Effects of intrathecal morphine and fentanyl on IFN-γ levels in hippocampus and plasma of rats with incisional pain / 中华麻醉学杂志

ABSTRACT

Objective:To evaluate the effects of intrathecal morphine and fentanyl on interferon (IFN)-γ levels in hippocampus and plasma of rats with incisional pain.Methods:Ninety-six healthy male Sprague-Dawley rats in which intrathecal catheters were successfully inserted, weighing 180-220 g, aged 6-8 weeks, were divided into 4 groups ( n=24 each) using a random number table method: normal saline group (group NS), incisional pain group (group P), morphine and fentanyl group (group MF) and morphine and fentanyl with incisional pain group (group MFP). Incisional pain model was established in group P and group MFP.At 20 min before the model was established, a 50 μl mixture of morphine 5 μg/kg and fentanyl 0.25 μg/kg was intrathecally injected in group MF and group MFP, while normal saline 50 μl was injected intrathecally in group NS and group P. At 24 h before establishment of the model (T 0) and at 1, 6, 24, 48 and 72 h after establishment of the model (T 1-5), 6 mice were randomly selected from each group for determination of the mechanical paw withdrawal threshold (MWT) and thermal paw withdrawal latency (TWL). The animals were sacrificed and hippocampal tissues and blood samples from the inferior vena cava were collected for determination of IFN-γ levels in hippocampal tissues and plasma (by enzyme-linked immunosorbent assay). Results:Compared with group NS, MWT was significantly decreased and TWL was shortened at T 1-5, and IFN-γ concentration in plasma was decreased at T 2, 3 and T 5 in group P, MWT was increased and TWL was prolonged at T 1-3 in group MF, MWT was decreased and TWL was shortened at T 1-3 in group MFP, and IFN-γ concentration in plasma was decreased at T 2 in MF and MFP groups ( P<0.05). Compared with group P, MWT was increased, TWL was prolonged at T 1-5, and IFN-γ concentration in plasma was increased at T 2, 3 and T 5 in MF and MFP groups ( P<0.05). Compared with group MF, MWT was decreased and TWL was shortened at T 1-4, and IFN-γ concentration in plasma was increased at T 2 and T 3 in MFP ( P<0.05). There was no significant difference in IFN-γ concentration at each time point among the 4 groups ( P>0.05). Conclusion:Intrathecal morphine and fentanyl can increase plasma IFN-γ concentration, and improve peripheral immunosuppression.