Effects of strawberry leaf and celery seed extracts in terlipressin-induced chronic hyponatremia in rats

Hyponatremia (HN) is associated with mortality and morbidity risks due to development of encephalopathy and neurogenic pulmonary edema. Moreover, its rapid correction carries a high risk of development of the serious cerebral disorder known as osmotic demyelination syndrome (ODS). In the present study, chronic HN was induced in rats using a single daily administration of terlipressin (TP), a synthetic, long-acting analogue of vasopressin, for 3 days. TP-induced HN was then used to study the possible therapeutic effects of strawberry leaf extract (StrwLE) and celery seed extract (CelrSE), and to compare their effects with that resulting from rapid correction using hypertonic saline (HtNaCl). Serum sodium level, as a marker of HN, was measured following induction and treatment, respectively. The study was extended to investigate changes in locomotor activity, pain reşex and lung function using an activity cage, hot-plate test, and spirometer, respectively. Furthermore, assessment of brain nitric oxide (NO) content, that has been shown to play a role in the pathogenesis of ODS, was carried out. It was found that TP induced a profound (<115 mmo/l) chronic (>48 h) HN that was coupled by decreased locomotor activity, delayed pain reşex and impaired lung function. Administration of StrwLE resulted in a correction of HN with its subsequent neurological dysfunction without elevation of the brain content of NO; however, it resulted in deterioration of the lung function parameters of hyponatremic rats. These findings suggested that StrwLE is useful for treatment of chronic HN, yet, further investigations are required to study its effect on the lungs.