Dose response of enoxaparin at the cremaster muscle flap microcirculation

The effects of different dosages of enoxaparin (Lovenox), a low molecular-weight heparin, on microcirculation were investigated. The cremaster muscle model for intravital microscopy was used. Four groups were studied: in group I (n = 6), the controls no agent was given; in group II (n = 6), enoxaparin (2 mg/kg s.c.), in group III, (n = 6), enoxaparin (4 mg/kg s.c.); and in group IV, (n = 6), exoxaparin (8 mg/kg s.c.). These agents were injected before muscle dissection. All animals were observed under intravital microscopy, and measurements of capillary density and red blood cell velocity were taken at 2, 3, 5, and 7 h following subcutaneous enoxaparin injection. Statistical analysis revealed that the capillary density significantly increased in group II and group III, respectively, (by 33% (P < 0.0001) and 25% (P < 0.01) when compared to group I at the fifth hour. Group IV was not significantly different from group I in capillary density. There was no significant difference in red blood cell velocity in any of the groups. Propensity for bleeding was not observed in any of the groups during the dissections and observation periods except in group IV. In conclusion subcutaneous administration of 2 mg/kg enoxaparin improves (by 33%) capillary density without any bleeding complications at the cremaster muscle flap microcirculation at the fifth hour following injection (P < 0.0001). (c) 2005 Wiley-Liss, Inc. Microsurgery 25:147-151, 2005.