丙酮酸乙酯对缺氧缺血性脑损伤新生大鼠脑组织的保护作用

 目的： 探讨丙酮酸乙酯（ethyl pyruvate, EP）对缺氧缺血性脑损伤（hypoxic-ischemic brain damage, HIBD）新生大鼠脑组织的作用及其可能机制。方法：165只7日龄SD大鼠随机分为3组:假手术组（n=43）、HIBD模型组（n=61）和HIBD+EP处理组（n=61）,造模前30 min腹腔注射EP（50 mg/kg）1次,此后每天1次,3 d后测定脑组织匀浆超氧化物歧化酶（SOD）活性和丙二醛（MDA）含量以及脑组织含水量,TUNEL法检测脑组织凋亡细胞数;14 d后检测缺血侧和非缺血侧脑重量以判别脑萎缩程度。结果：HIBD+EP组脑组织SOD活性为(125.78±18.35)×103 U/(g protein),较HIBD模型组［(97.84±15.50)×103 U/(g protein)］明显增强（P<0.05）;MDA含量为(4.42±1.04) μmol/(g protein),较HIBD模型组［(6.02±0.89) μmol/(g protein)］明显降低（P<0.05）。此外,HIBD模型组缺血侧（左侧）的脑组织含水量高于非缺血侧（右侧）（P<0.05）,EP治疗后两侧的脑组织含水量无显著差异（P>0.05）,提示EP减轻了缺血侧的脑水肿。同时HIBD+EP组缺血侧脑皮质和海马每个视野的凋亡细胞数目分别为96.63±10.08和41.91±9.96,较模型组（111.54±1.64和51.73±1.77）明显减少,但仍多于假手术组（P<0.05）。HIBD+EP组左脑萎缩程度为(13.25±5.19)%,较HIBD模型组［(20.32±5.10)%］明显减轻（P<0.05）。结论：EP具有抗氧化功能,能减轻脑水肿,减少脑细胞凋亡,减轻脑萎缩,对HIBD新生大鼠脑组织具有保护作用。     

Effect of glycine and glycine receptor antagonists on NMDA-induced brain injury

In postnatal day 7 rats, a unilateral intrastriatal injection of 12.5 nmol of N-methyl-D-aspartate (NMDA) reproducibly injures the ipsilateral striatum, adjacent hippocampus and overlying cortex. The severity of injury can be quantified by comparing cerebral hemisphere weights in animals sacrificed 5 days after the injection. Co-injection of NMDA and the glycine receptor antagonists kynurenic acid (KYN) or 7-chlorokynurenic acid (7-CKA) reduced the severity of NMDA-induced damage in a dose-dependent fashion. One hundred nmol of KYN with 12.5 nmol of NMDA reduced average % damage from 19.3 +/- 0.9% (n = 9) to 2.3 +/- 0.5% (n = 6), P less than 0.001, ANOVA. Co-injection of 40 nmol of 7-CKA with 12.5 nmol of NMDA (n = 6) reduced average % damage from 17.1 +/- 1.6% (n = 15) to 3.0 +/- 0.6%, P less than 0.001, ANOVA. Concurrent injection of 1000 nmol glycine with 5 nmol NMDA did not increase the extent of NMDA-induced damage. Our results demonstrate that glycine receptor antagonists attenuate NMDA-induced brain injury in vivo.     

Bax inhibiting peptide reduces apoptosis in neonatal rat hypoxic-ischemic brain damage

Neonatal hypoxic ischemic encephalopathy (HIE) has been reported to induce apoptosis in neonates. We, therefore, analyzed the ability of Bax-inhibiting peptide (BIP) to provide neuroprotective effects during hypoxic-ischemic brain damage (HIBD). Seven-day-old wistar rat pups (n = 198) were randomly divided into a sham-operated group (Group S, n = 18), saline group (Group C, n = 90) and BIP group (Group B, n = 90). Pathological changes in the cerebral tissues of rat pups were analyzed using hematoxylin and eosin stain, TUNEL and Western blot. The expression of cytochrome c and caspase-3 was determined using western blot technique. Rat pups demonstrated neurobehavioral alteration in Groups C and B. TUNEL-positive cells in the left hippocampus were significantly increased in Group C and Group B after HIBD (P < 0.01) when compared with Group S. There was a marked reduction in TUNEL positive cells in subgroups B1 through B4 when compared with the respective subgroups C1 through C5. Compared with Group S, the expression of caspase-3 and cytochrome c was significantly increased in Groups C and B (P < 0.01). The difference in expression of caspase-3 and cytochrome c between subgroups B1 through B4 and C1 through C4 was significant (P < 0.01). In conclusions, the neuro-protective effect of BIP was due to a reduction of nerve cell apoptosis in our neonatal HIE rat model. We propose that BIP has potential as a neuro-protective drug in neonatal HIE cases.     

Acute effects of resistance exercise and intermittent intense aerobic exercise on blood cell count and oxidative stress in trained middle-aged women

The aim of this study was to compare the effect of an intermittent intense aerobic exercise session and a resistance exercise session on blood cell counts and oxidative stress parameters in middle-aged women. Thirty-four women were selected and divided into three groups: RE group (performing 60 min of resistance exercises, N = 12), spinning group (performing 60 min of spinning, N = 12), and control group (not exercising regularly, N = 10). In both exercise groups, lymphocytes and monocytes decreased after 1-h recuperation (post-exercise) compared to immediately after exercise (P < 0.05). Immediately after exercise, in both exercised groups, a significant increase in TBARS (from 16.5 ± 2 to 25 ± 2 for the spinning group and from 18.6 ± 1 to 28.2 ± 3 nmol MDA/mL serum for the RE group) and protein carbonyl (from 1.0 ± 0.3 to 1.6 ± 0.2 for the spinning group and from 0.9 ± 0.2 to 1.5 ± 0.2 nmol/mg protein for the RE group) was observed (P < 0.05). A decrease in antioxidant activities (non-protein sulfhydryl, superoxide dismutase, catalase) was also demonstrated with a negative correlation between damage markers and antioxidant body defenses (P < 0.05). These results indicate that an acute bout of intermittent or anaerobic exercise induces immune suppression and increases the production of reactive oxygen species, causing oxidative stress in middle-aged and trained women. Furthermore, we demonstrated that trained women show improved antioxidant capacity and lower oxidative damage than sedentary ones, demonstrating the benefits of chronic regular physical activity.     

Different extent of hypoxic-ischemic brain damage in newborn rats: histopathology,hemodynamic, virtual touch tissue quantification and neurobehavioral observation

Objective: To explore the correlation between pathological and ultrasound changes applying conventional ultrasound, Color Doppler ultrasound andVirtual Touch Tissue Quantification (VTQ) technique in newborn hypoxic-ischemic brain damage (HIBD) rat models. To provide theoretical basis for early diagnosis and treatment of HIBD neonatal. Methods: A total of 90 newborn Wistar rats were divided into ischemia, asphyxia and control group according to different HIBD molding methods. Conventional ultrasound, Color Doppler ultrasound and VTQ were applied on 3 h, 12 h, 24 h, 48 h and 72 h postoperative. After the observation of 72 h, 10 rats in each group were randomly selected for pathological specimens production. The rest rats were raised for 30 days for neuroethology detection. Results: In ischemia group and asphyxia group, there were 4 deaths and 6 deaths in the modeling process; the mortality rate was 13.33% (4/30) and 20.00% (6/30) respectively. For ischemia group, the systoli velocity (Vs), diastolic velocity (Vd) and resistance index (RI) of right middle cerebral artery (MCA) were significantly decreased after operation (P<0.05). For asphyxia group, the Vs and RI of right MCA were significantly decreased after operation (P<0.05), while the Vd of right MCA was significantly increased after operation (P<0.05), which lead to the postoperative RI value in each time point was all significantly lower than that in ischemia group (P<0.05). For ischemia group and asphyxia group, the VTQ results increased significantly postoperative (P<0.05), and compared with ischemia group and control group, the postoperative VTQ value in each time point was all significantly higher in asphyxia group (P<0.05). The neuroethology results were significantly lower in the ischemia group and asphyxia group (P<0.05), and the results in ischemia group were significantly higher than those of asphyxia group (P<0.05). And the results are consistent with the pathological findings. Conclusion: There is a consistent correlation among histopathological changes, hemodynamic changes, VTQ values and neuroethology results in HIBD animal models. As noninvasive quantitative ultrasound elastography methods, Color Doppler ultrasound and VTQ can assess the extent of HIBD damages in newborn rats with specific values. This study provides basic research and theory to early diagnosis and early treatment of neonatal hypoxic-ischemic brain damage.     

咪哒唑仑对新生大鼠缺氧缺血性脑损伤的神经保护作用

目的 探究咪达唑仑(midazolam,Mida)对新生大鼠缺氧缺血性脑损伤(hypoxic-ischemic brain damage,HIBD)神经的保护作用.方法 建立HIBD新生大鼠模型,Mida处理后,行为实验评估大鼠的神经功能;2,3,5-三苯基四氮唑(TTC)检测大鼠脑梗死率,测量大鼠脑含水率和脑指数;苏...     

Early Toll-like receptor 4 inhibition improves immune dysfunction in the hippocampus after hypoxic-ischemic brain damage

Background: Toll-like receptor 4 (TLR4) is implicated in neonatal hypoxic-ischemic brain damage (HIBD), but the underlying mechanism is unclear.Hypothesis: We hypothesized that TLR4 mediates brain damage after hypoxic ischemia (HI) by inducing abnormal neuroimmune responses, including activation of immune cells and expression disorder of immune factors, while early inhibition of TLR4 can alleviate the neuroimmune dysfunction.Method: Postnatal day 7 rats were randomized into control, HI, and HI+TAK-242 (TAK-242) groups. The HIBD model was developed using the Rice-Vannucci method (the left side was the ipsilateral side of HI). TAK-242 (0.5 mg/kg) was given to rat pups in the TAK-242 group at 30 min before modeling. Immunofluorescence, immunohistochemistry, and western blotting were used to determine the TLR4 expression; the number of Iba-1+, GFAP+, CD161+, MPO+, and CD3+ cells; ICAM-1 and C3a expression; and interleukin (IL)-1β, tumor necrosis factor (TNF)-α, and IL-10 expression in the hippocampal CA1 region.Result: Significantly increased TLR4 expression was observed in the left hippocampus, and was alleviated by TAK-242. The significant increases in Iba-1+, MPO+, and CD161+ cells at 24 h and 7 days after HI and in GFAP+ and CD3+ T cells at 7 days after HI were also counteracted by TAK-242, but no significant differences were observed among groups at 24 h after HI. ICAM-1 expression increased 24 h after HI, while C3a expression decreased; TAK-242 also alleviated these changes. TNF-α and IL-1β expression increased, while IL-10 expression decreased at 24 h and 7 days after HI; TAK-242 counteracted the increased TNF-α and IL-1β expression at 24 h and the changes in IL-1β and IL-10 at 7 days, but induced no significant differences in IL-10 expression at 24 h and TNF-α expression at 7 days.Conclusion: Early TLR4 inhibition can alleviate hippocampal immune dysfunction after neonatal HIBD.     

Impairment of locomotor activity induced by the novel N-acylhydrazone derivatives LASSBio-785 and LASSBio-786 in mice

The N-acylhydrazone (NAH) analogues N-methyl 2-thienylidene 3,4-benzoylhydrazine (LASSBio-785) and N-benzyl 2-thienylidene 3,4-benzoylhydrazine (LASSBio-786) were prepared from 2-thienylidene 3,4-methylenedioxybenzoylhydrazine (LASSBio-294). The ability of LASSBio-785 and LASSBio-786 to decrease central nervous system activity was investigated in male Swiss mice. LASSBio-785 or LASSBio-786 (30 mg/kg, ip) reduced locomotor activity from 209 ± 26 (control) to 140 ± 18 (P < 0.05) or 146 ± 15 crossings/min (P < 0.05), respectively. LASSBio-785 (15 or 30 mg/kg, iv) also reduced locomotor activity from 200 ± 15 to 116 ± 29 (P < 0.05) or 60 ± 16 crossings/min (P < 0.01), respectively. Likewise, LASSBio-786 (15 or 30 mg/kg, iv) reduced locomotor activity from 200 ± 15 to 127 ± 10 (P < 0.01) or 96 ± 14 crossings/min (P < 0.01), respectively. Pretreatment with flumazenil (20 mg/kg, ip) prevented the locomotor impairment induced by NAH analogues (15 mg/kg, iv), providing evidence that the benzodiazepine (BDZ) receptor is involved. This finding was supported by the structural similarity of NAH analogues to midazolam. However, LASSBio-785 showed weak binding to the BDZ receptor. LASSBio-785 or LASSBio-786 (30 mg/kg, ip, n = 10) increased pentobarbital-induced sleeping time from 42 ± 5 (DMSO) to 66 ± 6 (P < 0.05) or 75 ± 4 min (P < 0.05), respectively. The dose required to achieve 50% hypnosis (HD₅₀) following iv injection of LASSBio-785 or LASSBio-786 was 15.8 or 9.5 mg/kg, respectively. These data suggest that both NAH analogues might be useful for the development of new neuroactive drugs for the treatment of insomnia or for use in conjunction with general anesthesia.     

miR-9在阿魏酸钠改善缺氧缺血性脑损伤大鼠学习记忆中的作用

目的:探讨miR-9在阿魏酸钠(SF)改善缺氧缺血性脑损伤新生大鼠学习记忆中对海马神经元NMDAR1和NgR1的调节作用。方法:88只7日龄SD大鼠随机分为假手术组(sham)、缺氧缺血性脑损伤组(HIBD)、阿魏酸钠治疗组(HIBD+SF)、miR-9抑制组(HIBD+LNA-miR-9),每组各22只。假手术组仅分离左侧颈总动脉,其余组结扎左侧颈总动脉进行缺氧后制作HIBD模型。于21日龄,阿魏酸钠治疗组连续5 d腹腔注射阿魏酸钠,miR-9抑制组经左侧脑室注射一次LNA-miR-9。于30日龄行Morris水迷宫检测各组大鼠空间学习记忆能力。于26日龄,real time RT-PCR检测各组大鼠左侧海马神经元miR-9、NMDAR1mRNA和NgR1mRNA的表达,Western Blot检测NMDAR1和NgR1蛋白的表达。结果:Morris水迷宫实验显示:与假手术组比较,HIBD组逃避潜伏期延长(P<0.05)、在目标象限逗留时间缩短(P<0.05);阿魏酸钠治疗组、miR-9抑制组较HIBD组均有逃避潜伏期缩短(P<0.05)、在目标象限逗留时间延长(P<0.05)。real time RT-PCR、Western Blot检测显示:HIBD组NMDAR1和NgR1的mRNA和蛋白表达以及miR-9表达较假手术组均明显上调(P<0.05);阿魏酸钠治疗组、miR-9抑制组较HIBD组各指标均明显下调(P<0.05)。结论:阿魏酸钠可能通过下调miR-9来抑制NMDAR1和NgR1的表达从而改善缺氧缺血大鼠的学习记忆能力。     

Chronic exposure to ammonia alters basal and NMDA-induced phosphorylation of NMDA receptor-subunit NR1

Hyperammonemia is responsible for many of the neurological alterations in patients with hepatic encephalopathy by mechanisms that remain unclear. Hyperammonemia alters phosphorylation of brain protein kinase C substrates and impairs N-methyl-d-aspartate (NMDA) receptor-associated signal transduction. The aim of this work was to analyze, in rat cerebellar neurons in culture, the effects of ammonia exposure on NMDA receptor phosphorylation, MK801 binding and surface expression. Ammonia reduces MK801 binding to NMDA receptors and the surface expression of the NR1 and NR2A subunits. As phosphorylation of serines in the NR1 C1 cassette has been implied in receptor trafficking, we assessed whether hyperammonemia alters phosphorylation of these serines. Basal phosphorylation of serines 890, 896 and 897 was increased in neurons exposed to ammonia, while NMDA-induced phosphorylation of S896 and S897 was reduced. Exposure to ammonia also increased basal phosphorylation of Akt but reduced NMDA and BDNF stimulation of Akt phosphorylation. These results suggest that alterations in receptor surface expression and possibly the phosphorylation state of the NR1 subunit of NMDA receptors may contribute to the impairment by ammonia of signal transduction pathways modulated by NMDA receptors.     

Hemodynamic mechanisms of the attenuated blood pressure response to mental stress after a single bout of maximal dynamic exercise in healthy subjects

To determine the hemodynamic mechanisms responsible for the attenuated blood pressure response to mental stress after exercise, 26 healthy sedentary individuals (age 29 ± 8 years) underwent the Stroop color-word test before and 60 min after a bout of maximal dynamic exercise on a treadmill. A subgroup (N = 11) underwent a time-control experiment without exercise. Blood pressure was continuously and noninvasively recorded by infrared finger photoplethysmography. Stroke volume was derived from pressure signals, and cardiac output and peripheral vascular resistance were calculated. Perceived mental stress scores were comparable between mental stress tests both in the exercise (P = 0.96) and control (P = 0.24) experiments. After exercise, the systolic blood pressure response to mental stress was attenuated (pre: 10 ± 13 vs post: 6 ± 7 mmHg; P < 0.01) along with lower values of systolic blood pressure (pre: 129 ± 3 vs post: 125 ± 3 mmHg; P < 0.05), stroke volume (pre: 89.4 ± 3.5 vs post: 76.8 ± 3.8 mL; P < 0.05), and cardiac output (pre: 7.00 ± 0.30 vs post: 6.51 ± 0.36 L/min; P < 0.05). Except for heart rate, the hemodynamic responses and the mean values during the two mental stress tests in the control experiment were similar (P > 0.05). In conclusion, a single bout of maximal dynamic exercise attenuates the blood pressure response to mental stress in healthy subjects, along with lower stroke volume and cardiac output, denoting an acute modulatory action of exercise on the central hemodynamic response to mental stress.     

Hyperbaric oxygenation promotes neural stem cell proliferation and protects the learning and memory ability in neonatal hypoxic-ischemic brain damage

The aim of our study was to evaluate whether hyperbaric oxygenation (HBO) was an effective therapy for neonatal hypoxic ischemic brain damage (HIBD). Seven-day-old rat pups were divided into 3 groups: sham, hypoxia-ischemia (HI) control and HI-HBO group. HBO was administered for HI rats daily. The pathologic changes in brain tissues were observed by hematoxylin-eosin (H-E) staining. The immunohistochemical staining was applied to detect the Nestin and 5-bromo-2-deoxyuridine (BrdU) positive cells in hippocampal dentate gyrus region. The learning and memory function of rats was examined by Morris water maze. The HI rats showed obvious pathologic changes accompanied by levels decreasing and disorder arrangement of pyramidal cells, glial cells proliferation in postoperative, and nerve nuclei broken, while pathologic changes of rats in sham group was approximate to that in the HI + HBO group that was opposite to the HI group. Compared with the sham group, the Nestin and BrdU positive cells in HBO + HI group at different time points increased significantly (P < 0.01). Learning and memory function of rats in HI group was poor compared with the sham/HI + HBO group (P < 0.01), while that in HI + HBO group was approximate to that in sham group (P > 0.05). HBO treatment improved the learning and memory ability of the HI rats. HBO therapy may be effective for neonatal HIBD treatment.     

腺苷A_(2A)受体拮抗剂SCH58261减轻胎兔缺氧缺血性脑损伤

目的:研究腺苷A_(2A)受体拮抗剂SCH58261减轻成熟胎兔缺氧缺血性脑损伤的作用。方法:选择孕29 d的普通级新西兰孕白兔随机分为假手术组(SO组)、缺氧缺血组(HI组)、SCH58261 0.04 mg/kg剂量组、SCH58261 0.12 mg/kg剂量组和药物溶剂组(DMSO组)。制备胎兔缺氧缺血性脑损伤模型,孕兔均在术后24 h行剖宫产,将存活新生兔置入已提前预热为35℃的婴儿暖箱内保暖。记录新生兔的一般状况;评估存活新生兔神经行为学改变;利用质谱法测孕兔血清、新生兔血清及脑组织的SCH58261浓度;采用real-time PCR检测新生兔脑组织皮质、海马和纹状体区Bcl-2和Bax的mRNA表达;利用Western blot实验检测新生兔脑组织皮质、海马和纹状体区p-P38 MAPK的蛋白水平。结果:新生兔血清和脑组织中均能检测到SCH58261的存在。与HI组比较,SCH0.04 mg/kg组和SCH 0.12 mg/kg组新生兔脑皮质、海马和纹状体区Bcl-2的mRNA表达均增加(P0.05),而Bax的mRNA的表达均减少(P0.05)。将p-P38 MAPK在新生兔脑皮质、海马和纹状体区的表达水平进行比较,SCH0.04 mg/kg组和SCH 0.12 mg/kg组的P38 MAPK磷酸化水平均低于HI组(P0.05),且SCH 0.12 mg/kg组与SCH 0.04 mg/kg组相比稍降低(P0.05)。结论:腺苷A_(2A)受体拮抗剂SCH58261可能通过阻断腺苷A_(2A)受体,抑制神经元P38 MAPK的磷酸化,进一步抑制脑细胞凋亡而减轻宫内缺氧缺血性脑损伤。     

Brain edema and protein expression of c-Fos and c-Jun in the brain after diffused brain injury

Objective: To investigate brain edema and protein expression of c-Fos and c-Jun in brain after diffuse brain injury, and to investigate the pathological change after brain injury, which may provide evidence for the clinical treatment of diffused brain injury. Methods: Marmarou method was used to establish the diffuse brain injury in rats. Results: After diffused brain injury, brain water content increased at 1 h, reached the peak at 1 d and remained at a high level at 7 d when compared with control group. One day after injury, diffuse subarachnoid hemorrhage was observed in the brain. HE staining showed vascular swelling and bleeding at the cortex and corpus callosum at 1 d. β-APP expression was found at the brainstem, hippocampus, thalamus, corpus callosum and periventricular regions. Pathological examination of ultrathin sections showed evidence edema and fracture of axons at 3 d after brain injury. The brain injury caused severe cerebral ischemia. The c-Fos and c-Jun expression increased at 1 h. The c-Fos expression peaked at 3 h (P < 0.05), then reduced, reached a maximal level again at 3 d (P < 0.05), and reduced significantly at 7 d but remained at a higher level when compared with control group (P < 0.05). The number of c-Jun positive cells peaked at 6 h (P < 0.05), then reduced, reached a maximal level again at 3 d and reduced markedly but still remained at a higher level when compared with control group (P < 0.05). Conclusion: After diffuse brain injury, brain water content and c-Fos/c-Jun expression change over time.     

The role of high mobility group box 1 (HMGB-1) in the diabetic retinopathy inflammation and apoptosis

Diabetic Retinopathy (DR) is one of the most common complications of the late phase diabetes, and also a common cause of blindness. High mobility group box 1 (HMGB-1) is considered to be an inflammatory mediator in the late phase that promotes inflammation and neovascularization in diabetes. Therefore, this paper discussed the role of HMGB-1 in diabetic retinopathy inflammation and neovascularization. 96 adult SD rats were randomly divided into control and diabetes group. The diabetic rat model was established by intraperitoneal injection of streptomycin (0.1 mol/L). Western blot was applied to determine HMGB-1 and its receptor RAGE and TLR2 protein expression in the serum. TUNEL was used to detect retinal apoptosis. Immunofluorescence was performed to test HMGB1 protein expression in retina. HBGM-1 and RAGE expression in diabetic rat retina was significantly higher than the control (P < 0.05), while TLR2 expression was lower (P < 0.05). TUNEL detection showed that diabetic rat retinal cells presented obviously higher apoptosis rate (P < 0.05). Immunofluorescence test revealed that HMGB1 largely expressed in the diabetic rat retinal cells (P < 0.05). HMGB1 may involve in the pathogenesis of diabetic retinopathy by binding with RAGE receptor to accelerate rat retinal cells apoptosis.     

缺氧缺血脑损伤大鼠脑组织Cofilin 1与ERK1/2蛋白表达与磷酸化的分析

目的探索新生大鼠缺氧缺血脑损伤模型脑组织Cofilin1与ERK1/2蛋白表达与磷酸化及其在脑组织中分布的规律。方法新生7日龄SD大鼠,手术结扎左侧颈总动脉并经低氧处理造成缺氧缺血脑损伤(HIBD)模型,以假手术组为对照,应用western Blot和免疫组化方法检测损伤后一定时间段(0h～48h)损伤侧脑组织Cofilin1与磷酸化cofilin1(p-Cofilin1)及Erk1/2和磷酸化ERK1/2(p-ERK1/2)的表达变化,同时检测其在损伤大鼠脑组织和细胞中的表达和分布。结果 Western blot检测显示,HIBD新生SD大鼠脑组织中Cofilin1在HI后的表达与对照组相比也未见明显改变,但磷酸化Cofilin1在HI后1h～12h之间降低,24h后恢复正常;ERK1/2蛋白在不同时点的表达与对照组相比未见明显差异,但可见磷酸化ERK1/2(p-ERK1/2)在缺氧缺血处理(HI)后0h略低于正常,而在1-2h内迅速升高并高于正常对照和假手术,在2h后又逐渐降低。免疫组化结果显示Cofilin1与p-cofilin1在损伤大鼠脑中主要分布于海马和大脑皮质,尤其p-Cofilin表达分布以海马的颗粒细胞为主,并且在HI后7d-14d表达明显增强,在21d则明显降低。结论 Cofilin和ERK的磷酸化修饰与缺氧缺血脑损伤的发生和发展过程有较密切的关系,且cofilin1和p-cofilin1在大脑海马区的定位分布,提示其可能与大脑的学习记忆功能的损伤与修复有一定的关系。     

天麻素对缺血缺氧脑损伤新生大鼠小胶质细胞Sirt3表达的影响

目的:研究天麻素对缺血缺氧脑损伤(HIBD)新生大鼠脑内激活的小胶质细胞Sirt3表达的影响。方法:选取39只3 d龄SD幼年大鼠随机分为对照组(control)、缺血缺氧脑损伤组(HIBD)、天麻素组(HIBD+gastrodin)。采用左侧颈总动脉结扎结合缺氧法建立新生大鼠缺血缺氧性脑损伤(HIBD)模型,使用免疫荧光染色观察HIBD模型后新生大鼠大脑胼胝体区小胶质细胞的分布情况;使用免疫荧光双标染色及Western Blot检测大鼠大脑左侧胼胝体区小胶质细胞Sirt3的表达变化。结果:免疫荧光染色结果显示HIBD后新生大鼠大脑左侧胼胝体区小胶质细胞出现明显激活,确定模型建立成功。免疫荧光双标染色及Western Blot结果均显示,与对照组相比,HIBD模型组Sirt3的表达水平明显升高(P<0.05);与HIBD模型组相比,天麻素组Sirt3的表达进一步增强(P<0.05)。结论:天麻素可能通过促进新生大鼠脑内小胶质细胞Sirt3的表达,发挥其神经保护作用。     

Hydrogen sulfide postconditioning protects isolated rat hearts against ischemia and reperfusion injury mediated by the JAK2/STAT3 survival pathway

The JAK2/STAT3 signal pathway is an important component of survivor activating factor enhancement (SAFE) pathway. The objective of the present study was to determine whether the JAK2/STAT3 signaling pathway participates in hydrogen sulfide (H₂S) postconditioning, protecting isolated rat hearts from ischemic-reperfusion injury. Male Sprague-Dawley rats (230-270 g) were divided into 6 groups (N = 14 per group): time-matched perfusion (Sham) group, ischemia/reperfusion (I/R) group, NaHS postconditioning group, NaHS with AG-490 group, AG-490 (5 µM) group, and dimethyl sulfoxide (DMSO; <0.2%) group. Langendorff-perfused rat hearts, with the exception of the Sham group, were subjected to 30 min of ischemia followed by 90 min of reperfusion after 20 min of equilibrium. Heart rate, left ventricular developed pressure (LVDP), left ventricular end-diastolic pressure (LVEDP), and the maximum rate of increase or decrease of left ventricular pressure (± dp/dt_max) were recorded. Infarct size was determined using triphenyltetrazolium chloride (TTC) staining. Myocardial TUNEL staining was used as the in situ cell death detection method and the percentage of TUNEL-positive nuclei to all nuclei counted was used as the apoptotic index. The expression of STAT3, bcl-2 and bax was determined by Western blotting. After reperfusion, compared to the I/R group, H₂S significantly improved functional recovery and decreased infarct size (23.3 ± 3.8 vs 41.2 ± 4.7%, P < 0.05) and apoptotic index (22.1 ± 3.6 vs 43.0 ± 4.8%, P < 0.05). However, H₂S-mediated protection was abolished by AG-490, the JAK2 inhibitor. In conclusion, H₂S postconditioning effectively protects isolated I/R rat hearts via activation of the JAK2/STAT3 signaling pathway.     

Bilateral receptive fields of cells in rat Sm1 cortex

Summary Single cells in the primary somatosensory (Sm1) cortex were investigated for responses to bilateral hindpaw stimulation in Wistar rats anaesthetised by continuous intravenous administration of Althesin. Fifty-one percent of cells sampled (N = 134) responded to equivalent punctate mechanical stimuli delivered to both the contralateral and ipsilateral hindpaws under light anaesthesia. The distribution by cortical depth of cells with receptive fields (RFs) on both hindpaws was not significantly different from cells which had only contralateral RFs. No cell was found with a purely ipsilateral RF. For 86% of cells tested (N=44) the ipsilateral RF was partly or completely homologous with areas within the contralateral RF. The sizes of ipsilateral RFs were smaller on 66% of occasions when tested against their contralateral RFs. Modal latencies to ipsilateral mechanical stimulation were longer than to contralateral stimulation (34.1±9.1 ms (S.D) cf. 26.4±7.2 ms, N=44). Ipsilateral RFs were lost for 77% of cells tested following a 33% increase in anaesthetic infusion rate. Conditioning mechanical stimuli applied to the centre receptive field (CRF) on the ipsilateral hindpaw reduced or abolished a cell's responses to equivalent test stimuli applied to it's contralateral CRF with C-T intervals of 20–200 ms. Conditioning stimuli applied to the CRF contralateral to the cell reduced or abolished responses to test stimuli on the cell's ipsilateral CRF using C-T intervals of 0–900 ms. Responses in one cortex to stimulation of the ipsilateral hindpaw were unaffected by elimination of responses from the same hindpaw in the opposite contralateral Sm1 cortex, where responses had been suppressed by topical Lignocaine administration. Retrograde transport of horseradish peroxidase from hindpaw Sm1 cortex labelled many cells in homolateral thalamus, but failed to label cells in the entire forebrain contralateral to the injection site. It is concluded that direct crossed thalamocortical and callosal Sm1-Sm1 pathways do not contribute to the production of hindpaw ipsilateral receptive fields.