Effects of lead exposure to rat placenta and pups during different gestation periods / 中华预防医学杂志

<p><b>OBJECTIVE</b>To investigate the effects of lead exposure to rat placenta and pups during different gestation periods.</p><p><b>METHODS</b>All 108 Wistar rats (72 females, 36 males) were randomly divided into four groups. All rats were orally fed with 0.025% lead acetate during different gestation periods. Blood was obtained from the abdominal vena cava and the lead level in maternal blood was measured by means of atomic absorption spectrometry at the end of the pregnancy. The number of pups, their body weight, body length and tail length were measured. The effects of lead to rat placenta were observed by level of microscopy, optical microscopy and electronic microscopy.</p><p><b>RESULTS</b>Experimental groups the blood lead level at the end of gestation were above 0.483 micromol/L. There were significant differences among, of pups, during different groups (P < 0.01). Among them the drinking lead group of whole distant was the lowest in placenta weight [(0.31 +/- 0.13) g] body weight of pups [(2.08 +/- 0.88) g] length and tail length of pups [(2.37 +/- 0.32) cm, (0.98 +/- 0.09) cm]. There were significantly differences between the experimental groups and controls. Maternal blood lead level was negatively related to placenta weight (r = 0.652, P < 0.01), and had no relation with the body weight of pups (r = -0.107, P = 0.46). In the experimental groups of lead poisoned rats, the placenta showed focus necrosis in the deciduas, and increased the trophoblastic giant cells and light staining cells in the trophospongium. Trophoblast in the labyrinth and trophospongium showed degeneration; fibrin deposition around the villi was increased. Microvilli around the trophoblast were shorter and less, mitochondrion was swollen and decreased in number, rough endoplasmic reticulum was distended and ribosomal number on membrane decreased.</p><p><b>CONCLUSION</b>Lead exposure during different gestation periods should have a traumatic effect on the trophoblast, leading to interference of nutrition and oxygen exchange. Furthermore, the blood supply to the placenta and nutrition and oxygen exchange between mother and pups were also interfered, leading to reduction of placenta weight and retardation of development of pups.</p>

Correlation between Level of Nitric Oxide/Nitricoxide Synthase and Ultra-Structure Changes of Placenta Exposured in Lead Gestation Period in Rats / 实用儿科临床杂志

Objective To study the correlation between level of nitric oxide/ nitricoxide synthase(NO/NOS) on placenta homogenate and ultra-structure changes of placenta in pregnancy lead exposure in rats.Methods Seventeen normal pregnant rats and 46 rats of exposured in lead which were divided into A,B,C groups were studied.The level of NO/NOS of placenta were measured by nitrate reductase and NOS kit.Placentas were randomly selected from each group to detect ultra-structure by electron-microscope.Results There were significant difference among A,B and control groups on level of NO/NOS(all P0.05).Compensation hyperplasy or minor injury were observed in lead exposure of stage groups.Lead exposure during whole gestation period,the lead level was maxmum,and decompensation were observed on placental construction.Conclusions There is a close correlations between level of lead,NO/NOS and pathological change of placental tissue,and both of them may play an important role in the pathogenesis of peripartum lead exposure.