Protection of estrogen in portal hypertension gastropathy: an experimental model

Abstract

-Context -Portal hypertension is a complication secondary to cirrhosis that is characterized by increased blood flow and/or vascular resistance in the portal system, causing the appearance of a hyperdynamic collateral circulation. Partial portal vein ligation is an experimental model used in rats to study the pathophysiological mechanisms involved in pre-hepatic portal hypertension. Estrogen E2 is an antioxidant molecule with various physiological actions. Objectives -To evaluate the antioxidant activity of endogenous estrogen in an experimental model of partial portal vein ligation by comparing intact with castrated rats. Methods -Twenty Wistar rats, weighing on average 250 g were used and divided into four groups: sham-operated (SO); intact (I) with partial portal vein ligation (I + PPVL), castrated (C) and castrated with partial ligation of the vein (C + PPVL). Day 1: castration or sham-operation; day 7, PPVL surgery; on day 15 post-PPVL, portal pressure in the mesenteric vein of rats was measured on polygraph Letica. Lipid peroxidation in the stomach was assessed using the technique of thiobarbituric acid reactive substances and activity of antioxidant enzymes superoxide dismutase, catalase and glutathione peroxidase. Statistical analysis was done with ANOVA -Student-NewmanKeuls (mean ± SE), and P<0.05 was considered as significant. Results -Portal pressure was significantly increased in C + PPVL as compared to the other groups. There was no significant difference in the group of intact rats. TBARS showed significant damage in C and C + PPVL in relation to others. Antioxidant enzymes were significantly increased in the castrated rats with subsequent PPVL as compared to the other groups. Conclusion -We suggest that estrogen E2 plays a protective role in intact compared with castrated rats because it presents hydrophenolic radicals in its molecule, thus acting as an antioxidant in this experimental model.

Effect of experimentally induced portal hypertension on the fundic mucosa of adult male albino rats and the possible protective role of quercetin supplementation

“…Moreover, it can provide measurements in the portal circulation [29] that cannot be performed accurately in humans because of ethical and technical limitations [30]. In the current study, portal pressure in the PPVL group was significantly increased in comparison with the control group.…”

“…PPVL is an experimental model used in rats to study the histopathological mechanisms involved in prehepatic PHT with a maintained liver integrity and a hyperdynamic circulation that develops in a short and predicted period 1 week after induction [29]. Moreover, it can provide measurements in the portal circulation [29] that cannot be performed accurately in humans because of ethical and technical limitations [30].…”

Estrogen derivatives

“…Experimental studies have shown that E 2 reduced portal pressure and increased hepatic blood flow in castrated and cirrhotic model rats, but the effect was significantly inhibited by ICI-182780 [62,81]. E 2 played a protective role by acting as an antioxidant, because the hemodynamic changes involved in PHT led to increased ROS, which triggered oxidative stress [82].…”

“…E 2 played a protective role by acting as an antioxidant, because the hemodynamic changes involved in PHT led to increased ROS, which triggered oxidative stress [82]. In castrated rats, a significant increase in the activity of antioxidant enzymes and lipid peroxidase was observed, which might occur to compensate for the absence of circulating E 2 , promoted by castration, but even then it was not effective in reducing lipid peroxidase [81,83,84]. Estrogen replacement could reverse this effect, reverting to the values of the control animals [84].…”

Constriction rate variation produced by partial ligation of the portal vein at pre-hepatic portal hypertension induced in rats

“…In the portal hypertension dilation of the splanchnic veins occurs, and collateral circulation is developed. This situation may happen with diseases in pre, intra or post-hepatics stages 10 . Thrombosis of the portal vein or splenic vein triggers pre-hepatic portal hypertension.…”