Ginkgo biloba extract and its diterpene ginkgolide constituents ameliorate the metabolic disturbances caused by recombinant tissue plasminogen activator in rat prefrontal cortex

Zhi Chen,1–3,* Shunjie Bai,1–4,* Qingchuan Hu,1–4,* Peng Shen,2,3,5,* Ting Wang,2–4,* Zihong Liang,2,3,5,6,* Wei Wang,1–3 Xunzhong Qi,2,3,5 Peng Xie1,2,4–6 1Department of Neurology, Yongchuan Hospital, Chongqing Medical University, Chongqing, China; 2Institute of Neuroscience and the Collaborative Innovation Center for Brain Science, Chongqing Medical University, Chongqing, China; 3Chongqing Key Laboratory of Neurobiology, Chongqing, China; 4Key Laboratory of Laboratory Medical Diagnostics of Education, Department of Laboratory Medicine, Chongqing Medical University, Chongqing, China; 5Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China; 6Department of Neurology, The Inner Mongolia Autonomous Region People’s Hospital, Hohhot, Inner Mongolia, China *These authors contributed equally to this work Introduction: Although recombinant tissue plasminogen activator (rtPA) is a widely used therapy in patients with acute ischemic stroke, rtPA-induced toxicity or its adverse effects have been reported in our previous studies. However, Ginkgo biloba extract (GBE) may provide neuroprotective effects against rtPA-induced toxicity. Thus, in the present study, we investigated whether a single administration of rtPA caused neurotoxicity in the prefrontal cortex (PFC) of rats and determined whether GBE or its diterpene ginkgolide (DG) constituents were neuroprotective against any rtPA-induced toxicity. Materials and methods: We randomly divided adult Sprague-Dawley rats into four groups that were intravenously administered saline, rtPA, rtPA+DG, or rtPA+GBE. The rats were sacrificed 24 hours later and the whole brain removed. A gas chromatography–mass spectrometry metabolomic approach was used to detect molecular changes in the PFC among the groups. Multivariate statistical and pathway analyses were used to determine the relevant metabolites as well as their functions and pathways. Results: We found 32 metabolites differentially altered in the four groups that were primarily involved in neurotransmitter, amino acid, energy, lipid, and nucleotide metabolism. Our results indicated that a single rtPA administration caused metabolic disturbances in the PFC. Both GBE and DG effectively ameliorated these rtPA-induced disturbances, although DG better controlled the rtPA-induced glutamate and aspartate excitotoxicity and the activation of NMDA receptor. Conclusion: Our results provide important novel mechanistic insights into the adverse effects of rtPA and offer directions for future exploration on the thrombolytic effects of rtPA combined with the administration of DG or GBE for the treatment of acute ischemic stroke in humans. Keywords: recombinant tissue plasminogen activator (rtPA), diterpene ginkgolides (DG), Ginkgo biloba extract (GBE), metabolomics, prefrontal cortex, excitotoxicit