Development of an animal model for chronic mild hyperhomocysteinemia and its response to oxidative damage

Abstract

The purpose of this study was to develop a chronic chemically induced model of mild hyperhomocysteinemia in adult rats. We produced levels of Hcy in the blood (30μM), comparable to those considered a risk factor for the development of neurological and cardiovascular diseases, by injecting homocysteine subcutaneously (0.03μmol/g of body weight) twice a day, from the 30th to the 60th postpartum day. Controls received saline in the same volumes. Using this model, we evaluated the effect of chronic administration of homocysteine on redox status in the blood and cerebral cortex of adult rats. Reactive oxygen species and thiobarbituric acid reactive substances were significantly increased in the plasma and cerebral cortex, while nitrite levels were reduced in the cerebral cortex, but not in the plasma, of rats subjected to chronic mild hyperhomocysteinemia. Homocysteine was also seen to disrupt enzymatic and non-enzymatic antioxidant defenses in the blood and cerebral cortex of rats. Since experimental animal models are useful for understanding the pathophysiology of human diseases, the present model of mild hyperhomocysteinemia may be useful for the investigation of additional mechanisms involved in tissue alterations caused by homocysteine.

Mild hyperhomocysteinemia alters extracellular adenine metabolism in rat brain

“…Plasma Hcy concentration in rats subjected to this treatment achieved levels similar to those described in the plasma of patients with mild hyperhomocysteinemia (30 lM) (Scherer et al, 2011). The animals were killed by decapitation 12 h after the last injection of Hcy and the cerebral cortex and CSF were removed.…”

“…Ectonucleotidases are integral membrane proteins (Yegutkin, 2008), therefore, it is plausible to suggest that the oxidative damage in membrane lipids may alter the normal function of these enzymes. Indeed, previous study from our group showed that mild hyperhomocysteinemia increases thiobarbituric acid reactive substances (TBARS) levels, an index of lipid peroxidation (Halliwell, 2006), in cerebral cortex in rats (Scherer et al, 2011). Other study demonstrated that Hcy in vitro decreases ATP and ADP hydrolysis in rat platelets probably by oxidative stress since antioxidants prevented such effects (Zanin et al, 2010).…”

“…We previously developed an experimental model of chronic mild hyperhomocysteinemia in adult rats (Scherer et al, 2011) and showed that this model was able to induce a decrease in extracellular nucleotide hydrolysis and ecto-5 0 -nucleotidase/CD73 gene expression pattern in rat lymphocytes (Scherer et 2012). Therefore, in this study we sought to investigate the effect of chronic mild hyperhomocysteinemia on ectonucleotidase activities and gene expression in rat cerebral cortex.…”

Effect of homocysteine on intestinal permeability in rats with experimental colitis, and its mechanism

“…DL-Hcy was dissolved in 0.9% normal saline and the pH value was adjusted to 7.4. According to the dosage previously reported [9], subcutaneous injection of Hcy (0.03 umol/g) was carried out twice per day with an 8-hour interval, from the first day after the establishment of TNBS/ethanol-induced colitis model. Hcy injection was continued at this rate for 30 days.…”

Homocysteine Promotes Intestinal Fibrosis in Rats with Trinitrobenzene Sulfonic Acid-Induced Colitis

“…DL-Hcy (SigmaAldrich Chemical Co., USA) was dissolved in 0.9 % normal saline and the pH value was adjusted to 7.4. Subcutaneous injection of Hcy (0.03 lmol g -1 ) was conducted twice per day with an 8-h interval from the first day after TNBS/ethanol administration through the end of thirty-day study [16]. The rats were randomly divided into 4 groups: …”