Bat 10

Male Sprague–Dawley rats, weighing 280 to 320 g, 7–8 weeks old, were provided by the Animal Center of Jinling Hospital, Nanjing, China. All rats were housed in controlled room on a 12-h light–dark cycle and fed a standard laboratory diet. This study was approved by the Ethics Committee of Jinling Hospital and was performed in accordance with the guidelines for the use of experimental animals by the National Institutes of Health. For experiments, animals were fasted overnight except for free access to water. Animals were anesthetized with intraperitoneal injection of 2% sodium pentobarbital (50 mg/kg) and intubated tracheally with a 14-gauge cannula. Polyethylene catheters were inserted into the left femoral artery and vein and flushed intermittently with saline solution which containing 2.5 IU/ml bovine heparin. The arterial catheter line was connected to a pressure transducer (PT-100, Chengdu Taimeng Software Co.LTD, China) to measure mean aortic pressure (MAP) and the venous catheter was used for medical administration, and the electrocardiogram was recorded by subcutaneous needle electrodes. Core temperature was monitored by a rectal temperature probe (BAT-10, Physitemp Instruments Inc) throughout the experiment to ensure appropriate temperature management.

Intraperitoneal hyperthermia was induced by i.p. administration of 2 + 2 mL saline solution preheated in water bath to 43 °C and separated by 5 min [9 (link)]. Hyperthermia treatment (HT) was performed immediately before the i.p. application of CP. CP was administered intraperitoneally at dose of 5 or 10 mg kg⁻¹. Systemic body temperature was determined before and during hyperthermia procedure using an electronic thermometer (BAT-10, Physitemp Instruments, Clifton, NJ, USA) with a rectal probe (RET-3, Physitemp Instruments, Clifton, NJ, USA). Intraperitoneal temperature was measured by the needle probe that was introduced to a depth of 1 cm into peritoneal cavity of mice treated with hyperthermia. Hyperthermia with applied procedure was well tolerated by the animals.
It is important to emphasize that during the heating phase, the intra-abdominal temperature was stable, ranging from 42.5–43 °C, whereas rectal temperature was not significantly affected. During the cooling phase, the temperature in the peritoneal cavity of treated mice decreased to normal values approximately 15 min after applying the hyperthermal procedure [11 (link),19 (link)].