Circular RNAs (circRNAs) are involved in a variety of diseases. However, the roles of circRNAs in traumatic brain injury (TBI) remain unknown. In this study, circRNA microarray was used to profile the altered circRNAs in the rat hippocampus following TBI. A total of 192 circRNAs were observed to be differentially expressed (FC ≥1.5 and P <0.05) after TBI ,including 98 up-regulated and 94 down-regulated. Gene ontology (GO) and KEGG pathway analysis indicated that many mRNAs transcribed from the host genes of altered circRNAs were implicated in brain damage and neural regeneration. CircRNA/miRNA interaction was predicted using Arraystar’s home-made miRNA target prediction software based on TargetScan and miRanda. Thus, our studies have demonstrated altered circRNA expression pattern in the rat hippocampus after TBI, which may play important roles in post-TBI physiological and pathological processes. These findings may provide not only a new direction for studying the molecular mechanisms underlying TBI but also new possibility for the treatment of TBI by modulating circRNAs.

Rationale: The blood-brain barrier (BBB) prevents the effective delivery of therapeutic molecules to the central nervous system (CNS). A recently generated adeno-associated virus (AAV)-based vector, AAV-PHP.eB, has been found to penetrate the BBB more efficiently than other vectors including AAV-PHP.B. However, little is known about the mechanisms. In this study, we investigated how AAV-PHP.eB penetrates the BBB in mice.

Several transport vectors, including nanoparticles, have been reported to be used for the delivery of therapeutic medicines crossing the impermeable blood-brain barrier (BBB) to treat the diseases in the central nerve system (CNS), such as traumatic brain injury (TBI). Poly(n-butyl-2-cyanoacrylate) (PBCA) nanoparticles, made from biocompatible material, are regarded as a better potential delivery tool than others such as gold nanoparticles due to their degradability in vivo . However, little is known whether PBCA nanoparticles can be used to deliver neurotrophic factors into the brain to treat TBI. In this study, we first synthesized PBCA-carried β -nerve growth factor, a neurotrophic agent with a large molecular weight, and then intravenously injected the compound into TBI rats. We found that despite undergoing several synthesis steps and host circulation, β -NGF was able to be successfully delivered into the injured brain by PBCA nanoparticles, still maintain its neurotrophic activity for neurite outgrowth, and reduce the mortality of TBI rats. Our findings indicate that PBCA nanoparticles, with Tween 80, are an efficient delivery vector and a protective reservoir for large molecular therapeutic agents to treat TBI intravenously.