The Effects of Sex Hormones on Liver Regeneration after Liver Trauma in Animal Model

Abstract

Background: The surgical management of liver injuries remains a great challenge for the traumatologists and general surgeons. We hypothesized that administration of 17 â-estradiol, a female sex hormone, improves hepatocellular healing after liver trauma.
Methods: In an experimental model, 60 rats were divided into six subgroups: A (male control), B (male and estradiol), C (castrated male and estradiol), D (female control), F (female and estradiol), and G (oopherectomized female). After inducing liver trauma, estradiol subgroups received 3 doses of intravenous 17 â-estradiol (1 mg/kg) every 8 hours. 2 weeks post trauma, animals were sacrificed and hepatocellular regeneration was measured with the help of stereologic parameters of regeneration. Hepatocellular healing was compared between previous left lobe samples and the new post-traumatic right lobe samples.
Results: Stereological parameters of rats receiving 17 b-estradiol after trauma was much better regarding mean angiogenesis point counting and volume density, compared with non-receiver groups after 2 weeks of trauma (P < 0.005). There was no significant difference for hepatocyte nucleus, hepatocyte point counting and volume density between estradiol receiver and non-receiver groups. In a comparison between subgroups, female sex had the same effect as giving estradiol. Oopherectomized female rats had more fibrogenesis but less angiogenesis (P < 0.005). Fibrogenesis was more in groups that were estradiol non-receiver (P < 0.005). In an explicit comparison of control females and males, estradiol infused males and females, and castrated male or oopherectomized female groups showed that stereological parameters of hepatocyte and hepatocyte nucleus were lower in female subgroups, but angiogenesis was better for female groups except for oopherectomized females.
Conclusions: This study did support the administration of exogenic female hormone as an approach to augment the angiogenesis as a good index of regeneration for traumatic liver in rats.