大鼠脑出血后IL-1β和CD163/HO-1信号通路表达及其与脑水肿的相关性

目的探讨脑出血后CD163/HO-1信号通路与IL-1β表达的动态变化,分析其与脑水肿的关系。方法 SD大鼠90只,随机分为正常对照组、假手术组、模型组、分别在造模后24小时、72小时、7天处死动物,免疫组化法检测HO-1、CD163、IL-1β的表达,并测定脑组织含水量。结果 ICH大鼠模型组24h后灶周可见IL-1β、HO-1、CD163阳性细胞增多,IL-1β阳性细胞数脑出血组与假手术组相比增多(P0.01),假手术组IL-1β阳性细胞数多于正常对照组(P0.01)。HO-1阳性细胞数脑出血组、假手术组均高于正常对照组(P0.01),脑出血组高于假手术组,在72小时明显增多(P0.01),CD163假手术组在72小时高于正常对照组(P0.01),各时间点脑出血组明显高于假手术组及正常对照组(P0.01)。脑组织含水量72小时最高,与HO-1、CD163正相关(P0.05)。结论 CD163、HO-1与ICH后炎性因子IL-1β的表达相关,CD163/HO-1信号通路与ICH后脑水肿有关。     

Improvement in neurological outcome after administration of atorvastatin following experimental intracerebral hemorrhage in rats

OBJECT: Atorvastatin, a beta-hydroxy-beta-methylglutaryl coenzyme A reductase inhibitor, improves neurological functional outcome, reduces cerebral cell loss, and promotes regional cellular plasticity when administered after intracerebral hemorrhage (ICH) in rats. METHODS: Autologous blood was stereotactically injected into the right striatum in rats, and atorvastatin was administered orally beginning 24 hours after ICH and continued daily for 1 week. At a dose of 2 mg/kg, atorvastatin significantly reduced the severity of neurological deficit from 2 to 4 weeks after ICH. The area of cell loss in the ipsilateral striatum was also significantly reduced in these animals. Consistent with previous study data, higher doses of atorvastatin (8 mg/kg) did not improve functional outcome or reduce the extent of injury. Histochemical stains for markers of synaptogenesis, immature neurons, and neuronal migration revealed increased labeling in the region of hemorrhage in the atorvastatin-treated rats. CONCLUSIONS: Analysis of the data in this study indicates that atorvastatin improves neurological recovery after experimental ICH and may do so in part by increasing neuronal plasticity.     

Serial change of cerebral blood flow after collagenase induced intracerebral hemorrhage in rats]

In case of intracerebral hemorrhage (ICH), many clinical studies have reported that great alterations in regional cerebral blood flow (rCBF) have been observed not only in the acute but also in the chronic stage. However, due to the absence of reproducible animal model, experimental studies have failed to confirm the evidence. We therefore studied the serial change of rCBF and investigated the possibility of secondary brain damage using our collagenase induced ICH model. A total of 60 adult male rats were examined. 2 microliters artificial cerebrospinal fluid, which was adjusted to a pH 7.4 by a buffer, containing 0.25 units of bacterial collagenase was stereotactically injected into the left caudoputamen in 28 rats. 2 microliters artificial cerebrospinal fluid without collagenase was also injected into 28 control rats under sham operation. The remaining 4 rats were studied as a non treatment group. The rCBF of the frontal cortex, parietal cortex, temporal cortex, occipital cortex, caudoputamen, thalamus and the cerebellum was determined bilaterally by [14C]-iodoantipyrine quantitative autoradiography according to Sakurada's method at 2, 4, 12, 24, 48, 168 and 720 hours after the operation. At 4 hours after injection, significant decrease of rCBF was observed in the ipsilateral hemisphere and also in some contralateral regions. In the ipsilateral frontal cortex and caudoputamen, there was significant increase of the rCBF which reached close to the baseline at 24 hours. After that, the rCBF of those regions decreased significantly again and remained at a low value even 1 month after injection. In the other regions of the ipsilateral hemisphere which were located remotedly from the hematoma, the rCBF recovered from 24 to 48 hours after injection. In the contralateral hemisphere, the rCBF also recovered at 24 hours. We suggest that this alteration of the rCBF observed in perihematomatous regions was the result of secondary brain damage caused by the existence of hematoma. On account of this, we conclude that early removal of hematoma is necessary to obtain a better result in cases of ICH.     

Brain edema after experimental intracerebral hemorrhage: role of hemoglobin degradation products

OBJECT: The mechanisms involved in brain edema formation following intracerebral hemorrhage (ICH) have not been fully elucidated. The authors have found that red blood cell lysis plays an important role in edema development after ICH. In the present study, they sought to determine whether degradation products of hemoglobin cause brain edema. METHODS: Hemoglobin, hemin, bilirubin, or FeCl2 were infused with stereotactic guidance into the right basal ganglia of Sprague-Dawley rats. The animals were killed 24 hours later to determine brain water and ion contents. Western blot analysis and immunohistochemistry were applied for heme oxygenase-1 (HO-1) measurement. The effects of an HO inhibitor, tin-protoporphyrin (SnPP), and the iron chelator deferoxamine, on hemoglobin-induced brain edema were also examined. Intracerebral infusion of hemoglobin, hemin, bilirubin, or FeCl2 caused an increase in brain water content at 24 hours. The HO-1 was upregulated after hemoglobin infusion and HO inhibition by SnPP-attenuated hemoglobin-induced edema. Brain edema induced by hemoglobin was also attenuated by the intraperitoneal injection of 500 mg/kg deferoxamine. CONCLUSIONS: Hemoglobin causes brain edema, at least in part, through its degradation products. Limiting hemoglobin degradation coupled with the use of iron chelators may be a novel therapeutic approach to limit brain edema after ICH.     

多次给予羟乙基淀粉或高渗氯化钠溶液对实验性脑出血大鼠脑水肿的影响

目的 评价多次给予羟乙基淀粉或高渗氯化钠溶液对实验性脑出血(ICH)大鼠脑水肿的影响.方法 清洁级雄性SD大鼠167只,体重260～300 g,随机分为假手术组(S组,n=20)、ICH组(M组,n=38)、氯化钠组(N组,n=55)和羟乙基淀粉组(H组,n=54).采用立体定向技术向大鼠右侧尾状核注入自体血50μl建立ICH模型,S组仅刺入基底节,但不注血.N组分别于ICH后2、24、48、72 h前5～10 min静脉输注7.5%氯化钠溶液5 ml/kg,H组分别于ICH后2、24、48、72 h前45～50 min静脉输注6%羟乙基淀粉130/0.4 30 ml/kg,速率均为0.2 ml/min.S组和M组分别于ICH后2、24、48、72 h随机取5只大鼠断头处死,N组和H组则在上述各时点输液前、后随机取5只大鼠处死,采用干湿重法测定脑含水量;各组每天行行为学评分,观察大鼠生存情况.结果 与M组比较,N组和H组ICH后2、24、48、72 h输液后注血侧皮层和基底节脑含水量、ICH后24、48 h时行为学评分降低,ICH后24、48、72 h时生存率升高(P<0.05);与N组比较,H组ICH后72 h时生存率升高(P<0.05).结论 多次给予6%羟乙基淀粉130/0.4或7.5%氯化钠溶液可改善ICH后大鼠脑水肿.     

Ethanol-induced hypnotic tolerance is absent in N-methyl-D-aspartate receptor epsilon 1 subunit knockout mice

Recent pharmacological studies suggest that N-methyl-D-aspartate (NMDA) receptors play an important role in neuroadaptive processes in the development of tolerance to addictive drugs, such as opioids, amphetamine, and cocaine. In the present study, we investigated the contribution of the NMDA receptor to ethanol-induced hypnotic tolerance using NMDA receptor epsilon1 subunit knockout mice. Hypnotic sensitivity to a single injection of 3, 3.5, and 4 g/kg ethanol was not significantly different between wild-type mice and NMDA receptor epsilon1 subunit knockout mice. In contrast, although wild-type mice displayed hypnotic tolerance after repeated administration of 4 g/kg ethanol for 4 consecutive days, no change in the duration of hypnosis was observed in knockout mice. No significant differences were observed in blood ethanol clearance between wild-type and knockout mice on day 4. Our results indicate epsilon1 subunit containing the NMDA receptor might be involved in the development of ethanol-induced hypnotic tolerance.     

Heme oxygenase-2 deficiency contributes to diabetes-mediated increase in superoxide anion and renal dysfunction

Heme oxygenase-1 (HO-1) and -2 play an important role in cytoprotection and are physiologic regulators of heme-dependent protein synthesis in renal tissues. The impact of HO-2 deletion comparing hyperglycemic HO-2 (+/+) mice and HO-2 knockout (-/-) mice was examined. Hyperglycemia was induced by streptozotocin (STZ) injection, and its effect on renal HO-1/HO-2 protein, HO activity, and creatinine levels were assessed. The effect of HO induction using systemic administration of the HO inducers heme or cobalt protoporphyrin and the effect of HO inhibition using systemic administration of the HO inhibitor tin mesoporphyrin also were assessed in STZ-treated mice. In STZ-treated HO-2 (-/-) mice, there was marked renal functional impairment as reflected by an increase in plasma creatinine, associated with acute tubular damage and microvascular pathology as compared with HO-2 (+/+). In these animals, HO activity was decreased with a concomitant increase in superoxide anion. Upregulation of HO-1 in HO-2 (-/-) mice by weekly administration of cobalt protoporphyrin prevented the increase in plasma creatinine levels and tubulointerstitial and microvascular pathology. Inhibition of HO activity by administration of tin mesoporphyrin accentuated superoxide production and increased creatinine levels in hyperglycemic HO-2 (-/-) mice. In conclusion, HO-2 deficiency enhanced STZ-induced renal dysfunction and morphologic injury and HO-1 upregulation in HO-2 (-/-) mouse rescue and prevented the morphologic damage. These observations indicate that HO activity is essential in preserving renal function and morphology in STZ-induced diabetic mice probably via mitigation of concomitant oxidative stress.     

The Role of the Bcl-3 Proto-Oncogene in Thyroid Hormone-Induced Liver Cell Proliferation

The aim of the study was to determine if thyroid hormone-induced liver cell proliferation occurs through the Bcl-3 proto-oncogene. Rodents (including Bcl-3 knockout mice and the wild-type strain) were injected with a single dose of tri-iodothyronine (T₃) and sacrificed at various time points. Hepatic mRNA (real-time polymerase chain reaction ) and protein expression (Western analysis) of Bcl-3 was quantified in rats stimulated with T₃. Cell proliferation was induced in a variety of cell types after T₃ injection at 24 h including hepatocytes (7 ± 1.1% vs. 0.45 ± 0.025%; P  < 0.01), hepatic nonparenchymal cells (3.8 ± 1.2% vs. 0.3 ± 0.01%; P  < 0.01), renal tubular cells (8.1 ± 1.6% vs. 0.2 ± 0.035%; P  < 0.01), and splenic lymphocytes (4.8 ± 1.2% vs. 0.35 ± 0.02%; P  < 0.01). We showed a twofold increase in hepatic Bcl-3 mRNA ( P  < 0.01) and protein expression ( P  < 0.01) at 24 h in rats stimulated with T₃. However, there were no differences in the rate of liver cell proliferation between Bcl-3 knockout mice and the wild-type strain (0.4 ±  0.15% vs. 0.3 ± 0.1%), indicating that Bcl-3 was not functionally involved in thyroid hormone-induced liver cell proliferation. A single gene is unlikely to initiate the process of thyroid hormone-induced cell proliferation. A complex interaction between the genomic and nongenomic effects of thyroid hormone is likely to regulate the mitogenic effects.