快速老化小鼠P8肾脏衰老的病理特点
作者：施晓芸陈晓春石艳清杨明叶洪赵朝晖
【摘要】目的观察快速老化小鼠P8(SAMP8)肾脏病理结构改变。
方法以9月龄SAMP8为衰老动物模型，同龄抗快速老化小鼠R1(SAMR1)为对照，通过PAS、Masson染色及衰老相关β半乳糖苷酶 (SAβgal) 组织化学染色观察肾脏组织病理的改变，免疫组化方法比较肾小管间质细胞外基质 (ECM)成分——纤维连接蛋白 (FN)、Ⅲ型胶原(Col Ⅲ)的变化。
结果 9月龄SAMP8小鼠光镜下肾脏病理表现为小管间质纤维化、局灶节段性肾小球硬化等，以小管间质损害较为显著;SA βgal染色阳性细胞显著增加;免疫组化结果显示FN、ColⅢ在肾小管间质过度沉积。
上述改变与SAMR1组相比，差异有显著性。
结论SAMP8肾脏的病理改变符合肾脏衰老的特点。
【关键词】快速老化小鼠;衰老;肾脏
【Abstract】 Objective To study renal pathological structural changes in senescence accelerated mouse P8 (SAMP8). Methods SAMP8 (9 months) were used as senescence animal model and senescence accelerated mouse/resistance 1 (SAMR1) with same age as a control group. Aging kidney pathology was determined by several senescent indicators, such as PAS and Masson staining.
SAβgalactosidase activity was measured by histochemistry staining and extracellular matrix components (fibronectin and collagen Ⅲ) were measured by immunohistochemical staining. Results Compared with SAMR1 group, SAMP8 group appeared different levels of senescence. Renal pathological structural changes in SAMP8 (9 months), including tubulointerstitial fibrosis and focal segmental glomerulosclerosis, were found through microscope, and there was significant injury in the tubulointerstitial. Positive staining for SAβgalactosidase was widely observed. And the expressions of fibronectin and collagen Ⅲincreased remarkably which indicating tubulointerstitial fibrosis. Conclusions Renal pathological changes in SAMP8 mice accord with the pathological characteristic of aging kidney.
【Key words】 SAM; Senescence; Kidney
快速老化小鼠(senescence accelerated mouse，SAM)是目前人类衰老相关疾病研究领域广泛应用的动物模型，其特异性衰老相关的病理表型与许多人类老年性疾病的病理改变类似，且发生率及严重程度随年龄增长而增加，如亚系之一的SAMP8(SAM/prone 8)主要表现为学习记忆力障碍和低恐怖低紧张状态，故常应用于人类老年期痴呆的
研究。
肾脏是机体衰老过程中变化最为显著的器官之一，有关SAMP8肾脏的病理特点却鲜见报道。
本文将就SAMP8肾脏的病理结构作一初步研究。
1 材料与方法
1.1 实验动物以9月龄SAMP8为研究对象，同龄生命过程正常的SAMR1(SAM/resistance 1)为对照，每组各8只，均为雄性，体重30～40 g (购自北京大学医学部实验动物科学部)，SPF环境下饲养。
1.2 药品和试剂 X gal美国Sigma公司;兔抗小鼠纤维连接蛋白(FN)多克隆抗体美国LAB VISION公司;兔抗小鼠Ⅲ型胶原(Col Ⅲ)多克隆抗体武汉博士德生物工程有限公司。
1.3 组织标本收集和处理氯氨酮以70 mg/kg体重的剂量腹腔注射麻醉小鼠后，腹正中切开，原位灌洗，剥离双肾，取一侧肾脏置于新鲜配制的4%多聚甲醛溶液中固定24 h(置于4℃冰箱)，用于制备石蜡切片;另一侧肾脏分成数块，以OCT包埋，液氮冷冻后-80℃冻存，用于制备冰冻切片，进行衰老相关β半乳糖苷酶(SAβgal)的组织化学染色。
1.4 PAS染色和肾小管-间质损伤评分 PAS染色按常规方法操。