Gene expression in meningeal lymphatic endothelial cells following traumatic brain injury in mice.

Meningeal lymphatic vessels transport both the cerebrospinal fluid and interstitial fluid to the deep cervical lymph nodes. Traumatic brain injury (TBI) is accompanied by meningeal injury. We hypothesized that the TBI-induced meningeal injury would damage lymphatic vessels and affect brain function. We observed altered gene expression in meningeal lymphatic endothelial cells (LECs) in a mouse model of TBI. Through flow cytometry-based cell sorting, meningeal LECs were obtained from a mouse model of controlled cortical impact 3 days after TBI. Microarray analysis, real-time polymerase chain reaction assays, and enzyme-linked immunosorbent assays were performed to determine mRNA and protein expression levels in meningeal LECs. The number of meningeal LECs was significantly lower in the injury group than in the sham group 3 days after TBI. Additionally, the mRNA expression of lymphatic vessel endothelial hyaluronan receptor 1 (a specific marker of lymphatic vessels) in meningeal LECs was significantly lower in the injury group than in the sham group. The mRNA and protein expression of FMS-like tyrosine kinase 4 and neuropilin 2 (markers of lymphangiogenesis) in meningeal LECs was significantly higher in the injury group than in the sham group. Our findings indicate that TBI is associated with the impairment of meningeal LECs and meningeal lymphangiogenesis, which implicates lymphatic vessel injury in the pathogenesis of this condition.

Effects of Preexisting Diabetes Mellitus on the Severity of Traumatic Brain Injury.

Falls and traffic accidents can cause traumatic brain injury (TBI). Assessment of the injury severity is essential to determine the prognosis or the cause of death. Diabetes mellitus (DM) is a common preexisting disease in elderly adults. We hypothesized that preexisting DM exacerbates TBI secondary to prolonged inflammation. In this study, we investigated TBI-induced changes in nerve function and inflammatory cell migration to the injury site, and the extent of brain contusion in KK-Ay (DM) and C57BL/6J (non-DM) mice. A controlled cortical impact device was used to induce TBI in each mouse. The brain contusion volume was measured using magnetic resonance imaging. Nerve function changes were assessed using the following animal behavior tasks: neurological severity score (NSS), Morris water maze, forced swim test, and beam walking. Immunohistochemical examinations of brain sections were performed to assess the infiltration of neutrophils, astrocytes, microglia, and macrophages, and to detect apoptosis. These experiments were performed on post-injury days 1-90 (over five experiments/time-points in each group). Compared with non-DM mice, DM mice showed significantly greater brain contusion volume, greater deterioration in the NSS, and a higher number of neutrophils, macrophages, and apoptotic cells in the brain tissue specimens. This study indicates that the prognosis of normal mice and DM mice differs, even if they acquire a TBI of the same severity. Therefore, it is important to evaluate patients with TBI for DM and other preexisting diseases in order to provide adequate treatment or to determine the correct cause of death.

Detection of cocaine and metabolites from mouse femur buried in soil.

Drug addicts are frequently involved in committing homicides, and burial in the ground is often performed by offenders for body disposal. Therefore, toxicological analyses of buried bones are vitally important for investigating the cause and circumstance of death. Cocaine concentrations in heart blood, femoral muscle, and femur were measured in mice after injections of 5, 15, and 30 mg/kg cocaine and in femurs buried in soil. The concentrations of cocaine in femurs (253.67-1345.31 ng/g) were higher than those found in heart blood (3.14-28.73 ng/mL) and femoral muscle (76.41-429.76 ng/g). The cocaine concentrations in buried femurs (54.83-388.68 ng/g) were significantly lower than those in unburied femurs (253.67-1345.31 ng/g). Further, cocaine was detected in femurs after being buried for 7-180 days in soil. These findings indicate that cocaine concentrations are higher in bone than in heart blood and femoral muscle and that the concentration decreases after burial in soil.

Quantification of Methamphetamine in Mouse Thighbones Buried in Soil.

Bone samples are used for analysis of drugs in decomposed or skeletonized bodies. Toxicological analyses of buried bones are important for determining the causes and circumstances of death. In this study, methamphetamine and amphetamine concentrations in heart blood, thigh muscles, and thighbones were analyzed using solid-phase extraction with liquid chromatography-tandem mass spectrometry. Methamphetamine concentrations in heart blood, thigh muscle, and thighbone ranged from 0.041 to 0.873 µg/mL, 0.649 to 2.623 µg/g, and 56.543 to 643.371 µg/g, respectively. Thighbone concentrations were significantly higher than those in heart blood or thigh muscles were. Methamphetamine concentrations in buried thighbone (4.010-45.785 µg/g) were significantly lower than those of unburied thighbones were (56.543-643.371 µg/g). Methamphetamine and amphetamine were detected in thighbones buried for 7-180 days. These findings indicate that the methamphetamine concentrations in bone are higher and decrease after burial in soil.