Rat Model Of Hindlimb Ischemia Research Articles

Microvessel development following therapeutic angiogenesis with vascular endothelial growth factor (VEGF) in a rat model of Hindlimb ischemia

Microvessel development following therapeutic angiogenesis with vascular endothelial growth factor (VEGF) in a rat model of Hindlimb ischemia

Use of synchrotron radiation microangiography to assess development of small collateral arteries in a rat model of hindlimb ischemia.

Current methods of angiography cannot provide images of arteries measuring < 200 microns in diameter. We have recently developed a new angiography system that uses monochromatic synchrotron radiation and a high-definition video system with a spatial resolution of 30 microns. In the present study, we applied this microangiography system to visualize small arteries in normal and ischemic rat limbs and investigated the development of collateral arteries. Microangiography was performed in the normal and the ischemic limb 4 weeks after the excision of the femoral artery. In the normal limb, up to the fourth branches of the iliac and/or femoral arteries (diameter < 100 microns) were readily identified. Some of these branches were found to perfuse the distal thigh area. In the ischemic limb, an extensive structural remodeling of the vascular network was observed. Numerous small arteries had developed from the branches of the iliac artery to constitute a fine arterial network, the so-called "midzone," which was composed of linear, normal appearing arteries and those with an undulating, unbranched appearance. The small collateral artery network was angiographically visualized with a resolution limit < 100 microns. The linear collaterals appeared to result from an opening of preexisting vessels. The undulating, unbranched vessels were not observed in the normal limbs and seemed to be vessels that were newly formed after limb ischemia. Synchrotron radiation microangiography appears to be a powerful means of assessing the development of small collateral arteries, which may help to provide a basis for understanding of the collateral circulation.

P-44 - Protective effects of TA-993,a novel therapeutic agent for peripheral circulatory insufficiency, on skeletal muscle fatigue in a rat model of hindlimb ischemia

P-44 - Protective effects of TA-993,a novel therapeutic agent for peripheral circulatory insufficiency, on skeletal muscle fatigue in a rat model of hindlimb ischemia

The role of leukocytes in the pathophysiology of skeletal muscle ischemic injury

Neutrophilic leukocytes have been implicated as important mediators of ischemic myocardial injury. We investigated the role of neutrophils in skeletal muscle ischemia/reperfusion injury by using the rat hindlimb ischemia model. We rendered Wistar rats neutropenic by administering 750 rad of whole-body radiation (mean white blood cell count, 300 +/- 50/mm3; 3 days after radiation). In anesthetized rats (10 neutropenic and 10 control), 3 hours of ischemia were induced in one hindlimb by application of a tourniquet to the proximal thigh; the contralateral limb served as an internal, nonischemic control. After 1 hour of reperfusion the gastrocnemius and soleus muscles were excised bilaterally and evaluated for ischemic injury by means of a quantitative spectrophotometric assay of triphenyltetrazolium chloride (TTC) reduction. In control rats the reduction of TTC by ischemic muscle averaged 27.0% +/- 7.3% of that by nonischemic muscle; whereas in neutropenic rats the value for ischemic muscle was 65.4 +/- 11.6% (p less than 0.05). To determine if the contribution of the neutrophils to ischemic injury is due to oxygen-derived free radical formation, an additional 10 animals were infused with 5000 units of super-oxide dismutase and 10,000 units of catalase at the time reperfusion was restored. After treatment with free radical scavengers, TTC reduction by ischemic limbs was 25.5% +/- 7.0% of that by nonischemic limbs and did not differ from that in control animals (p greater than 0.05). The results show a protective effect of neutropenia and suggest a significant role of the white cell in the pathophysiology of ischemic skeletal muscle injury.

The role of leukocytes in the pathophysiology of skeletal muscle ischemic injury

Neutrophilic leukocytes have been implicated as important mediators of ischemic myocardial injury. We investigated the role of neutrophils in skeletal muscle ischemia/reperfusion injury by using the rat hindlimb ischemia model. We rendered Wistar rats neutropenic by administering 750 rad of whole-body radiation (mean white blood cell count, 300 ± 50/mm3; 3 days after radiation). In anesthetized rats (10 neutropenic and 10 control), 3 hours of ischemia were induced in one hindlimb by application of a tourniquet to the proximal thigh; the contralateral limb served as an internal, nonischemic control. After 1 hour of reperfusion the gastrocnemius and soleus muscles were excised bilaterally and evaluated for ischemic injury by means of a quantitative spectrophotometric assay of triphenyltetrazolium chloride (TTC) reduction. In control rats the reduction of TTC by ischemic muscle averaged 27.0% ± 7.3% of that by nonischemic muscle; whereas in neutropenic rats the value for ischemic muscle was 65.4 ± 11.6% (p < 0.05). To determine if the contribution of the neutrophils to ischemic injury is due to oxygen-derived free radical formation, an additional 10 animals were infused with 5000 units of superoxide dismutase and 10,000 units of catalase at the time reperfusion was restored. After treatment with free radical scavengers, TTC reduction by ischemic limbs was 25.5% ± 7.0% of that by nonischemic limbs and did not differ from that in control animals (p > 0.05). The results show a protective effect of neutropenia and suggest a significant role of the white cell in the pathophysiology of ischemic skeletal muscle injury.

Effect of superoxide dismutase plus catalase on Ca 2+ transport in ischemic and reperfused skeletal muscle

Cytotoxic oxygen metabolites may contribute to skeletal muscle damage associated with ischemia and reperfusion. This study utilized a rat hindlimb ischemia model to investigate the effect of pretreatment with oxygen free radical scavengers superoxide dismutase (SOD) and catalase (CAT) on skeletal muscle Ca 2+ uptake by sarcoplasmic reticulum (SR) in limbs subjected to periods of ischemia and reperfusion. SOD and CAT were conjugated to polyethylene glycol to prolong their half lives. Anesthetized rats (ca. 350 g) received an iv injection of either conjugated SOD (2 mg/kg) plus CAT (3.5 mg/kg) ( n = 6, Treated Group) or 0.9 saline (4 ml/kg) ( n = 6, Control Group) 5 min before unilateral hindlimb tourniquet ischemia of 3 hr duration. After 19 hr of reperfusion, muscle from each lower leg was excised and homogenized. Skeletal muscle SR was isolated by differential centrifugation. ATP-dependent Ca 2+ uptake by the SR was then measured with dual wavelength spectrophotometry and used as an index of muscle function. Pretreatment with SOD and CAT maintained higher rates of Ca 2+ uptake by SR of skeletal muscle from postischemic reperfused limbs (Treated Group 2.29 ± 0.21 vs Control Group, 1.61 ± 0.06 μmole Ca 2+/mg protein/min). These results implicate cytotoxic oxygen metabolites in the pathogenesis of ischemic reperfusion skeletal muscle injury.