Bio evf5

Starting three days before surgery, the rats were introduced to the testing environment daily to allow for acclimation. The rats were placed in the environment used for the mechanical and thermal tests for 30 min before the tests were performed. Before and 1, 3, 5, and 7 days after surgery, the plantar surface of both ipsilateral and contralateral hind paws was probed using electrical von Frey tips (BIO-EVF5, Bioseb, France) to measure the thresholds of mechanical touch sensitivity (von Frey test). The tip was gently applied upward onto the rat’s middle plantar surface and force was slowly exerted until the rats withdrew, flicked, or licked their paw. The reading of the largest force (in grams) was automatically recorded. Each rat was tested five times separated by 15-s intervals.
Hargreaves test was performed on preoperative day 1 and 1, 3, 5, and 7 days after surgery to evaluate thermal sensitivity using a Plantar Test Apparatus (Ugo Basile, Comerio, Italy). An infrared heat source (50 W) was adjusted so that naïve rats had withdrawal latencies of 9–12 s. The heat source was focused on the plantar surface of the ipsilateral and contralateral hind paw and the time taken to withdraw from the heat stimulus was recorded. Each hind paw was tested three times separated by intervals of 2 min.

Mechanical punctate stimuli were given with the standard rigid electronic von Frey filament (BIO‐EVF5, BioSeb; Figure 2b). The MPT was defined as the lowest intensity perceived as painful for participants. The assessors applied steady force, approximately at the rate of 25 g/s (Reitz et al., 2016 (link)), with the electronic von Frey filament over the testing sites. Participants were instructed to inform the assessor immediately upon painful sensation.

Behavioral tests were performed three times—baseline (before modeling), pre-intervention, and post-intervention. MWT and TWL were operated on the right hind paw as in the previous description (Bennett and Xie, 1988 (link)). The measurement was repeated three times with a 10-min interval between each measurement.
MWT: Measurement started when exploratory and grooming behaviors stopped, and the rats were motionless and relaxed. An electronic Von Frey instrument (BIO-EVF5; Bioseb, USA) was used, avoiding the metal grid, and the same position on the plantar surface of the hind paws was stimulated with the disposable measurement tip. The intensity of the applied force was adapted, recording the animal’s response (e.g., curling hind paws, licking hind paws) and the maximum value automatically was recorded by the system.
TWL: Using a thermal analgesia device (PL-200; Chengdu Techman Software Co., Ltd., China), the heat intensity was set to 50%, and the latency was cut off at 30 seconds to prevent skin damage. The infrared source beneath the plantar surface of the hind paws was put in the right position. The recording of the animal’s response and the time was taken automatically by the system.