Dynamic viscoelasticity of the healing ligament treated by in vivo intermittent oxygen exposure in rats

The effects of intermittent exposure to hyporbaric oxygen (HBO) on experime ntally induced ligament tear were studied in the right hind limb of 10 male Wistar rats. Ten rats were divided into the following two groups of five: Group A, merely exposed to normobaric room air (control group); Group B, tr eated with HBO at 2 ATA 100% O-2 X 60 min X once/day (HBO group). The dynam ic stiffness and tan 6 of the injured patellar ligament were measured 4 wee ks after infliction with the original viscoelastic spectrometer. From our r esults, the stiffness of injured ligament did not recover from the average of control site at 4 weeks after injury, whether or not HBO was used (p < 0 .05). The tan delta of injured site at 11 Hz in the HBO group was higher th an that in control group (p < 0.05). This study suggests, from the point of elasticity, that the ligament of acc elerated collagen synthesis with HBO were still fragile at the time of 4 we eks after wounding. However, dynamic viscoelasticity was found to be not in fluenced enough by in vivo intermittent oxygen supply. (C) 2001 Elsevier Sc ience B.V. All rights reserved.