Effect of chronic treatments with GH, melatonin, estrogens, and phytoestrogens on oxidative stress parameters in liver from aged female rats

Abstract

The aging theory postulates that this process may be due to the accumulation of oxidative damage in cells and molecules. The present study has investigated the effect of castration in old female rats on various parameters related to the antioxidant properties of several cellular fractions obtained from the liver, and the influence of several chronic treatments on it, both in intact and castrated animals. Sixty-one 22-month-old Wistar female rats, were used. About 21 intact animals were divided into three groups and treated for 10 weeks with GH, melatonin or saline, and 40 ovariectomized (at 12 months of age) animals were divided into five groups and treated for the same time with GH, melatonin, estrogens (Eos), phytoestrogens (Phyt) or saline. All animals were sacrificed at 24 months of age by decapitation. The activity of glutathione peroxidase (GPx) in cytosolic fraction, glutathione-S-transferase (GST) in cytosol and microsomal fractions, and the levels of nitric oxide (NO) and cytochrome C in mitochondrial and cytosol fractions of liver were determined. A decrease in GST activity was detected in cytosol and in the microsomal fraction in ovariectomized animals as compared to intact rats. The activity of GPx was also decreased in ovariectomized as compared with the intact group. NO level was increased and cytochrome C decreased in the mitochondrial fraction of the liver in ovariectomized females as compared with the intact group, respectively. No significant changes after melatonin or GH treatments were found in GPx, GST activity and NO level in mitochondrial fraction in the intact group. Administration of GH, melatonin, Eos and Phyt in the ovariectomized groups significantly increased the GPx, and GST activity in the cytosol and microsomal fraction and decreased the level of NO in the mitochondrial fraction as compared with the untreated rats. A significant increase in the level of cytochrome C in the mitochondrial fraction and a decrease in the cytosol fraction were also found with all treatments. The administration of GH, melatonin, Eos and Phyt to castrated females seem to reduce oxidative changes in the liver from old ovariectomized rats.

Relationship between Oxidative Stress and Cardiomyopathic Changes in Ovariectomized Rats

“…It has also been described that the alteration in GSH concentration caused by ovariectomy is accompanied by increased LPO, with elevated production of malondialdehyde [42]. Our results are consistent with the majority of studies, which have reported an increase in LPO and a decrease in GSH after ovariectomy [42,45]. …”

Is reproduction costly? No increase of oxidative damage in breeding bank voles

“…It has been shown that ovariectomized rats produce significantly more peroxide than control females, and this effect disappears after estrogen supplementation (Borras et al, 2003). Estradiol supplementation to ovariectomized females has been shown to significantly increase the activity of glutathione peroxidase and the concentration of glutathione (Borras et al, 2003;Kireev et al, 2007). Most importantly, suppression of the ROS generating system by estrogens has been shown to result in lower lipid peroxidation in various tissues in rats (Huh et al, 1994;Persky et al, 2000).…”

Age-related changes in the activity and expression of manganese superoxide dismutase, and mitochondrial oxidant generation in female and male rats

“…Accordingly, the previous studies carried out in rats have reported that females had lower oxidative stress and mitochondrial dysfunction than the males [29][30][31]. However, these reports concerning the gender differences in mitochondrial oxidant status have either dealt with the 4-6 months old animals [32][33], or applied some interventions such as ovariectomy and estrogen replacement therapy [30,32,34,35].…”