Intravenous Microinjections of Zebrafish Larvae to Study Acute Kidney Injury

In this video article we describe a zebrafish model of AKI using gentamicin as the nephrotoxicant. The technique consists of intravenous microinjections on 2 dpf zebrafish. This technique represents an efficient and rapid method to deliver soluble substances into the bloodstream of zebrafish larvae, allowing for the injection of 15-20 fish per hour. In addition to AKI studies, this microinjection technique can also be used for other types of experimental studies such as angiography. We provide a detailed protocol of the technique from equipment required to visual measures of decreased kidney function. In addition, we also demonstrate the process of fixation, whole mount immunohistochemistry with a kidney tubule marker, plastic embedding and sectioning of the larval zebrafish. We demonstrate that zebrafish larvae injected with gentamicin show morphological features consistent with AKI: edema, loss of cell polarity in proximal tubular epithelial cells, and morphological disruption of the tubule.     

自噬在肝再生中的作用

自噬是存在于真核细胞内的一种溶酶体依赖性的降解途径,在肝脏生理和病理过程中发挥着重要作用。肝脏具有强大的再生能力,在受到急、慢性损伤时,残肝细胞将会被激活进入细胞周期进行细胞增殖,以补偿丢失的肝组织和恢复肝功能。文章阐述了各种类型损伤之后的肝再生与自噬的关系。在物理性、酒精、食源性等因素引起的肝损伤中,肝脏通过启动自噬来促进肝再生;在化学性损伤的肝再生模型中,自噬在其中的作用仍然有争议;在病毒感染之后的肝再生中,一些嗜肝病毒（如丙肝病毒和乙肝病毒等）反而利用自噬来促进病毒颗粒复制,抑制肝再生。对自噬和肝再生机制的研究,将有助于进一步阐明再生过程,为治疗肝脏疾病提供新方法。     

Stem cells for spine surgery

In the past few years, stem cells have become the focus of research by regenerative medicine professionals and tissue engineers. Embryonic stem cells, although capable of differentiating into cell lineages of all three germ layers, are limited in their utilization due to ethical issues. In contrast, the autologous harvest and subsequent transplantation of adult stem cells from bone marrow, adipose tissue or blood have been experimentally utilized in the treatment of a wide variety of diseases ranging from myocardial infarction to Alzheimer’s disease. The physiologic consequences of stem cell transplantation and its impact on functional recovery have been studied in countless animal models and select clinical trials. Unfortunately, the bench to bedside translation of this research has been slow. Nonetheless, stem cell therapy has received the attention of spinal surgeons due to its potential benefits in the treatment of neural damage, muscle trauma, disk degeneration and its potential contribution to bone fusion.     

人脐带间充质干细胞微囊减轻小鼠急性肾损伤的研究

目的探讨人脐带间充质干细胞（MSCs）源性细胞外囊泡Oct-4 mRNA对受损的肾小管上皮细胞修复的作用及相关机制。 方法将培养的缺氧损伤肾小管上皮细胞置于含有人脐带MSCs细胞外囊泡及不同对照培养液的培养腔室玻片上孵育48?h,应用BrdU及TUNEL染色,检测各组细胞增殖或凋亡情况。将急性肾损伤模型小鼠分为4组：空白组、EVs组、Oct-4过表达组、Oct-4低敲组。并按照分组分别注射磷酸盐缓冲液（Vehicle）,人脐带MSCs细胞外囊泡（EVs）,过表达Oct-4基因的人脐带MSCs细胞外囊泡（EVs?+?Oct-4）及敲除Oct-4基因的人脐带MSCs外囊泡（EVs-Oct-4）,并在注射48?h及2周后采血测肌酐（Crea）及尿素氮（BUN）,了解肾功能变化;对各组上述处理后的肾组织应用TUNEL与增殖细胞核抗原表达量检测各组肾脏细胞凋亡与增殖情况;通过Masson染色检测了各组肾脏纤维化程度;通过PCR探索肾损伤后肾组织细胞Snail基因的表达变化。数据分析采用方差分析和SNK-q检验。 结果EVs?+ Oct-4处理缺氧的肾小管上皮细胞48?h后,TUNEL染色显示具有最少的凋亡细胞数（0~1）/?HPF,BrdU显示有最多的增殖细胞（7±2）/HPF。EVs,EV-Oct-4以及Vehicle对体外缺氧肾小管上皮细胞的上述作用依次减弱（P?相似文献   

间充质干细胞治疗急性放射性损伤的研究

急性放射性损伤是组织损伤的一种重要类型,目前未有较理想的治疗方案。间充质干细胞（MSCs）能够多向分化、自我更新,且具有分泌多种细胞因子、抗炎、免疫调节等生物活性。其在促进组织修复的优势显而易见,而移植的时机、剂量长期以来莫衷一是。致瘤性等安全问题制约其临床研究的进一步开展。近年来,MSCs趋向于无细胞化移植取得了明显成效。这一研究新进展势必迎来急性放射性损伤治疗的新格局,本文对此研究现状及进展进行综述。     

Association of a reactive intermediate derived from 1′,6‐dihydroxy metabolite with benzbromarone‐induced hepatotoxicity

Treatment with benzbromarone can be associated with liver injury, but the detailed mechanism remains unknown. Our recent studies demonstrated that benzbromarone was metabolized to 1′,6‐dihydroxybenzbromarone and followed by formation of reactive intermediates that were trapped by glutathione, suggesting that the reactive intermediates may be responsible for the liver injury. The aim of this study was to clarify whether the reactive intermediates derived from 1′,6‐dihydroxybenzbromarone is a risk factor of liver injury in mice. An incubation study using mouse liver microsomes showed that the rates of formation of 1′,6‐dihydroxybenzbromarone from benzbromarone were increased by pretreatment with dexamethasone. Levels of a hepatic glutathione adduct derived from 1′,6‐dihydroxybenzbromarone were increased by pretreatment with dexamethasone. Furthermore, plasma alanine amino transferase activities were increased in mice treated with benzbromarone after pretreatment with dexamethasone. The results suggest that the reactive intermediate derived from 1′,6‐dihydroxybenzbromarone may be associated with liver injury.     

The effect of antioxidant supplementation on bacterial translocation after intestinal ischemia and reperfusion

The intestine is highly sensitive to ischemia/reperfusion (I/R) injury. Intestinal I/R may cause local tissue injury and disruption of the intestinal mucosal barrier, allowing the passage of viable bacteria and endotoxins from the gastrointestinal lumen to distant organs. This phenomenon, known as bacterial translocation (BT), may lead to systemic disorders with high morbidity and mortality. Oxidative stress mediators such as reactive oxygen species, polymorphonuclear neutrophils and nitric oxide are believed to contribute to the intestinal I/R injury. Many antioxidants have shown protective effects against I/R injury of various organs. The present article provides an overview of studies investigating the effect of antioxidant supplementation on BT after intestinal I/R.     

810nm弱激光照射对大鼠急性脊髓损伤后巨噬细胞极化的作用研究

本研究构建急性大鼠脊髓夹伤模型,并将大鼠随机分为单纯脊髓损伤对照组及脊髓损伤联合弱激光照射组。照射组应用810 nm波长,150 m W照射功率,照射光斑0.3 cm^2的弱激光对脊髓损伤区进行经皮照射,连续照射3天,7天或14天。应用免疫荧光、免疫印迹实验方法,测定脊髓损伤区巨噬细胞及小胶质细胞的极化表达。应用酶联免疫吸附法测定脊髓损伤区白细胞介素4的表达情况。应用坚牢蓝髓鞘染色测定两组损伤脊髓中髓鞘保留的差异。采用BBB评分对两组大鼠后肢运动功能的恢复进行评估。结果表明,810 nm弱激光对脊髓损伤区连续照射3天,7天后,可显著减少M1型巨噬细胞及其标志物诱导型一氧化氮合酶的表达,在7天时间增加M2型巨噬细胞及其标志物精氨酸酶1的表达。弱激光照射组白细胞介素4的表达明显增加。损伤后14天,弱激光照射组脊髓损伤区髓鞘保留面积比值明显提高。损伤后7天及14天时,弱激光照射组大鼠的BBB评分明显升高。该实验结果表明,810 nm弱激光经皮照射,可增加大鼠急性脊髓损伤区M2型巨噬细胞及小胶质细胞的表达,并减少脊髓损伤后的髓鞘脱失,促进脊髓损伤大鼠运动功能的恢复。     

Regeneration of excised shell by the invasive apple snail Pomacea canaliculata

After excision of shell from Pomacea canaliculata, survival rates, repair process, haemocyte response, and calcium content were observed and quantified for three weeks. The following experimental treatments were used: black-colored individuals with large (BL-group) or small (BS-group) shell heights, yellow-colored individuals with large (YL-group) or small (YS-group) shell heights. The survival rates in BL-, YL-, BS-, and YS-groups after making partial excisions of snail shells were, respectively, 93.59, 94.87, 92.31, and 96.15%. Freshly regenerated shell could be seen at 1 day among the four groups after induction of shell regeneration. Regeneration shell filled the wound after 5–10 days. The area of regenerated shell in yellow-colored individuals was larger than that of black-colored individuals, but the thickness of regenerated shell was not significantly different. Multiple (four times) inductions of shell regeneration significantly enhanced the thickness of newly formed shells. Two types of circulating haemocytes (hyalinocytes and granulocytes) were identified under light microscopy based on Wright’s staining. Artificial induction of shell regeneration rendered a significant increase in the number of total circulating haemocytes which was followed by a decrease to pre-wounding levels. This peak value of total circulating haemocytes was 2.86, 2.43, 1.69, and 1.71-fold higher than pre-wounding levels in group BL, YL, BS, and YS, respectively. The number of total circulating haemocytes in yellow-colored individuals was significantly higher than in black-colored. Calcium concentrations in the mantles of snails are favorable for calcium nucleation. It is postulated that calcium content increased in the mantle increase at the start of the experiment and then returned to pre-wounding levels at the end of the experiment. This study shows that apple snails have effective shell regeneration abilities and that haemocytes and calcium transportation appear to play an important role in shell growth and regeneration.     

A multi-body dynamics study on a weight-drop test of rat brain injury

Traumatic brain injury (TBI), induced by impact of an object with the head, is a major health problem worldwide. Rats are a well-established animal analogue for study of TBI and the weight-drop impact-acceleration (WDIA) method is a well-established model in rats for creating diffuse TBI, the most common form of TBI seen in humans. However, little is known of the biomechanics of the WDIA method and, to address this, we have developed a four-degrees-of-freedom multi-body mass-spring-damper model for the WDIA test in rats. An analytical expression of the maximum skull acceleration, one of the important head injury predictor, was derived and it shows that the maximum skull acceleration is proportional to the impact velocity but independent of the impactor mass. Furthermore, a dimensional analysis disclosed that the maximum force on the brain and maximum relative displacement between brain and skull are also linearly proportional to impact velocity. Additionally, the effects of the impactor mass were examined through a parametric study from the developed multi-body dynamics model. It was found that increasing impactor mass increased these two brain injury predictors.