Survival of rats undergoing continuous bile drainage depends on maintenance of circadian rhythm of bile secretion

It is very difficult to collect bile secretions from animals: for extended periods,of time. We compared the use of saline or water as drinking fluids to sustain the animals, which were being continuously drained of bile. Comp lete bile drainage was performed in 16 male Wistar rats by surgical interve ntion. After surgery, 8 rats were given tap water, and the other 8 were giv en normal saline for water. The rats that received water rapidly lost weigh t after bile drainage, and all died within 8 days after the operation. In c ontrast, all rats that drank saline maintained their body weight and surviv ed 14 days or longer after surgery. Serum biochemistry of the rats with wat er intake on the third day after bile drainage revealed hyponatremia, hypoc hloremia, and acute renal failure resulting in hyperkalemia. In contrast, e lectrolyte balance and renal function were normal in the rats with saline i ntake, and bile was secreted continuously with a circadian rhythm. These re sults clearly demonstrate that saline as drinking water is essential to the replacement of lost fluids and loss of electrolytes due to bile drainage,F urther, saline proved efficacious for sustaining experimental animals under going continuous bile collection.