Erythrocyte Osmotic Fragility and Oxidative Stress in Experimental Hypothyroidism

Abstract

The present study was planned to explain the relation between erythrocyte osmotic fragility and oxidative stress and antioxidant statue in primary hypothyroid-induced experimental rats. Twenty-four Spraque Dawley type female rats were divided into two, as control (n = 12) and experimental (n = 12), groups weighing between 160 and 200 g. The experimental group animals have received tap water methimazole added standard fodder to block the iodine pumps for 30 d (75 mg/100 g). Control group animals were fed tap water and only standard fodder for the same period. At the end of 30 d blood samples were drawn from the abdominal aorta of the rats under ether anesthesia. T3, T4, and TSH levels were measured and the animals that had relatively lower T3, T4, and higher TSH levels were accepted as hypothyroid group. Hormone levels of the control group were at euthyroid conditions. Osmotic fragility, as a lipid peroxidation indicator malondialdehyde (MDA), antioxidant defense system indicators superoxide dismutase (SOD) and glutathione (GSH) levels were measured in the blood samples. Osmotic fragility test results: There was no statistically significant difference found between maximum osmotic hemolysis limit values of both group. Minimum osmotic hemolysis limit value of hypothyroid group was found to be higher than that of control group values (p < 0.02). The standard hemolysis and hemolytic increment curve of the hypothyroid group drawn according to osmotic fragility test results was found to be shifted to the right when compared to control group's curve. This situation and hemolytic increment value, which shows maximum hemolysis ratio, is the proof of increased osmotic fragility of the erythrocytes in hypothyroidism. There is no statistically significant difference found between hypothyroid and control groups in the lipid peroxidation indicator MDA and antioxidant indicators SOD and GSH levels. As a result of our study it may be concluded that hypothyroidism may lead to an increase in osmotic fragility of erythrocytes. But the increase in erythrocyte osmotic fragility does not originate from lipid peroxidation.

Regulation of oxidative stress and lipid peroxidation in PTU induced mice, treated with Pyrroloquinoline quinone (PQQ)

“…Some workers suggest that hypothyroidism protects tissues against accelerated lipid peroxidation, although the data concerning oxidation / antioxidation in hypothyroidism are incomplete and contradictory (Isman et al, 2003;Venditti and Di Meo, 2006). In fact, Dariyerli et al, (2004) did not find any change in the content of malondialdehyde in rats with thiamizoleinduced hypothyroidism. However, following PQQ administration there was a significant increase in its level in all studied tissues.…”

Effect of ascorbic acid administration on erythrocyte osmotic fragility of pigs transported by road during the hot-dry season

“…This increased erythrocyte osmotic fragility may be attributed to the concomitant effects of heat and road transportation stresses, which have been shown to cause increased generation of free radicals in animals (Nazifi et al 2009) and increased free radical generation has been demonstrated to result in oxidative stress (i.e. an impairment of equilibrium between pro-oxidants and antioxidants) (Dariyerli et al 2004;Chakraborti et al 2008;Halliwell 2009). The reason that, erythrocytes are highly susceptible to oxidative stress as a result of high amount of unsaturated fatty acid content in their membranes (Altan et al 2003) further supports the fact that free radicals generation in stress, would decrease the antioxidants in the body (Tauler et al 2003;Nazifi et al 2009).…”

Oxidative Stress and Antioxidant Status in Hypo- and Hyperthyroidism

“…Mano et al [15] found that the concentration of lipid peroxides, determined indirectly by the measurement of thiobarbituric acid reactants, did not change in hypothyroid rats when compared with the euthyroid animals. Dariyerli et al [227] showed that there is no statistically significant difference found between hypothyroid and control groups in the lipid peroxidation indicator MDA. The results of Yilmaz et al [228] who reported increased plasma, liver and muscle MDA levels in hypothyroid rats contradict our findings.…”