Effects of regional seawater immersion on the pain behavior and secondary neuropathological change in the rats model of skin/muscle incision and retraction

Objective To evaluate the effects of regional seawater immersion on the pain behavior and its secondary neuropathological change in the rats model of skin/muscle incision and retraction (SMIR). Methods Forty-eight male SD rats were randomly assigned into 3 groups (16 each): the model control group (only to set up SMIR model, Group MC), normal saline immersion group (to set up SMIR model and the incision immersed with normal saline, Group NS), seawater immersion group (to set up SMIR model and the incision immersed with seawater, Group SW). Mechanical paw withdrawal threshold (MWT) was measured 1d before and 1d, 3d, 5d, 7d, 14d, 21d and 28d after operation, respectively. At 3d and 28d after the operation, 8 rats were randomly selected from each group, ipsilateral saphenous nerves were taken from 4 rats for HE staining, and dorsal root ganglion of ipsilateral L3/L4 were taken from another 4 rats for ultrastructural observation by electron microscopy. Results Compared with the other two groups, MWT values in