Introduction of cremaster muscle chamber technique for long-term intravital microscopy

This study evaluated the microcirculatory hemodynamics of a new chamber implantation technique. The cremaster muscle island flap was employed. Seventeen male Sprague-Dawley rats were studied in two groups. In the control group, the standard cremaster muscle preparation with no chamber (N = 8) was used. After flap isolation, the muscle was preserved in the medial border of the hind limb and removed for observation after 24 hours. For the chamber group, the chamber was implanted after muscle isolation, and measurements were made 30 minutes postoperatively and at 24, 48, and 72 hours. The variables measured were microvessel diameter, red blood cell velocity, number of perfused capillaries, and the number of rolling, sticking, and transmigrating leukocytes in the postcapillary venules. The chamber group had a significantly greater number of perfused capillaries at 24 hours compared with controls (p < 0.05). The other variables did not differ significantly between groups at 24 hours. We can conclude that this cremaster muscle chamber model for chronic in vivo studies proved to be equal to the classic cremaster muscle preparation for chronic microcirculatory measurements for at least 24 hours.