Yoruk Mecit, Kanter Mehmet, Meral Ismail, Agaoglu Zahid
Histoloji-Embriyoloji Anabilim Dali, Yuzuncu Yil Universitesi, Kampus, Van, Turkey.
Biol Trace Elem Res. 2003 Winter;96(1-3):217-26. doi: 10.1385/BTER:96:1-3:217.
This study was designed to investigate the effects of Cd exposure on the glycogen localization in the placenta and in fetal and maternal livers in streptozotocin (STZ)-induced-diabetic pregnant rats. Ninety-nine virgin female Wistar rats (200-220 g) were mated with 33 males for at least 12 h. From the onset of pregnancy, the rats were divided into four experimental groups (control, Cd treated, STZ treated, and Cd+STZ treated). The Cd-treated group was injected subcutaneously daily with CdCl2 dissolved in isotonic NaCl, starting at the onset of pregnancy throughout the experiment. Diabetes was induced on d 13 of pregnancy by a single intraperitoneal injection of STZ in the STZ-treated group. In addition to the daily injection of Cd, a single intraperitoneal injection of STZ was also given on d 13 of pregnancy in the Cd+STZ-treated group. The rats received the last injection 24 h before being sacrificed and 10 randomly selected rats in each group were sacrificed on d 15 and d 20 of pregnancy. Blood samples were taken for determination of the serum glucose and insulin levels. Fetal and maternal livers of sacrificed rats in all groups were harvested on d 15 and d 20 of pregnancy, whereas placentas were harvested only on d 20 of pregnancy for histochemical examination. Although both Cd and STZ caused hyperglycemia and decreased insulin secretion, Cd-alone treatment increased the glycogen content only in the placental labyrinth, whereas STZ-alone treatment increased the glycogen content only in the maternal part of the placenta. Increased glycogen localization was observed in both the placental labyrinth and the maternal part of placenta when Cd and STZ were given together. Fetal and maternal livers of control and other treatment groups were not different regarding the glycogen content on d 15 or d 20 of pregnancy. It was concluded that Cd exposure during pregnancy might produce a glycogen localization in the placenta of diabetic rats. However, the function and the mechanisms of increased glycogen contents in the placenta of Cd-exposed pregnant diabetic rats remain unclear and further studies are needed.
本研究旨在探讨镉暴露对链脲佐菌素（STZ）诱导的糖尿病妊娠大鼠胎盘以及胎儿和母体肝脏中糖原定位的影响。将99只处女雌性Wistar大鼠（体重200 - 220克）与33只雄性大鼠交配至少12小时。从怀孕开始，将大鼠分为四个实验组（对照组、镉处理组、STZ处理组和镉 + STZ处理组）。镉处理组从怀孕开始至整个实验期间每天皮下注射溶解于等渗氯化钠中的CdCl₂。STZ处理组在怀孕第13天通过单次腹腔注射STZ诱导糖尿病。镉 + STZ处理组除每天注射镉外，在怀孕第13天也单次腹腔注射STZ。大鼠在处死前24小时接受最后一次注射，每组随机选取10只大鼠在怀孕第15天和第20天处死。采集血样测定血清葡萄糖和胰岛素水平。所有组处死大鼠的胎儿和母体肝脏在怀孕第15天和第20天采集，而胎盘仅在怀孕第20天采集用于组织化学检查。虽然镉和STZ均导致血糖升高和胰岛素分泌减少，但单独镉处理仅增加胎盘迷路中的糖原含量，而单独STZ处理仅增加胎盘母体部分的糖原含量。当镉和STZ同时给予时，在胎盘迷路和胎盘母体部分均观察到糖原定位增加。对照组和其他处理组的胎儿和母体肝脏在怀孕第15天或第20天的糖原含量无差异。得出的结论是，孕期镉暴露可能导致糖尿病大鼠胎盘出现糖原定位。然而，镉暴露的妊娠糖尿病大鼠胎盘中糖原含量增加的功能和机制仍不清楚，需要进一步研究。
