RESUMO
Objective To observe the regulatory effect of olfactory ensheathing cells (OECs) on polarization of M2 macrophages after acute contusion of spinal cords in rats,and explore the mechanism of OECs transplantation in promoting repair of spinal cord injury.Methods The primary OECs were isolated and cultured for transplantation.The T10 spinal cords of SD rats were exposed and impacted by impact stick (10 g) dropping vertically from a height of 25 mm with a NYU-Ⅱ impactor.Twenty-four rats with contusion of spinal cord immediately after injury were randomly divided into DMEM/F12 control group and OECs transplantation group according a random number table.DMEM/F12 culture medium or OECs suspension (3×104/μL,1 μL×3 times) was implanted into the injured spinal cords.At one to 9 weeks after injury,Basso Beattie Bresnahan (BBB) scale was used to evaluate the motor functions in rats.At one week after injury,M2 macrophages and Nogo-A positive cells were labeled by immunofluorescence staining;the expressions of interleukin (IL)-4 and IL-6 were detected by Western blotting.At 9 weeks after injury,the pathological changes of injured spinal cords were observed by HE staining.Results One and 9 weeks after injury,BBB scores in OECs transplantation group were significantly higher than those in control group at each time point after injury (P＜0.05).One week after injury,the number of M2 macrophages in OECs transplantation group was significantly larger than that in control group (3.24％ ±0.56％ vs.0.63％ ±0.21％),and the number of Nogo-A positive cells was significantly smaller and fluorescence intensity was significantly lower in OECs transplantation group than those in control group ([43±24] field vs.([207±88]/field;0.042±0.006 vs.0.062±0.011,P＜0.05);the IL-4 protein level was significantly higher and the IL-6 protein level was significantly lower in OECs transplantation group than those in the control group (0.717±0.152 vs.0.183±0.063;0.550±0.124 vs.1.060±0.209;P＜0.05).Nine weeks after injury,the cytoplasmic cavity area in OECs transplantation group ([1.511±0.581] mm2) was significantly lower than that in control group [2.939±0.823] mm2,P＜0.05).Conclusion OECs transplantation may promote macrophages polarizing to subtype M2,improve the microenvironment of inflammation,reduce Nogo-A secretion,thus promote the structure and spinal cord function recovery.
RESUMO
Objective To study the characteristics of craniocerebral injury caused by the handgun bullet impacting on the bulletproof helmet.Methods Fourteen healthy landrace pigs were involved and randomly divided into injury group(n =9)and control group(n =5).The landrace pigs of the injury group were shot vertically on the head under the protection of helmet plate with 9 mm handgun bullet at velocity of 360 m/s.While the landrace pigs of the control group were dealt with the same process as the injury group except for use of unarmed handgun bullet of the same ammunition dose.The changes of vital sign in the early period and the retina injury at two hours after injury were observed.Porcine cerebrospinal fluid (CSF)at pre-injury and at three hours post-injury were obtained for investigating the levels of neuron specific enolase(NSE)andαⅡ-spectrin protein.Then,the landrace pigs were sacrificed and dissected to examine the general morphological changes of the brain.The brain cortex was taken,fixed and stained with hematoxylin-eosin for microscopic observation.Results The landrace pigs in the injury group manifested decrease of the blood pressure and increase of the heart rate and respiratory rate in the early stage after injury.General morphological observation found retinal hemorrhage(3/9),skull fracture(3/9)and brain surface damage including local impact lesion(9/9)and contrecoup lesion(9/9),with severe impact lesion than contrecoup lesion.Optical microscopic observation revealed acute injury of the cerebral cortex neuron both on the impact and contrecoup locations.The concentrations of NSE and αⅡ-spectrinwere significantly increased in CSF three hours after injury(P ＜ 0.05).Conclusions The handgun bullet impacts on the pig head protected by the bulletproof helmet may induce blunt craniocerebral injury in the early period,with severe impact lesion than contrecoup lesion.Therefore,traumatic brain injury of the soldiers armed with the helmets should be stressed and managed early.