| Background and objective: Iron is one of indispensable elements in human bodies, but taking too much will lead to iron accumulation in some substantial organs and induce abnormal oxidative stress and blood lipid metabolish of tissues,resulting in a series of pathological changes or damages. The purpose of this work is to study the long-term effect of excess iron supplementation on iron accumulation and functions of the organs of the offspring in rats,to explore possible mechanisms of the damages.Methods: Twenty-four 4-week-old Wistar rats(female : male = 2:1) were randomly divided into 4 groups: normal group(NC), low-doze iron overload group(LI), medium-doze iron overload group(MI), high-doze iron overload group(HI). Iron concentration in foodstuff were 50、150、450 and 1350 mg / kg, respectively. After a 12-week elapse, these rats began to mate. The same foodstuff and group were adopted for the offspring rats during the 14 weeks since their birth and the number of every group was adjusted to 10. Chloral hydrate in 10% was injected into abdomen of rats(0.5 ml / 100 g) for anesthesia after the end of final feeding, then bled from aorta abdominalis and cryopresrvated in – 80 ℃surroundings after separation.Detected the content of serum iron(SI),triglyeride(TG), total cholesterol(TC), low-density lipoprotein cholesterol(LDL-C) and high-density lipoprotein cholesterol(HDL-C) in serum, and also detected the liver function indexes of alanine transaminase(ALT), aspertate aminotransferase(AST) and alkaline phosphatase(ALP),detected the kidney function indexes of urea nitrogen(BUN), creatinine(CREA).At the same time, many important indexes of livers, kidneys and brains after separating them from the bodies were measured and recorded: total superoxide dismutase(T-SOD),glutathion peroxidase(GSH-PH), malondialdehyde(MDA), of tissues of livers, kidneys and brains.Results: After 14-week feeding, the analysis of iron accumulation levels in visceral organs indicated that, the iron content in liver tissues in NC group was 248.61 ug / g, and that in the LI, MI, HI groups were 1.50, 1.87 and 2.20 times(all P < 0.05), respectively. Comparing to the iron content(169.78 ug / g) in kidneys in NC group, the iron content in HI group increased 8.99%(P <0.05). The iron content in brains in NC group was 68.72 ug / g and these in LI, MI, HI groups were 1.50, 1.90 and 1.95 times(all P < 0.05). The levels of oxidative stress of visceral organs indicated that, the MDA contents in liver tissues of LI,MI, HI groups were 1.36, 1.56 and 1.51 nmol / mg prot respectively and they were 2.06, 2.36 and 2.29 times than that in NC group(0.66 nmol / mg prot)(all P < 0.05). GSH-PX activityin liver in MI group was 159.22 and increased 11.8% than that in NC group(142.41)(P <0.05). MDA contents in kidney tissues in LI, MI and HI groups were 1.95, 1.86 and 2.05 nmol / mg prot respectively, increasing 25.80%, 20.00% and 32.26% than that in NC group(1.55 nmol / mg prot)(all P < 0.05). GSH-PX activity in kidneys in LI and HI group were193.69 and 196.17 respectively, increasing 9.39% and 10.79% than that in NC group.MDA contents in brain tissues in LI, MI and HI groups were 4.41, 5.05 and 4.40 nmol / mg prot respectively, increasing 35.69%, 55.38% and 35.38% than that in NC group(all P <0.05); GSH-PX activity in brains in MI group were 1.39, increasing 44.79% than that in NC group(0.96)(P < 0.05). The level of liver function indicated that, the ALT content in liver tissues in NC group was 42.20U/L, and that in the LI, MI, HI groups were 1.23, 1.58and1.74 times(all P < 0.05), respectively. Comparing to the AST content(67.60U/L) in livers in NC group, the AST content in LI, MI, and HI group increased 28.70%,66.14% and 73.22%( all P <0.05). The ALP content in liver tissues in NC group was 76.20U/L, and that in the LI, MI, HI groups were 1.17, 1.17 and 1.27 times( all P < 0.05), respectively. The level of kidney function indicated that, the BUN content in kidney tissues in NC group was6.55mmol/L, and that in the LI, MI, HI groups were 1.14, 1.25 and 1.30 times(all P < 0.05),respectively. The CREA contents in kidney of MI and HI group increased 10.84% and27.10% than that in NC group(73.80μmol/L)(all P < 0.05).The level of blood lipid metabolism indicated that, TG content in LI, MI and HI groups increased 33.3%, 50.0%and 62.5% in comparison with that in NC group(0.24 mm mol / L)(all P < 0.05); TC content were 1.49, 1.55 and 1.55 mm mol / L respectively in LI, MI and HI group increasing12.9%, 17.42% and 17.42% than that in NC group(1.32 mm mol / L). The LDL-C content in LI, MI and HI groups were 0.41, 0.51 and 0.45 mm mol / L respectively, that were 2.05,2.55 and 2.25 times than that in NC group(0.20 mm mol / L)(all P < 0.05). However, The HDL-C contents in MI and HI decreased 13.50% and 9.00% than that in NC group(1.09 mm mol / L)(all P < 0.05), respectively.Conclusions: Long-term and excess iron supplementation could elevate the iron contents and lift the levels of oxidative stress remarkably in liver, kidney and brain, damage liver and kidney functions and lead to disorder of blood lipid metabolism in offspring rats. |
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