Exp Clin Endocrinol Diabetes 2008; 116 - N2
DOI: 10.1055/s-0028-1096329

A rat model of cerebral salt wasting

A Kleindienst 1, S Schlaffer 1, H Tam 2, JG Verbalis 2, M Buchfelder 1
  • 1Department of Neurosurgery, University of Erlangen-Nuremberg, Erlangen, Germany
  • 2Department of Endocrinology, Georgetown-University, Washington, D.C., USA

Purpose: Electrolyte disorders that result from acute brain damage as traumatic brain injury or subarachnoid hemorrhage (SAH) are yet not completely understood. One potential sequela, cerebral salt wasting (CSW), results often in severe hyponatremia, which to date has not been explained by alterations of peripheral hormone levels. Experimental and anatomical evidence suggests that hypothalamic dysfunction not only influences pituitary endocrine function, but also the peripheral sympathetic system via direct descending neuronal connections. Controlled clinical trials are difficult and potentially dangerous in this very ill population. Therefore, studies using an animal model that mimics the clinical features of CSW offer the best opportunity to understand the underlying pathophysiology. Methods: In male Wistar rats (325–350g), SAH was induced by injecting 200µl of autologous blood into the great cistern. The rats were housed in metabolic cages, and the daily sodium excretion as well as serum sodium, osmolality and vasopressin (AVP) were measured for 5 days. Results: Serum sodium (141.5mmol/l day 0, 142.0mmol/l day 5), osmolality (303.5 mosmol/kg day 0, 307.2 mosmol/kg day 5) remained stable, while the initial increase of AVP normalized over the investigation period (46.99 pg/ml day 0, 8.14 pg/ml day 5). Sodium excretion was increased on day 5 (0.74 mmol/day 3, 1.10 mmol/day5). Conclusion: In contrast to the existing literature, we could not confirm CSW as early as 12 hours following SAH in the rat. On day 5, natriuresis was increased but did not result in hyponatremia. We conclude that the rat model of SAH may be suitable for studying CSW when the observation extends the acute period.