Effect of prepubertal nutrition on cellular apoptosis and proliferation in at term placenta of Anglo‐Nubian goats

The aim of this study was to evaluate the effect of feed restriction with or without monensin supplementation, followed by a re‐feeding period on cellular apoptosis and proliferation in at term placenta of Anglo‐Nubian goats. To evaluate the induction of apoptosis through the intrinsic pathway, proteins Bax and Bcl‐2 were determinated. The apoptosis was related with the cell proliferation indices through Ki67 determination. The treatments were applied for 250 days and were (a) ad libitum feeding (control; n = 5); (b) restricted feeding at 70% of control (restricted; n = 7); and (c) restricted with monensin supplementation (monensin; n = 7). After treatments, all the animals were fed to support their requirements. After parturition, 27 placentas were gathered. The placental cellular structure was studied by high‐resolution light microscopy and transmission electron microscopy; the cellular proliferation was determined by Ki67 index, and Bax and Bcl‐2 proteins were localized by immunohistochemical analysis. Differences in cell proliferation through the Ki67 index were found in monensin group placentas. Monensin supplementation stimulated the placental cell proliferation reversing the effect of feed restriction during the peripuberal period. A significant increase of Bcl‐2 in placentas of restricted group was found, and it would provide a protective effect on the placental structure. A lack of the Bcl‐2 protective effect was observed in control and monensin group placentas, probably meaning that the observed apoptosis would be induced through the intrinsic signalling pathway. A balance between apoptosis and cell proliferation is necessary to maintain tissue homoeostasis during caprine placental development.     

大鼠抗Thy 1．1系膜增生性肾炎模型的实验研究

目的：探讨复制SD大鼠抗Thy1．1系膜增生性肾炎实验模型的方法．观察其临床病理特点和肾小球系膜区细胞增殖核抗原(PCNA)、凋亡调节基因Bcl-2的表达。方法：用SD大鼠胸腺细胞免疫新西兰白兔，制备兔抗大鼠胸腺细胞免疫血清(Anti-Thy1．1 serum,ATS)．再将ATS经尾静脉注射给SD大鼠，诱导其发生系膜增生性肾炎(MsPGN)。每日检测尿蛋白。用HE和PASM染色法观察肾小球系膜增生程度．用免疫组化LSAB法检测系膜区PCNA及Bcl-2的表达。结果：ATS效价可达1:3200；诱导大鼠MsPGN的ATS最适用量为：0．01mL／g体重；大鼠MsPGN的临床特点为大量蛋白尿；病理特点为肾小球系膜细胞增生；增生期系膜区PCNA、Bcl-2的表达增高。结论：用ATS可诱导典型的、稳定的大鼠MsPGN实验模型；免疫反应和细胞凋亡受抑制参与了肾小球系膜增生的发病机制。