Dynamics of proximal and distal transport of sodium in case of bilateral gonadectomy and the efficacy of hormonal replacement therapy

Abstract

Introduction. The characteristic feature of current trauma in Ukraine and in the world is the prevalence of highly energetic skeletal trauma which is followed by the appearance of combined and multiple injuries with the formation of multiorgan dysfunction and failure. Because of the increase of life duration, the high interest of current traumatology is the investigation process of trauma course in older people. Among them the high interest is given to females in postmenopausal period. The decrease of estrogen level causes very unfavorable ground for the trauma course. However, the influence of severe trauma on changes in proximal and distal transport of sodium in case of hypoestrogenic state is not fully investigated. There is no available data concerning the effectiveness of hormonal replacement therapy in this condition.

The goal of the study: is to investigate the influence of cranioskeletal injury on the dynamics of proximal and distal sodium transport in rats with bilateral ovariectomy in the period of late changes of traumatic disease and evaluate the effectiveness of hormonal replacement therapy.   

Materials and methods. Experiments were performed on 42 non-linear white female rats with the weight of 200-220 g. The model of hypoestrogenic state was performed via surgical removal of the ovaries. 1 month after the gonadectomy in rats skeletal trauma was performed. As a treatment option in one subgroup of rats with gonadectomy and cranioskeletal injury we performed hormonal replacement therapy. The control groups were formed by intact rats and osteoporotic rats 1 month after gonadectomy which were not injured. In control groups and after 1 and 2 months of posttraumatic period we were investigating the functional state of kidneys by performing the water upload method. Afterwards we performed the laboratory checkup of creatinine and sodium levels in serum and urine and additionally calculated the values of proximal and distal sodium transport.   

Results and its discussion. It was found that the level of proximal and distal sodium transport depends on the estrogen level, the decrease of its secretion leads to the decrease of sodium reabsorption in tubules and the increase in secretion. These changes were more prevalent in proximal tubules. In the course of trauma 1 month after posttraumatic period the value was decreasing in both research groups. However, in rats with gonadectomy the changes were much bigger and stayed at the same level until the 2^nd month of the experiment. In rats without gonadectomy these values were achieving the same levels as control group until 2^nd month. The use of combined hormonal replacement therapy caused the increase of proximal and distal sodium transport in comparison to the group without receiving treatment. The results that we got though was not achieving the level of rats without gonadectomy, but it showed the perspective for the use of combined hormonal replacement therapy in case of hypoestrogenic state for the decrease of renal dysfunction.     

Conclusions: Bilateral ovariectomy in female rats after 1 month shows the decrease of proximal and distal sodium levels comparing to rats with preserved gonads. The cranioskeletal injury that happened 1 month after bilateral ovariectomy causes the much bigger decrease of proximal and distal sodium transport comparing to rats with preserved gonads. The use of combined hormonal replacement therapy caused lower changes in proximal and distal sodium transport comparing to rats without this treatment.