvement in motor coordination, spatial learning and memory in the TBI-Berberine group, compared to the TBI-saline group. Treatment with berberine significantly reduced cortical lesion volume, neuronal loss, COX-2, iNOS and 8-OHdG expression in both the cortical lesion border zone (LBZ) and ipsilateral hippocampal CA1 region (CA1), compared to TBI-saline. Berberine treatment also significantly decreased Iba1- and GFAP-positive cell number in both the cortical LBZ and ipsilateral CA1, relative to saline controls. These results indicated that berberine exerted neuroprotective effects on secondary injury in mice with TBI probably through anti-oxidative and anti-inflammatory properties.

Dopaminergic neurons show increased low-molecular-mass protein 7 activity induced by 6-hydroxydopamine in vitro and in vivo.

BACKGROUND: Abnormal expression of major histocompatibility complex class I (MHC-I) is increased in dopaminergic (DA) neurons in the substantia nigra (SN) in Parkinson's disease (PD). Low-molecular-mass protein 7 (ß5i) is a proteolytic subunit of the immunoproteasome that regulates protein degradation and the MHC pathway in immune cells. METHODS: In this study, we investigated the role of ß5i in DA neurons using a 6-hydroxydopamine (6-OHDA) model in vitro and vivo. RESULTS: We showed that 6-OHDA upregulated ß5i expression in DA neurons in a concentration- and time-dependent manner. Inhibition and downregulation of ß5i induced the expression of glucose-regulated protein (Bip) and exacerbated 6-OHDA neurotoxicity in DA neurons. The inhibition of ß5i further promoted the activation of Caspase 3-related pathways induced by 6-OHDA. ß5i also activated transporter associated with antigen processing 1 (TAP1) and promoted MHC-I expression on DA neurons. CONCLUSION: Taken together, our data suggest that ß5i is activated in DA neurons under 6-OHDA treatment and may play a neuroprotective role in PD.