目的:探究年轻化内环境是否可以改善老年小鼠肾缺血再灌注损伤(IRI)诱导的肾间质纤维化。方法:采用12周龄和22月龄雄性C57BL/6小鼠建立青年-青年、青年-老年和老年-老年联体共生模型3周后，应用受体小鼠、单体青年和老年小鼠构建单侧IRI(uIRI)模型。联体和单体模型小鼠分为青年-青年连体uIRI组(Y-IP uIRI组)、青年-老年连体uIRI组(O-HP uIRI组)、老年-老年连体uIRI组(O-IP uIRI组)、青年uIRI组(Y uIRI组)、老年uIRI组(O uIRI组)，共5组。分别于术后1 d、3 d和14 d采集血液和肾组织样本。检测小鼠血清肌酐和尿素氮等肾功能指标；天狼星红染色观察肾组织病理学变化；Western印迹检测α-平滑肌肌动蛋白、波形蛋白和I型胶原蛋白等纤维化标志物。结果:Y-IP uIRI组小鼠的肾功能14 d恢复至基线水平，而O-IP uIRI组和O-HP uIRI组的的肾功能未恢复。然而，O-HP uIRI组的肾功能较O-IP uIRI组明显改善。14 d时O-IP uIRI组和O-HP uIRI组的肾间质纤维化较Y-IP uIRI组明显增加。而且，O-HP组较O-IP uIRI组小鼠的肾间质纤维化明显减轻。Western印迹检测肾间质纤维化标志物α-平滑肌肌动蛋白、波形蛋白和I型胶原蛋白的蛋白表达亦出现相似变化。结论:年轻化内环境可以改善老年小鼠肾脏IRI诱导的肾间质纤维化，延缓其AKI-CKD进展。

健康寿命的调控机制逐渐成为衰老研究领域内最前沿的方向之一.近年来,一些新思路、新方法的出现为健康寿命调控机制研究注入了新的活力.比如,利用异种共生的方法阐明了循环系统如何影响衰老进程,为干预衰老提供了新思路;单细胞测序分析技术使科学家们能够从单细胞水平上解析组织器官、机体的衰老进程中基因表达的时空变化规律;多组学生物信息学分析技术助力了在长寿人群中发现与健康长寿相关的遗传元件、环境因素.这些新技术的运用为衰老研究带来了新的机遇.

联体共生(parabiosis)模型最早在1863年被制作成功,并在1972年首次将有年龄差别的该模型(heterochronic parabiosis)引入对于寿命的研究.近年来,该模型在衰老研究领域取得了不少进展,并在神经系统、肌组织、骨组织和胰腺组织等方面取得了一些有意义的结论.本文将2011年以来基于有年龄差别的该模型在衰老研究中的应用做一综述,总结该领域的研究进展,梳理潜在的药物靶点,归纳研究的热点和焦点问题,并对该领域今后的发展方向做一展望,试图探索出研究的新思路.

如何抑制衰老过程中器官系统功能的随增龄衰退,进而延缓衰老的进程,一直是衰老研究的难题.近年来的研究发现,通过手术,将年老动物与年轻动物的一侧前肢和后肢之间的皮肤缝合在一起,使它们之间形成血液循环系统的共通共享,可以有效逆转年老动物的多个器官的衰老表型,甚至能延长年老动物的寿命.进一步的研究发现,直接注射年轻动物血浆也能有效改善年老动物的衰老表型.这些结果提示,年轻血液中存在有改善衰老的因子.本文综述年轻血液延缓衰老的相关的研究进展.

Alzheimer's disease is the most common neurodegenerative disorder and no disease-modifying treatment is currently available. Research has shown that while brain neurogenesis continues in adult life, it declines with age. Using parabiosis, plasma transfusions and direct administration of neural growth factors, animal studies have demonstrated the positive impact of exposure to young blood products on neurogenesis and synaptic plasticity in an aging brain. The hippo-campus and the sub-ventricular zones were identified as the main regions affected. Promising findings have prompted researchers to experiment their effects in subjects with an established neurocognitive disorder, such as Alzheimer's disease. They argued that modification of brain vasculature, reactivation of adult neural stem cells, and remodeling of their synaptic activity/plas-ticity may lead to cognitive enhancement and increased neurogenesis. One pilot human study found that young donor plasma infusion protocols for adults with Alzheimer's disease were safe and feasible; however, no statistically significant improvements in cognition were detected. There is a need to conduct additional placebo-controlled human studies in larger samples. Future stud-ies should focus on identifying an "optimal age" at which an intervention in humans may yield significant cognitive enhancement, as well as determining the types of transfusions with the best efficacy and tolerability profiles.

In the human body,50-70 billion cells die every day,resulting in the generation of a large number of apoptotic bodies.However,the detailed biological role of apoptotic bodies in regulating tissue homeostasis remains unclear.In this study,we used Fasdeficient MRL/Ipr and Caspase 3-/-mice to show that reduction of apoptotic body formation significantly impaired the self-renewal and osteo-/adipo-genic differentiation of bone marrow mesenchymal stem cells (MSCs).Systemic infusion of exogenous apoptotic bodies rescued the MSC impairment and also ameliorated the osteopenia phenotype in MRL/Ipr,Caspase 3-/-and ovariectomized (OVX) mice.Mechanistically,we showed that MSCs were able to engulf apoptotic bodies via integrin avβ3 and reuse apoptotic body-derived ubiquitin ligase RNF146 and miR-328-3p to inhibit Axin1 and thereby activate the Wnt/β-catenin pathway.Moreover,we used a parabiosis mouse model to reveal that apoptotic bodies participated in the circulation to regulate distant MSCs.This study identifies a previously unknown role of apoptotic bodies in maintaining MSC and bone homeostasis in both physiological and pathological contexts and implies the potential use of apoptotic bodies to treat osteoporosis.

目的:通过异时连体共生(heterochronic parabiosis,HP)模型检测年轻小鼠血液循环环境对年老小鼠脊柱椎旁肌肉的影响.方法:选择4月龄的年轻小鼠及18月龄年老雌性小鼠,通过手术建立年轻和年老小鼠同时(isochronic parabiosis,IP)、异时连体共生模型.连体8周后将小鼠分成同时连体年轻小鼠组(young isochronic,YI),异时连体年轻小鼠组(young heterochronic,YH);同时连体年老小鼠(old isochronic,OI)和异时连体年老小鼠组(old heterochronic,OH)4组,解剖并提取椎旁肌肉.通过流式细胞仪吸光度检测各组椎旁肌肉糖胺聚糖(glycosaminoglycans,GAG)及各组DNA的含量,提取肌肉组织蛋白行蛋白印痕(Western blot)检测衰老基因P53、P21、P16及自噬基因LC3、金属蛋白酶MMP13基因的表达.取脊柱椎旁肌肉组织进行组织免疫荧光(immunofluorescence,IF)检测Aggrecan、P16及炎症因子IL8的表达差异性.结果:GAG定量分析显示YI、YH、OH、OI各组分别为2.91±0.17、2.01±0.21、2.23±0.36、1.18±0.09,其中YI与YH、OH与OI组之间有统计学差异(P＜0.05);通过IF检测Aggrecan表达呈下降趋势,YI、YH、OH、OI各组分别为717.25±64.44、611.59±28.45、683.04±17.95、570.34±31.81,其中OH与OI组间有统计学差异(P＜0.05),YI与YH组间无统计学意义(P＞0.05);LI8基因表达YI、YH、OH、OI各组分别为494.20±28.35、561.62±44.72、602.35±45.57、726.36±58.40;P16基因表达YI、YH、OH、OI各组分别为701.30±27.21、695.92±31.06、754.82±25.78、815.54±24.70,有上升趋势但YI与YH、OH与OI组间无明显差异(D0.05).Western blot检测自噬基因LC3Ⅱ/Ⅰ蛋白表达呈下降趋势YI、YH、OH、OI各组分别为0.39±0.09、0.29±0.05、0.26±0.04、0.16±0.01;衰老基因P21蛋白表达YI、YH、OH、OI各组分别为1.09±0.23、1.32±0.12、1.54±0.03、1.86±0.06;金属蛋白酶MMP13蛋白表达YI、YH、OH、OI组分别为0.59±0.11、0.68±0.13、0.88±0.15、1.11±0.18.在LC3Ⅱ/Ⅰ、P21、MMP13表达中,YI与YH组间无明显差异性(P＞0.05),OH与OI组间有统计学差异(P＜0.05).结论:全身血液循环可以影响椎旁肌肉退变,年轻血液环境可以延缓年老小鼠脊柱椎旁肌肉衰老退变.

目的:通过异时联体共生(heterochronic parabiosis)模型评估年老小鼠血液循环因素对年轻小鼠脊柱椎间盘衰老表型的影响.方法:本研究通过手术建立年轻和年老小鼠同时(isochronic parabiosis,IP)、异时联体共生模型.随机选择3个月龄的年轻及18个月龄年老雌性小鼠.联体8周后分成同时联体年轻小鼠组(young isochronic,Y-Y),异时联体年轻小鼠组(young heterochronic,Y-O),同时联体年老小鼠组(old isochronic,O-O).通过组织切片H&E染色观察椎间盘组织学改变,提取椎间盘组织行Western blot和RT-qPCR检测衰老基因P16、P21及金属蛋白酶MMP13、ADAMTS4蛋白和基因表达的差异性.取脊柱椎间盘组织进行组织免疫荧光检测aggrecan基因表达差异.结果:H&E染色结果显示Y-Y组椎间盘纤维环结构完整,纤维环及髓核组织没有裂痕,纤维环及髓核分界清楚,髓核组织含大量髓核细胞,基质完整;而Y-O组可见纤维环结构破损并出现裂痕,纤维环及髓核分界不清,髓核细胞数相比Y-Y组明显减少;O-O组表现为老年椎间盘形态特征.IF检测aggrecan基因表达量Y-Y组明显高于Y-O及O-O组,各组间表达有差异性(P<0.05).Western Blot检测P16蛋白表达Y-O组比Y-Y组升高77.1±20.5％(P<0.05),RT-qPCR检测P16基因Y-O组有升高的趋势,但组间无统计学差异(P>0.05);Western Blot检测P21蛋白Y-O组比Y-Y组有升高,但无明显统计学差异(P>0.05),但RT-qPCR检测P21基因Y-O组比Y-Y组升高40.5％±6.7％、O-O组比Y-Y组升高95.5％±24.2％(P<0.05);金属蛋白酶MMP13及ADAMTS4蛋白在Y-Y组表达明显低于Y-O及O-O组(P<0.05),RT-qPCR检测MMP13及ADAMTS4基因表达差异性与蛋白表达相符合.结论:老年小鼠血液循环因素可以加速年轻小鼠椎间盘衰老退变.

Parabiosis is a surgical method of animal modeling with a long history.It has been widely used in medical research,particularly in the fields of aging,stem cells,neuroscience,and immunity in the past two decades.The protocols for parabiosis have been improved many times and are now widely accepted.However,researchers need to consider many details,from surgical operation to perioperative management,to reduce mortality and maintain the parabiosis union.Although parabiosis has certain inevitable limitations,it still has broad application prospects as an irreplaceable animal model in the medical research field.