Effects of hydrogen-rich saline on incisional pain-remifentanil-induced hyperalgesia in rats / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the effects of hydrogen-rich saline on incisional pain-remifentanil-induced hyperalgesia in rats.Methods Thirty-two male Sprague-Dawley rats,aged 2-3 months,weighing 240-260 g,in which the catheter was successfully inserted into the caudal vein,were randomly divided into 4 groups (n =8 each) using a random number tablecontrol gourp (group C),remifentanil + incisional pain group (group R + I) and different doses of hydrogen-rich saline groups (H1 and H2 groups).A l-cm longitudinal incision was made through skin,fascia and muscle of the plantar aspect of the left hindpaw in chloral hydrate-anesthetized rats.Remifentanil 1 μg· kg-1 · min-1 was infused intravenously for 60 min sarting from beginning of establishment of incisional pain model in R + I,H1 and H2 groups.The equal volume of normal saline was infused intravenóusly for 60 rin instead of remifentanil group C.Hydrogen-rich saline 5 and 10 ml/kg were injected intraperitoneally at 10 min before establishment of incisional pain model in H1 and H2 groups,respectively.Paw withdrawal threshold (PWT) to yon Frey hair stimulation and paw withdrawal latency (PWL) to thermal stimulation were measured at 24 h before remifentanil infusion and 2,6,24 and 48 h after remifentanil infusion (T0-T4).The rats were sacrificed after measuremnt of pain threshold,and L4-6 segments of the spinal cord were removed for determination of the expression of R1 and 2B subunits-containing N-methyl-D-aspartate receptors (NR1 and NR2B) in total and membrane proteins by Western blot.The ratio between the expression of NR1 in membrane protein and in total protein (mNR1/tNR1) and NR2B in membrane protein and in total protein (mNR2B/tNR2B) was calculated.Results Compared with group C,PWT was significantly decreased,PWL was shortened,the expression of mNR1,mNR2B,tNR1 and tNR2B was up-regulated,and the ratios of mNR1/tNR1 and mNR2B/tNR2B were increased in R + I,H1 and H2 groups.Compared with group R + I,PWT was significantly increased,PWL was prolonged,the expression of mNR1 and mNR2B was down-regulated,and the ratios of mNR1/tNR1 and mNR2B/tNR2B were decreased in Ht and H2 groups.Compared with group H1,PWT was significantly increased,PWL was prolonged,the expression of mNR1 and mNR2B was down-regulated,and the ratios of mNR1/tNR1 and mNR2B/tNR2B were decreased in group H2.Conclusion Hydrogen-rich saline can attenuate incisional pain-remifentanil-induced hyperalgesia in rats and inhibition of trafficking of spinal neuronal NR1 and NR2B from cytoplasm to cell membrane may be involved in the mechanism.