Carbon nanotubes impregnated with subventricular zone neural progenitor cells promotes recovery from stroke

Abstract

Sung Ung Moon,1,* Jihee Kim,1,2,* Kiran Kumar Bokara,1,* Jong Youl Kim,1 Dongwoo Khang,3,4 Thomas J Webster,3,4 Jong Eun Lee1,21Department of Anatomy, 2Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul, South Korea; 3School of Engineering, 4Department of Orthopedics, Brown University, Providence, RI, USA*These authors contributed equally to this workAbstract: The present in vivo study was conducted to evaluate whether hydrophilic (HL) or hydrophobic (HP) carbon nanotubes (CNTs) impregnated with subventricular zone neural progenitor cells (SVZ NPCs) could repair damaged neural tissue following stroke. For this purpose, stroke damaged rats were transplanted with HL CNT-SVZ NPCs, HP CNT-SVZ NPCs, or SVZ NPCs alone for 1, 3, 5, and 8 weeks. Results showed that the HP CNT-SVZ NPC transplants improved rat behavior and reduced infarct cyst volume and infarct cyst area compared with the experimental control and the HL CNT-SVZ NPC and SVZ NPCs alone groups. The transplantation groups showed an increase in the expression of nestin (cell stemness marker) and proliferation which was evident with the increased number of doublecortin and bromodeoxyuridine double-stained immunopositive cells around the lesion site. But, these effects were more prominent in the HP CNT-SVZ NPC group compared with the other transplantation groups. The HP CNT-SVZ NPC and HL CNT-SVZ NPC transplants increased the number of microtubule-associated protein 2 (marker for neurons) and decreased the number of glial fibrillary acidic protein (marker for astroglial cells) positive cells within the injury epicenter. The majority of the transplanted HP CNT-SVZ NPCs collectively broadened around the ischemic injured region and the SVZ NPCs differentiated into mature neurons, attained the synapse morphology (TUJ1, synaptophysin), and decreased microglial activation (CD11b/c [OX-42]). For these reasons, this study provided the first evidence that CNTs can improve stem cell differentiation to heal stroke damage and, thus, deserve further attention.Keywords: biocompatibility, brain, in vivo, stem cell, wettability, carbon nanotubes, stroke