Objectives: 

The aim was to determine Zinc effect on the Erythraemia and RVH in hypobaric hypoxia and related genes expression.

Materials: 

Wistar rats were exposed to simulated hypoxia in a hypobaric chamber at 428 Torr (4800m) for 30 days, randomly allocated in 3 groups: Chronic (CH), n= 16; Intermittent (CIH), hypoxia 2 days/2 days normoxia; n= 16; Normoxia (NX; n= 16). Each group was divided into two (n= 8) receiving intraperitoneally, either a Zn sulphate solution at 1% or just saline, every 4 days. Gene expression in lung parenchyma of Metallothionine (Mt-1a), NOX4, eNOS, iNOS and HIF-1α, were evaluated by RT-PCR. Mt protein´s expression was assessed by Western Blot.

Results: 

Plasma Zinc levels decreased in all exposed groups, but less in Zn supplemented groups (p<0.001). All hypoxic groups showed RVH (p<0.05), being greater in Zn-CH group (p<0.05). Also, Htc-Hb increased in hypoxic groups, showing the largest increase in Zn-CH group (p<0.001). A correlation between RVH and Hb was found (r=0.76; r2 =0.58; p<0.001). An up-regulation of mRNA of NOX4, HIF1&#945; and Mt-1a, in all the exposed groups was observed (p<0.001), whereas in Zn administered groups were markedly greater (p<0.001). Also, an induction of eNOS and iNOS in the exposed groups was observed (p<0.001), without differences regarding Zn. A greater expression of Mt protein was only showed in Zn-CH, p<0.01.

Conclusions: 

Zinc supplementation enhances the development of erythrocytosis and RVH in rats exposed to hypoxia. Also, an up-regulation of genic expression of mRNA of NOX4, HIF1&#945;, MT and Mt protein is seen.

By Grant GORE-Tarapaca.