L-精氨酸对生长受限孕鼠胎盘胰岛素样生长因子-Ⅰ及其受体表达的影响

目的观察L-精氨酸对生长受限孕鼠胎盘胰岛素样生长因子-Ⅰ(IGF-Ⅰ)及其受体(IGF-IR)表达的影响,探讨L-精氨酸对生长受限孕鼠的作用机制。方法取健康SD系大鼠雌雄3:1合笼饲养,按妊娠顺序随机抽取孕鼠分为空白组、模型组、观察组(L-精氨酸组)各12只,模型组、观察组孕8 d至孕20 d采用被动吸烟造模,模型组孕鼠腹腔注射生理盐水,观察组孕鼠腹腔注射L-精氨酸液,孕21 d剖宫取胎,计数活胎数,测量活胎仔身长、体质量、头臀长及胎盘质量并制备胎盘标本,采用免疫组织化学法检测IGF-I及IGF-IR。结果模型组胎鼠体质量、头臀长、胎盘质量均低于空白组与观察组(P<0.05),而观察组胎鼠体质量、头臀长、胎盘质量与空白组比较无明显差别(P>0.05)。光镜下各组胎盘均见IGF-I免疫反应阳性,模型组IGF-I、IGF-IR均低于空白组与观察组(P<0.05),而观察组IGF-I、IGF-IR与空白组比较无明显差别(P>0.05)。结论L-精氨酸可能通过直接或间接促进IGF-I的合成和分泌,促进吸烟所致生长受限胎仔的生长发育。

Effect of L-arginine on the expression of insulin-like growth factor-and the receptor of placentas in rats with fetal growth restriction

Objective To study the mechanisms of L-arginine to fetal growth restriction(FGR)by observing insulin-like growth factor-Ⅰ(IGF-Ⅰ)and IGF-Ⅰreceptor(IGF-ⅠR) in placentas.Methods The females and the males SD rats were raised in the same cage by the proportion of three ratio one.Thirty-six pregnancy rats were randomly divided into three groups: control group,model group and observation group(L-arginine group),there were 12 rats in each group.Model group and observation group were exposed to smoke after pregnant 8 days to 20 days.Saline was injected to enterocoelia of rats in control group.L-arginine was injected to rats in observation group.On day of gestation,the pup rats were deliveed by cesarean section.The live pup rats number were counted,and their body length,the body quality,the buttocks length and the placental weight were measured,and the placental specimens were prepared.IGF-I and IGF-IR were detected by immunohistochemical method.Results The body weight,buttocks length and placental weight in model group were lower than these in control group and observation group(P<0.05),but there were no difference in these indexes between control group and observation group(P>0.05).The expression of IGF-Ⅰand IGF-ⅠR in placentas of model group was lower than these in observation group and control group(P<0.05),but these were no obvious difference in the expression of IGFⅠand IGF-ⅠR between observation group and control group(P>0.05).Conclusion The L-arginine possibly promote the weight and the development of rats with FGR induced by passive smoking by directly(or indirectly) increasing the synthesis and secretion of IGF-I.