Effect of zinc supplementation on type 2 diabetes parameters and liver metallothionein expressions in Wistar rats

School of Republic Health, Jilin University, Changchun, People's Republic of China, 130021, .
Journal of physiology and biochemistry (Impact Factor: 1.97). 05/2012; 68(4). DOI: 10.1007/s13105-012-0174-y
Source: PubMed


Zinc is a trace metal and acts as an active component of various enzymes. Zinc deficiency has been suggested to be associated with the development of diabetes. The present study investigated the role of zinc supplementation on prevention of diabetic conditions. A double-disease model mimicking hyperlipidemia and type 2 diabetes was created by applying high-fat diet and streptozotocin (STZ) to Wistar rats. We demonstrated that zinc supplementation improved symptoms of diabetes such as polydipsia and increased serum level of high-density lipoprotein cholesterol, indicating that zinc supplementation has a potential beneficial effect on diabetic conditions. The level of maldondialdehyde (MDA), an oxidative stress marker, was reduced in liver by zinc supplementation in high fat-fed rats with or without STZ injection. Meanwhile, we observed an increase in the expression of metallothioneins (MTs) in liver of rats treated with zinc. This suggests that the induction of MTs in liver, which has been shown to be important in scavenging free radicals, could be one of the underlying mechanisms of zinc supplementation on reducing MDA levels in liver. Finally, we found that zinc levels in liver were increased while there was no change in serum zinc levels, indicating that local zinc level might be a critical factor for the induction of MTs. Also, the level of MTs could potentially be an index of zinc bioavailability. Taken together, these results suggest that both zinc and MT could play an important role in balancing nutrition and metabolism to prevent diabetic development.

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    • "The substantial increase in metallothionein in the affected sheep brain coincides with increased metal concentrations in this study. Because zinc-mediated up-regulation of metallothioneins [56] is suggested to be a protective measure against cellular damage it is possible that the increase in metal concentration and metallothionein are linked and serve as an attempt at cellular repair in the affected sheep brain. The fact that the levels of ceruloplasmin, another metal carrier protein implicated in iron homeostasis, correlate with neurological dysfunction in patients with CLN3 disease [57] suggests that metal-binding proteins may play an important role in NCLs. "
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