[The Role of CBS in Injury Time Estimation after Brain Contusion]

OBJECTIVES

To observe the changes of cystathionine β-synthase （CBS） expression in the cerebral cortex after brain contusion at different times.

METHODS

An experimental model of traumatic brain injury （TBI） in mice was established by an improved weight-drop device. Then Western blotting and immunohistochemical examination were used to detect the CBS expression in cerebral cortex around injury at different time points （1 h, 6 h, 12 h, 1 d, 2 d, 3 d, 7 d）.

RESULTS

The results of Western blotting revealed that the expression level of CBS was down-regulated and reached its lowest level at the 3rd days after injury, and then restored to normal level after 7 days. The results of immunohistochemistry showed that CBS was present in the normal brain cortex. CBS expression gradually decreased at the 3rd days after injury, and then restored to normal level after 7 days.

CONCLUSIONS

CBS has the potential to be a reference index for time estimation after brain contusion in forensic practice.

[Effects of AF64A on neurons containing both nitric oxide synthase and choline acetyltransferase in the rat septal complex]

Ethylcholine mustard aziridinium ion (AF64A), a neurotoxic choline analog, was injected (ICV) bilaterally (1.5 nmol/ventricle, n = 10) into male adult rats to induce a model of Alzheimer's disease (AD). One month later, using NADPH-diaphorase (NADPH-d) histochemistry followed by choline acetyltransferase (ChAT) immunocytochemistry (PAP) on the coronal sections of the septal complex, double-staining experiments were performed to assay the alterations of septal cholinergic neurons coexisted with nitric oxide synthase (NOS). Compared to controls, AF64A can significantly reduce the numbers of ChAT single labelled neurons and NADPH-d + ChAT double labelled neurons in the dorsal subgroup (29.5% and 26.7%, respectively, P < 0.01). Moreover, the dendrites of these neurons were damaged. While administration of AF64A resulted in a significant decrease in the number of ChAT single labelled neurons (35.2%, P < 0.01) in the intermediate subgroup (rostral extension of the nucleus/substantia innominata) NADPH-d + ChAT double labelled neurons were unchanged (P > 0.05). In the midline and the ventral subgroups, both of these two kinds of cholinergic neurons were not affected significantly by AF64A (P > 0.05). Furthermore, AF64A had no effect on NADPH-diaphorase single labelled neurons in all subgroups of septal complex. These results indicate that: (1) the administration of AF64A has different effects on the cholinergic neurons with or without NOS in different subgroups of the septal complex, and the NADPH-d + ChAT double labelled neurons resist the neurotoxicity of AF64A; (2) in the intermediate subgroup, the cholinergic neurons containing NOS may have projections different from those without NOS.