Establishment of an Experimental Intracerebral Haemorrhage Model for Mass Effect Research using a Thermo-sensitive Hydrogel.

The mechanical response of brain tissue closely relates to cerebral blood flow and brain diseases. During intracerebral haemorrhage (ICH), a mass effect occurs during the initial bleeding and results in significant tissue deformation. However, fewer studies have focused on the brain damage mechanisms and treatment approaches associated with mass effects compared to the secondary brain injuries after ICH, which may be a result of the absence of acceptable animal models mimicking a mass effect. Thus, a thermo-sensitive poly (N-isopropylacrylamide) (PNIPAM) hydrogel was synthesized and injected into the rat brain to establish an ICH model for mass effect research. The PNIPAM hydrogel or autologous blood was injected to establish an ICH animal model, and the space-occupying volumes, brain tissue elasticity, brain oedema, neuronal cell death, iron deposition and behavioural recovery were evaluated. The lower critical solution temperature of PNIPAM hydrogel was 32 °C, and the PNIPAM hydrogel had a rough surface with similar topography and pore structure to a blood clot. Furthermore, the ICH model animals who received an injection of PNIPAM and blood produced similar lesion volumes, elasticity changes and mechanically activated ion channel piezo-2 upregulation in brain tissue. Meanwhile, slight iron deposition, neuronal cell death and brain oedema were observed in the PNIPAM hydrogel model compared to the blood model. In addition, the PNIPAM hydrogel showed good biocompatibility and stability in vivo via subcutaneous implantation. Our findings show that PNIPAM hydrogel cerebral infusion can form a mass effect similar to haematoma and minimize the interference of blood, and the establishment of a mass effect ICH model is beneficial for understanding the mechanism of primary brain injury and the role of mass effects in secondary brain damage after ICH.

Development of feather keratin nanoparticles and investigation of their hemostatic efficacy.

Chicken feathers are considered as the major waste in poultry industry, which are mostly constituted of keratin proteins. Development of feather keratin for biomedical application is very attractive for chicken feather recycling. Human hair keratins have been demonstrated the significant hemostatic efficacy in the previous studies, but there are few reports of feather keratin for the hemostatic application. Here, the chicken feather keratin nanoparticle was developed for use as a hemostatic agent. Keratin was extracted from chicken feather in the present study, and a modified ultrasonic dispersion method was used to prepare keratin nanoparticles. The characterizations of feather keratin extracts and nanoparticles were investigated, including electrophoretic separation, amino acid composition, particle size, zeta potential, morphology, chemical structure and crystal form. Additionally, the hemostatic efficacy in vitro and in vivo of keratin nanoparticles were also studied. The results of hemostatic tests showed that the bleeding time and blood loss in tail amputation and liver scratch rat models can be significantly decreased after application of feather keratin nanoparticles, which demonstrated the potential application of feather keratin nanoparticles for hemostasis.

An FMRI study of neuronal specificity in acupuncture: the multiacupoint siguan and its sham point.

Clarifying the intrinsic mechanisms of acupuncture's clinical effects has recently been gaining popularity. Here, we choose the Siguan acupoint (a combination of bilateral LI4 and Liv3) and its sham point to evaluate multiacupoint specificity. Thirty-one healthy volunteers were randomly divided into real acupoint (21 subjects) and sham acupoint (10 subjects) groups. Our study used a single block experimental design to avoid the influence of posteffects. Functional magnetic resonance imaging data were acquired during acupuncture stimulation. Results showed extensive increase in neuronal activities with Siguan acupuncture and significant differences between stimulation at real and sham points. Brain regions that were activated more by real acupuncture stimulation than by sham point acupuncture included somatosensory cortex (the superior parietal lobule and postcentral gyrus), limbic-paralimbic system (the calcarine gyrus, precuneus, cingulate cortex, and parahippocampal gyrus), visual-related cortex (the fusiform and occipital gyri), basal ganglia, and the cerebellum. In this way, our study suggests Siguan may elicit specific activities in human brain.