Objective To observe the expression of interleukin-1β (IL-1β) in blood serum after axonal injury in rats and investigate the effects of ciclosporin A (CsA) on it so as to discuss mechanism of CsA protecting neural function. Methods A total of 75 adult male SD rats were randomly divided into control group (Group A with 5 rats), only optic nerve stretch group (Group B with 35 rats) and stretch plus CsA treatment group (Group C with 35 rats). Stretch injury was induced in the right optic nerves of the rats in Group B and C. CsA at 20 mg/L was intraperitonealy injected in Group C immediately after stretch injury. Five animals from both Group B and Group C were killed at 1,3, 6, 12 hours and at days 1,3 and 7 after stretch injury or injection of CsA respectively. Morphological changes of optic nerves and retinal ganglion cells (RGCs) after stretch injury were examined under light microscope. In the mean- time, expression of IL-1β in the blood serum was observed by means of radioimmunoassay. Results (1) Histopathological observation showed lose of R GCs at day 3 and disarranged nerve fiber at day 7 after stretch injury of optic nerve in Group B, but significant amelioration of corresponding changes in Group C. (2) The expression of IL-1β in blood serum in Group B was significantly higher than that in Group A 3, 6, 12 hours and 1 day after injury. The expression of IL-1β reached peak at the 6th hour, then de- creased gradually and returned to the similar level of Group A after 3 days. The expression pattem of IL- 1 β in blood serum of Group C decreased more significantly at 3, 6, 12 hours and 1 day compared with that in Group B but was still higher than that of Group A at 6, 12 hours and 1 day. Conclusions The long-term and excessive expression of IL-1β may be involved in the secondary pathological changes after axonal injury. CsA exerts neuroprotective effect on injured axons mostly by attenuation of inflammation re- action after axonal injury.

BACKGROUND: At present, traditional modalities of neuroimaging, such as CT and MRI, is very limited in the diagnosis and severity estimation of diffuse axonal injury (DAI).OBJECTIVE: To investigate the value of proton magnetic resonance spectroscopy (1HMRS) in the diagnosis and prognosis of DAI.DESIGN, TIME AND SETTING: Prospective clinical controlled observation. The study was performed at the Department of Neurosurgery, and Department of Radiology, First Affiliated Hospital of Chongqing Medical University between October 2002 and September 2007.PARTICIPANTS: A total of 63 subjects with traumatic brain injury were enrolled and divided into DAI group (n=27) and non-DAI group (n=36) according to the result of MRI. In addition, 20 healthy persons were served as control group.METHODS: Demographic and clinical data were recorded on admission and neuroimaging examinations including fluid attenuated inversion recovery were carried on according to carefully designed procedures, in addition, 1HMRS was performed and the data were analyzed in combination with clinical condition.MAIN OUTCOME MEASURES: The ratios of N-acetyl aspartate (NAA)/creatine (Cr) and creatine phosphate (Cr), Choline compound (Cho)/Cr, myoinositol (mlNs)/Cr, and glutamic acid (GIx)/Cr at genu and splenium of corpus cellosum, and basal ganglia were quantified using 1HMRS.RESULTS: Compared with control and non-DAI groups, DAI group had decreased NAA/Cr and increased Cho/Cr at genu and splenium of corpus callosum, and basal ganglia (P < 0.05- 0.01), as well as increased mlNs/Cr and Glx/Cr at genu and splenium of corpus cellosum (P < 0.05). Non-DAI group also showed decreased NAA/Cr at splenium and increased Cho/Cr at genu of corpus callosum compared with control group (P < 0.01), but the change degree was less than DAI group. A positive correlation between Cho/Cr at genu of corpus callosum and the peded of primary unconsciousness was identified in DAI group (r=0.824, P < 0.01). CONCLUSION: The 1HMRS indexes at genu and splenium of corpus callosum, and basal ganglia could serve as effective indexes for the diagnosis of DAI. The Cho/Cr could well reflect histological changes following injury and act as sensitive index to predict clinical injury.