Optimization of an Intranasal Route for the Delivery of Human Neural Stem Cells to Treat a Neonatal Hypoxic-Ischemic Brain Injury Rat Model

Abstract

Siliang Lu,1,2 Ke Li,1,2 Yinxiang Yang,2 Qian Wang,2 Yu Yu,1,2 Zhaoyan Wang,2 Zuo Luan1 1The First Clinical Medical College, Guangxi Medical University, Nanning, 530021, Guangxi, People’s Republic of China; 2Laboratory of Pediatrics, The Sixth Medical Center of PLA General Hospital, Beijing, 100048, People’s Republic of ChinaCorrespondence: Zhaoyan Wang, Laboratory of Pediatrics, The Sixth Medical Center of PLA General Hospital, Beijing, 100048, People’s Republic of China, Tel [phone], Email [email protected] Zuo Luan, The First Clinical Medical College, Guangxi Medical University, Nanning, Guangxi, 530021, People’s Republic of China, Tel [phone], Fax [phone], Email [email protected]: Stem cell administration via the intranasal route has shown promise as a new therapy for hypoxic-ischemic encephalopathy (HIE). In this study, we aimed to improve the intranasal delivery of stem cells to the brain.Methods: Human neural stem cells (hNSCs) were identified using immunofluorescence, morphological, and flow cytometry assays before transplantation, and cell migration capacity was examined using the transwell assay. Cerebral hypoxia-ischemia (HI) was induced in 7-day-old rats, followed by the intranasal transplantation of CM-Dil-labeled hNSCs. We examined various experimental conditions, including preconditioning hNSCs with hypoxia, catheter method, multiple low-dose transplantation, head position, cell appropriate concentration, and volume. Rats were sacrificed 1 or 3 days after the final intranasal administration, and parts of the nasal tissue and whole brain sections were analyzed under a fluorescence microscope.Results: The isolated hNSCs met the characteristics of neural stem cells. Hypoxia (5% O2, 24 h) enhanced the surface expression of CXC chemokine receptor 4 (CXCR4) (9.21 ± 1.9% ∼ 24.76 ± 2.24%, P < 0.01) on hNSCs and improved migration (toward stromal cell-derived factor 1 [SDF-1], 0.54 ± 0.11% ∼ 8.65 ± 1.76%, P < 0.001; toward fetal bovine serum, 8.36 ± 0.81% ∼ 21.74 ± 0.85%, P < 0.0001). Further improvement increased the number of surviving cell distribution with increased uniformity on the olfactory epithelium and allowed the cells to stay in the nasal cavity for at least 72 h, but they did not survive for longer than 48 h. Optimization of pre-transplantation conditions augmented the success rate of intranasally delivered cells to the brain (0– 41.6%). We also tentatively identified that hNSCs crossed the olfactory epithelium into the tissue space below the lamina propria, with cerebrospinal fluid entering the cribriform plate into the subarachnoid space, and then migrated toward injured areas along the brain blood vessels.Conclusion: This study offers some helpful advice and reference for addressing the problem of repeatability in the intranasal delivery of stem cells.Keywords: neural stem cell, intranasal, optimization, transplantation, hypoxic-ischemic brain injury

Keywords

• neural stem cell
• intranasal
• optimization
• transplantation
• hypoxic-ischemic brain injury.