Morphological and functional changes in the blood-spinal cord barrier of rabbits in an experimental spinal cord presyrinx state

BACKGROUND: Presyrinx state of spinal cord can reflect the initial lesion of syringomyelia (SM). The early trials has proved that ischamia and edema are main pathological changes of presyrinx state. OBJECTIVE: To establish SM model of rabbits for investigating the relationship between changes of morphous and function of blood-spinal cord barrier and the edema degree, histological changes in presyrinx state of SM, and to explore the mechanism of the presyrinx state of SM. DESIGN: Randomized controlled animal experiment. SETTING: Department of Neurosurgery, Fourth Hospital, Heibei Medical University. MATERIALS: Sixty Chinese healthy white rabbits, aged 3.5-4.5 months, weighing 1.5-2.0 kg, were provided by Experimental Animal Center of Hebei Medical University [certification: (SYXK(Ji)2003-0026)]. Evan's blue (EB) and dimethylformamide (DMF) were purchased from Jingmei Biotech Co., Ltd. RM2125 paraffin section cutter (Leica Company, Japan), H-7500 transmission electron microscope (Hitachi Company, Japan), PM-20 light microscope photograph system (Olympus Company, Japan). METHODS: The experiment was carried out in the Laboratory of Neurosurgery Department, Second Hospital of Hebei Medical University from January to June 2006. ① All the rabbits were randomly divided into two groups: model group (n =40), control group (n =20). Rabbits in two groups were divided into five subgroups once again at five time points (1st, 3rd, 7th, 14th, 21st days, n =8 and n =4 at each time point in the model group and control group, respectively). Under ketamine anesthesia, 0.6 mL Kaolin solution (250 g/L, 37 ℃) was injected into the cisterna magna of rabbits in model group, while 0.6 mL physiological saline (37 ℃) was injected into the rabbits of control group. ② On the 1st, 3rd, 7th, 14th, 21st days after kaolin injection, cervical cord samples were harvested after sacrifice of animal. Quantitative analysis on the function of blood-spinal cord barrier was performed by Evan's blue technique. Water content of spinal cord was measured by dry-wet weighing technique. Samples were fixed in 40 g/L paraform for haematoxylin and eosin staining. Pathological and ultramicrostructural observation was carried out under a light microscope and H-7500 electron microscope, respectively. ③ The comparison of measurement data was performed with analysis of variance. MAIN OUTCOME MEASURES: The changes of water content, Evan's blue content and pathology in upper cervical cord of presyrinx state at different time points. RESULTS: All the 60 rabbits were involved in the result analysis. ① Ultramicrostructural observation: During the whole process of occurrence and development of presyrinx state of spinal cord, no obvious morphological changes of blood-spinal cord barrier were found. Microvascular endothelial cells were in integrity in morphology, basal membrane was continuous and smooth, and the structure of tight junction was not destructed remarkably. ②Water content of spinal cord: Compared with control group, the water content of spinal cord was increased on the 1st day [(68.35±0.7)% vs.(66.51±0.32)%, F =7.387, P =0.026] after kaolin injection, more prominent on the 3rd day [(72.70±0.88)%, F =123.48, P =0.000], reached its peak on the 7th-14th day [(72.92±0.86)%, F =135.94, P =0.000; (72.18±0.55)%, F =28.18, P =0.001], and was declined slowly after 21 days[(70.03±0.77)%,F =11.51, P =0.009], but it was still higher than that of control group [(65.98±0.56)%, F = 11.51, P =0.009].③ Evan's blue content in spinal cord tissue: It started to rise on the 3rd day after operation [(2.79±0.42) mg/L, F =61.35, P =0.000], reached its peak on the 7th day [(3.53±0.45) mg/L, F =528.35, P =0.000], and kept this high level till the 14th day [(3.45± 0.35) mg/L, F =326.57, P =0.000]. It decreased on the 21st day [(3.36±0.27) mg/L], but was still higher than normal level[(1.69±0.16)mg/L,F = 58.63,P =0.000]. ④ Neurologic function score: The neurologic function score of rabbits in the model group was close to that in the control group preoperatively and on the postoperative 1st and 3rd days (F =2.667, P =0.141);Abnormal nerve function appeared on the postoperative 7th day (F =32.667, P =0.00), and the neurologic function scores were gradually decreased with the elongation of time. The neurologic function scores in the model group were significantly lower than those in the control group on the postoperative 14th and 21st days (F =42.667, 34.571,P =0.00). CONCLUSION: Under the presyrinx state of spinal cord of experimental rabbits, the destruction of blood-spinal cord barrier of spinal cord and spinal edema co-exist with the same changing tendency. Although morphological integrity of blood-spinal cord barrier is kept, the function of blood-spinal cord barrier was destroyed in the early stage and permeability is increased. This functional disorder plays an important role in the occurrence and development of presyrinx state of SM.

Regulatory effect of vascular endothelial growth factor on blood spinal cord barrier in presyrinx state of experimental syringomyelia

BACKGROUND： Vascular endothelial growth factor （VEGF） is able to regulate blood spinal cord barrier function as well as influence neovascularization and cause edema. OBJECTIVE： Through establishment of a rabbit model of syringomyelia, to explore the correlation between VEGF protein and mRNA expressions and function of blood spinal cord barrier and edema degree of spinal cord in presyrinx state. DESIGN, TIME AND SETTING： Randomized controlled animal study was performed in the Tumor Institute of the Fourth Hospital, Hebei Medical University from January to June 2007. MATERIALS： Atotal of 0.6 mL Kaolin solution （250 g/L, 37℃） was injected into the cisterna magna of 40 rabbits in the kaolin group to establish syringomyelia models. Goat anti-rabbit VEGF monoclonal antibody was provided by DIACLONE Company, USA; RT-PCR related reagents were provided by Huamei Bioengineering Co., Ltd., Beijing. METHODS： Sixty Chinese white rabbits were divided randomly into two groups： Kaolin group （n = 40） and control group （n = 20）. Physiological saline （0.6 mL at 37℃） was injected in rabbits of control group. On days 1,3, 7, 14 and 21 after kaolin injection, cervical cords samples were harvested after sacrifice of animal. MAIN OUTCOME MEASURES： VEGF protein and mRNA expressions were detected by immunohistochemistry and RT-PCR on days 1, 3, 7, 14, and 21 after kaolin injection. A quantitative analysis of blood spinal cord barrier function was performed by Evans blue technique. Water content of the spinal cord was measured by dry-wet weight technique. The correlation between the expression of VEGF protein and mRNA and the function of blood spinal cord barrier in the upper cervical cord of the presyrinx state was analyzed by linear correlation analysis. RESULTS： The water content and Evans blue content increased in the kaolin group on days 1 and 3 postoperatively compared with the control group （F = 7.387, 61.35, P 〈 0.05, 0.01）, and reached a peak on day 7 （F = 135.94, 528.35, P 〈 0.01）. They declined slowly to day 21 postoperatively, but both contents were still higher than the control group （F = 11.51, 58.63, P 〈 0.01）. VEGF protein expression increased on day 1, and stronger positive expression was seen on days 3, 7 and 14. It decreased on day 21. VEGF protein expression was higher than the control group at each time point （F = 137.4-468.5, P 〈 0.01 ）. VEGF mRNA expression showed the same pattern in the cervical cord at different time points. By statistical analysis, the expression of VEGF protein and mRNA had a significantly positive correlation with the structural and functional changes of the blood spinal cord barrier in the presyrinx state （r = 0.604-0.979, P 〈 0.05）. CONCLUSION： In the presyrinx state of syringomyelia, the expressions of VEGF protein and mRNA can influence the structure and function of the blood spinal cord barrier and play an important role in the formation and development of spinal cord edema and syringomyelia.

NF-κB和IκB对兔实验性脊髓空洞前状态神经元凋亡的影响

目的 探讨NF-κB、IκB在兔脊髓空洞前状态神经元凋亡中的作用.方法 成年新西兰大白兔,用TUNEL法和免疫组化检测脊髓神经元凋亡和NF-κB、IκB、BCL-2、BAX表达.结果 Kaolin组动物在术后各个时段均有神经元凋亡发生,以7～14 d最为多见;NF-κB于术后1天就有表达增高,第3天达到高峰,维持至第7天后开始回落,14 d时基本恢复正常水平;IκB表达与NF-κB表达呈负相关;BCL-2表达则于术后1 d开始增加,到术后7 d达高峰,持续至14 d后下降.BAX表达趋势与BCL-2相似,但明显强于后者.结论 脊髓空洞前状态发展过程中,NF-κB表达增高,可能主要上调其靶基因BAX,诱导神经元凋亡,参与了神经功能损害.

实验性脊髓空洞前状态蛋白激酶C的活性变化及意义

目的探讨蛋白激酶C(PKC)在脊髓空洞前状态中活性变化及其作用。方法用新西兰兔56只制作模型,术后1、3、7、14、21d用光镜、干湿重法观察上颈髓病理学演变、脊髓含水量,应用底物磷酸化法测定胞膜、胞浆PKC活性。结果高岭土组动物于术后第1天脊髓含水量即有明显增加[(68.35±0.70)%],第7天达到高峰[(72.92±0.86)%],持续到第14天,至第21天时稍有缓解[(70.03±0.77)%];组织学观察发现术后3d上颈髓轻度水肿,7～14d水肿达到高峰期,21d略有缓解;胞膜PKC活性术后1d出现增加(5.67±0.26pmol·mg-1·min-1),7～14d达到最高水平(13.27±3.15pmol·mg-1·min-1),21d开始回落(8.85±1.56pmol·mg-1·min-1),胞浆的PKC活性则呈相反趋势。结论脊髓空洞前状态形成中出现PKC移位激活,参与了缺血、缺氧性脊髓水肿的形成。

一种实验性脊髓空洞前状态动物模型的建立

目的:建立一种新西兰兔脊髓空洞前状态动物模型。方法:新西兰兔64只,随机分为Kaolin组、生理盐水组和假手术组,其中Kaolin组48只,经皮枕大池穿刺注入25%Kaolin混悬液0.6ml,分别于Kaolin注射后第1d、3d、7d、14d、21d、28d后常规行MRI观察后处死,取出上颈髓行组织学观察。结果:Kaolin组动物自Kaolin注入后3d出现缺血水肿(72.78±0.88%),7～14d达高峰(72.94±0.64%),21d减轻(70.21±0.49%);在T1WI表现为略低信号,T2WI为高信号且不能为FLAIR序列所抑制。至28d动物出现上颈髓空洞。结论:经皮枕大池Kaolin注射法可以制作出一种稳定性好、可重复率高的脊髓空洞前状态动物模型。

VEGF对实验性脊髓空洞前状态的血-脊髓屏障功能的调节作用

目的:通过建立兔脊髓空洞症模型,观察脊髓空洞前状态中血脊髓屏障功能变化和脊髓水肿程度,以及脊髓组织中VEGF蛋白、mRNA表达水平,并探讨VEGF表达在脊髓空洞前状态形成和发展中的作用。方法:应用干湿法测定脊髓空洞前状态中脊髓含水量,Evansblue法测定血脊髓屏障功能,应用免疫组织化学和RT-PCR测定脊髓组织中VEGF蛋白和mRNA的表达含量。结果:Kaolin组于术后第1天VEGFmRNA(0.31±0.02)表达有明显升高,第3天(0.44±0.03)、7天(0.66±0.02)、14天(0.56±0.01)呈强阳性表达,第21天(0.35±0.04)表达明显减弱;VEGF蛋白表达也呈现相同的变化趋势。同时Kaolin组动物在术后2周内出现脊髓水肿且随时间延长逐渐加重;组织中Evansblue含量在术后第3天有开始增高(2.79±0.42μg/ml),第7天达到高峰(3.53±0.45μg/ml),持续到第14天(3.45±0.35μg/ml),第21天有好转(3.36±0.27μg/ml)但仍高于正常。统计学分析结果显示VEGF高表达和脊髓空洞前状态中血脊髓屏障功能变化和脊髓水肿程度存在明显正相关。结论:在脊髓空洞前状态中,VEGF高表达对脊髓组织中血脊髓屏障功能和结构的破坏存在重要影响,在脊髓水肿和空洞形成、发展中起着重要作用。

兔脊髓空洞前状态神经细胞凋亡与Bcl-2、Bax蛋白表达的关系

目的探讨实验性脊髓空洞前状态（presyinx state）神经细胞凋亡及其与Bcl-2，Bax蛋白表达的关系。方法制作动物模型，用TUNEL法和免疫组化技术检测上颈髓神经细胞凋亡趋势和Bcl-2，Bax表达变化。结果Kaolin（高龄土、白陶土）组动物神经细胞凋亡于术后第1天出现增加。7—14d达高峰。以后逐渐降低，21d仍可见到凋亡发生；Bcl-2和Bax表达则于术后第1天开始增加。第7天达高峰。持续至第14天后下降。但主要以Bax表达增高为著。结论实验性脊髓空洞前状态演变过程中。主要上调其靶基因Bax诱导神经细胞凋亡。参与了脊髓的神经功能损害。

甲基强的松龙对兔脊髓空洞前状态神经细胞损伤的作用

目的:探讨甲基强的松龙(MP)对实验性脊髓空洞前状态神经细胞损伤的作用。方法:新西兰兔112只,随机分为对照组和MP干预组,每组56只,枕大池穿刺注入Kaolin制作脊髓空洞模型,其中MP干预组术后予以大剂量MP干预(第1～3天每天30mg/kg耳缘静脉缓慢注射,第4～7天改为每天10mg/kg),对照组术后不给药。术后1d、3d、7d、2周、3周、6周、9周行神经功能评分(Tarlov评分),并分别于相应时间点处死8只动物取材,应用光镜、电镜以及原位末端标记法(TUNEL法)对所取上颈髓标本分别行病理形态学、超微结构及神经细胞凋亡检查。结果:与对照组比较,MP干预组动物3d后Tarlov评分明显较高(P<0.05),上颈髓水肿程度较轻,高峰延迟,3d后脊髓含水量显著降低(P<0.05),同时神经细胞凋亡率显著下降(P<0.05)。空洞形成率MP干预组为37.5%,对照组为87.5%,两组比较存在显著性差异(P<0.05)。结论:应用甲基强的松龙干预对脊髓空洞前状态神经细胞损伤有明显的保护作用,有助于减少脊髓空洞形成。

实验性脊髓空洞前状态蛋白激酶C活性变化对NF-κB、IκB表达的影响

目的探讨蛋白激酶C（PKC）和核转录因子-κB（NF—κB）之间的关系及其在脊髓空洞前状态发病中的作用。方法用新西兰兔56只制作模型，术后1、3、7、14、21d用光镜观察上颈髓病理学演变；应用底物磷酸化法测定胞膜、胞浆PKC活性；应用免疫组化法测定NF—κB和IκB表达变化。结果高岭土组动物于术后第3d上颈髓轻度水肿，7—14d水肿达到高峰期，21d略有缓解；胞膜PKC活性术后1d出现增加（5．67±0．26pmol／mg／min），7—14d达到最高水平（13．27±3．15pmol／mg／min），21d开始回落（8．85±1．56pmol／mg／min），胞浆的PKC活性则呈相反趋势；NF—κB则于术后第1d明显升高（26．08％±2．36％），第7d达高峰（41．37％±3．22％），到两周时开始下降（37．56％±5．11％），IκB与NF-κB表达呈相反变化趋势。结论脊髓空洞前状态形成中出现PKC移位激活，可能通过激活NF—κB即PKC—NF—κB信号转导途径参与了脊髓空洞前状态的一系列病理过程。

实验性脊髓空洞前状态神经细胞死亡方式研究

目的：探讨实验性脊髓空洞前状态神经细胞死亡方式。方法：制作动物模型，术后1、3、7、14、21d处死，测定脊髓含水量，应用光镜、电镜和原位末端标记法（TUNEL法）观察上颈髓组织学、超微结构改变及神经细胞凋亡变化。结果：术后1～7天上颈髓主要为细胞毒性水肿：术后第14天出现水肿加重，出现线粒体和尼氏体等亚细胞结构损害；第21天出现前角细胞数量减少，胶质细胞增生，髓鞘板层状结构断裂，呈脱髓鞘改变，甚至轴索破坏。神经细胞凋亡于术后第1天出现增加，7～14天达高峰，以后逐渐降低，21天仍可见到凋亡发生。结论：脊髓空洞前状态发展过程中存在神经细胞坏死和凋亡，两者在脊髓空洞形成过程中起重要作用。

蛋白激酶C在实验性脊髓空洞前状态脊髓水肿中的作用

目的:探讨PKC在脊髓空洞前状态中脊髓水肿中的作用。方法:用新西兰兔制作模型,术后1、3、7、14、21d用光镜、干湿重法观察上颈髓病理学演变、脊髓含水量;应用底物磷酸化法测定胞膜、胞浆PKC活性;用伊文氏蓝(Evansblue)法定量测定血脊髓屏障损害程度。结果:Kaolin组动物于术后第1d脊髓含水量即有明显增加,第7d达到高峰,持续至14d,至21d时稍有缓解;胞膜PKC活性术后1d出现增加,7～14d达到最高水平,21d开始回落,胞浆的PKC活性则呈相反趋势;EB含量于第3d脊髓即有明显增加,第7d达到高峰,并持续到21d。结论:脊髓空洞前状态形成中出现PKC移位激活,参与了缺血、缺氧性脊髓水肿的形成。

TGF-β1在脊髓空洞前状态的表达变化研究

目的用免疫组化技术动态观察新西兰白兔脊髓空洞症模型中TGF-β1的表达情况,探讨其在脊髓空洞前状态形成中的作用机制。方法将90只健康、体重1. 5～2 kg的新西兰白兔(雌雄不限),随机分为Kaolin组、0. 9%氯化钠溶液组和对照组,每组30只。于术后第1、3、7、10、14天后处死,迅速完整取出C1-2节段4 mm,置4%多聚甲醛后固定48 h,供TGF-β1免疫组织化学染色检查。用HPIAS-1000高清晰度彩色病理图文分析系统对TGF-β1阳性反应物积分光密度值(IOD)进行半定量检测,进行统计分析。结果 TGF-β1免疫组织化学检测发现,对照组和0. 9%氯化钠溶液组动物颈髓灰质和白质神经元及胶质细胞均有弱阳性表达。Kaolin组动物于术后第1天上颈髓组织神经元表达有明显升高,神经胶质细胞亦可见阳性表达,主要为胞浆表达;第3天、7天、10天在上颈髓灰质及白质神经元、神经胶质细胞呈强阳性表达,胞浆可见粗的棕黄色颗分布,以第10天最为显著。第14天则TGF-β1表达稍微减弱。0. 9%氯化钠溶液组和对照组TGF-β1表达的IOD测定差异无统计学意义(P> 0. 05); Kaolin组动物颈髓组织中TGF-β1表达与0. 9%氯化钠溶液组和对照组相比明显升高,其中以第10天最为显著(P <0. 01)。结论本实验结果显示在脊髓空洞形成早期,脊髓组织TGF-β1表达上调,提示其在脊髓空洞前状态病理生理形成过程中可能发挥重要作用。

蛋白激酶C对Bcl-2、Bax调控兔脊髓空洞前状态神经元凋亡的影响

目的探讨蛋白激酶C(PKC)对Bcl-2、Bax调控兔脊髓空洞前状态神经元凋亡的影响。方法用成年新西兰白兔制作模型,术后1、3、7、14、21 d,用底物磷酸化法测定胞膜、胞质PKC活性;用TUNEL法和免疫组化检测脊髓神经元凋亡和Bcl-2、Bax表达。结果 Kaolin组动物胞膜PKC活性术后1 d出现增加〔(5.67±0.26)pmol.mg-1.min-1〕,7～14 d达到最高水平〔(13.27±3.15)pmol.mg-1.min-1〕,21 d开始回落〔(8.85±1.56)pmol.mg-1.min-1〕,胞质的PKC活性则呈相反趋势;同时受试动物术后各个时点上颈髓均有神经元凋亡发生,以7～14 d最为多见〔(37.75±4.36)%〕;Bcl-2和Bax表达均于术后1 d开始增加〔(7.50±1.15)%;(18.27±2.55)%〕,到术后7 d达高峰〔(17.64±4.52)%;(40.29±3.68)%〕,持续至14 d后下降。但后者明显强于前者。结论脊髓空洞前状态发展过程中,出现了PKC的转位激活,其通过直接或间接途径上调Bcl-2和Bax表达,主要上调Bax,诱导神经元凋亡,参与了神经功能损害。

兔脊髓空洞前状态蛋白激酶C对水通道蛋白4表达的调控作用

目的探讨PKC在脊髓空洞前状态中活性变化及其对AQP4调控作用。方法用新西兰兔56只制作模型,术后1、3、7、14、21d用免疫组织化学技术检测AQP4表达变化、应用底物磷酸化法测定胞膜、胞浆PKC活性。结果 Kaolin组动物AQP4于术后3 d开始减弱(IA 320．5± 44．2),7-14 d达到最低水平(IA 258．7±26．5),到21 d时有所回升(IA 321．5±46．1);胞膜PKC 活性术后1 d出现增加每分钟(5.67±0．26)pmol／mg,7-14 d达到最高水平每分钟(13．27±3．15 pmol／mg),21 d开始回落每分钟(8．85±1．56)pmol／mg,胞浆的PKC活性则呈相反趋势。结论脊髓空洞前状态形成中出现PKC移位激活,对AQP4进行磷酸化,参与了缺血、缺氧性脊髓水肿的形成。

兔脊髓空洞前状态水通道蛋白-4表达变化与脊髓水肿的关系

目的探讨脊髓空洞前状态AQP4表达变化与脊髓水肿演变的关系。方法用新西兰兔56只枕大池注入Kaolin制作动物模型,术后1、3、7、14、21 d用干湿重法、免疫组织化学和原位杂交技术检测脊髓空洞前状态脊髓含水量、AQP4及其mRNA表达变化。结果Kaolin组动物于术后第1天脊髓含水量即有明显增加(68.35±0.70)%,第7天达到高峰(72.92±0.86)%,21 d稍有缓解(70.03±0.77)%,但仍高于对照组;AQP-4于术后第1天开始减弱(IA 320.5±44.2),第7～14天达到最低水平(IA 258.7±26.5),到21 d时回升(IA 321.5±46.1),但仍低于对照组;而AQP4 mRNA表达变化趋势与其蛋白含量变化相一致。线性回归分析发现,AQP4及其mRNA表达变化与脊髓含水量之间存在负相关(r=-0.769,P<0.01;r=-0.854,P<0.01)。结论脊髓空洞前状态中AQP4及其mRNA下调可能参与了脊髓水肿的形成。

紧密连接蛋白ZO-1在兔脊髓空洞前状态中的表达

目的观察紧密连接蛋白ZO-1在实验性兔脊髓空洞前状态中的表达及变化规律。方法通过Kaolin枕大池注射,建立兔脊髓空洞模型,分别在术后第1、3、7、14、21天,应用Evans- blue法、免疫组织化学和Western blot测定60只(实验组40只,对照组20只)中国白兔血脊髓屏障功能、上颈髓中ZO-1表达含量,并探讨其内在相关性。结果与对照组比较,实验组动物脊髓组织中Evansblue含量在术后第3天开始增高(2.79±0.42)mg/L,7 d达到高峰(3.53±0.45)mg/L,持续到14 d(3.45±0.35)mg/L,21 d好转(3.36±0.27)mg/L。Western blot结果显示,ZO-1表达含量在第3天开始减弱(195.32±23.50),第7天(126.28±27.40)、14 d(119.36±18.70)表达最弱,21 d(165.70±21.20)部分恢复。同时免疫组织化学测定ZO-1表达变化趋势和Western blot结果一致。统计学分析表明,ZO-1表达与Evansblue含量在空洞前状态中的时相变化具有明显相关性(r=-0.9502,P<0.01)。结论ZO-1的表达强度变化趋势与实验性兔脊髓空洞前状态中的血脊髓屏障功能破坏程度变化相一致,ZO-1表达下降是形成实验性脊髓空洞前状态病理改变的重要因素。

大剂量甲基强的松龙对脊髓空洞前状态AQP4表达的影响

目的探讨大剂量甲基强的松龙(MP)对AQP4表达的影响及其对实验性脊髓空洞前状态脊髓水肿的保护机制。方法选用新西兰白兔,制作动物模型并应用大剂量MP干预,采用干湿重法测定脊髓含水量,用免疫组化、Western blot和RT-PCR技术检测脊髓空洞前状态AQP4及其mRNA表达变化。结果Kaolin组动物于术后第1天脊髓含水量即有明显增加,第7天达到高峰, 21d时稍有缓解;AQP4于术后第1天开始减弱,第7-14天达到最低水平,到21d时回升;而AQP4 mRNA表达变化趋势与其蛋白含量变化相一致。MP组动物脊髓水肿时间延迟,程度显著减轻,上颈髓AQP4及其mRNA明显增高,以7d、14d最为显著。结论MP能够在基因和蛋白水平增加AQP4表达,促进水分子向血管腔和蛛网膜下腔转运,发挥抑制脊髓水肿作用。

大剂量甲波尼松龙对兔脊髓空洞前状态蛋白激酶C活性变化的影响

目的观察大剂量甲波尼松龙对脊髓空洞前状态蛋白激酶C(PKC)活性变化的影响。方法用新西兰兔96只制作模型,随机分为Kaolin组、MP干预组,其中后者用大剂量甲波尼松龙(30 mg/kg体重)干预。术后1、3、7、14、21 d用光镜、干湿重法和底物磷酸化法观察两组动物上颈髓病理学演变、脊髓含水量以及胞膜、胞质PKC活性。结果与Kaolin组比较,MP干预组动物上颈髓水肿程度减轻,高峰延迟,脊髓含水量显著降低,以3 d的含水量(68.66±0.37)%和Tar- lov评分(5.00±0.00)改善最为明显,同时胞膜和胞质PKC活性明显下降,以7 d[(5.76±0.45)/ (3.41±0.54)pmol·mg^(-1)·min^(-1])和14 d[(6.21±0.40)/(3.77±0.31)pmol·mg^(-1)·min^(-1])最为显著,下降达50%。结论大剂量甲波尼松龙通过抑制脊髓空洞前状态PKC移位激活、降低PKC活性发挥对空洞前状态脊髓缺血、水肿的保护作用。