Different groups of rats received an intradermal injection of vehicle (control) or HMWH (1 μg) on the dorsum of the hind paw. 10 min later, hyaluronidase (5U, left panel) or LMWH (1 μg, right panel) was injected at the same site. Comparison of the mechanical thresholds before and 30 min after the injection of hyaluronidase or LMWH showed intense mechanical hyperalgesia in both groups. However, in the groups pretreated with HMWH it was significantly attenuated (left panel: t5 = 7.214, *** p = 0.0008; right panel:
t5 = 4.130, ** p = 0.0091, when HMWH-treated and the control groups are compared), indicating an anti-hyperalgesic effect of the HMWH. (Student's t test ; n = 6 paws per group)