[Healing of osteochondral defects in canine knee with avocado/soybean unsaponifiables: a morphometric comparative analysis]. / Avokado/soya fasülyesinin sabunlasmayan ekstresi verilen köpeklerin dizlerinde osteokondral defekt iyilesmesi: Bir karsilastirmali morfometrik analiz.

OBJECTIVES: This study aims to determine the effects of avocado/soybean unsaponifiables (ASU) on healing in a canine osteochondral defect model. MATERIALS AND METHODS: Fourteen dogs were included in the study and randomly divided into two groups. Two osteochondral defects were produced in the lateral aspect of the trochlear groove of the knee joint. The treatment group (group 1; n=7) was given 300 mg ASU capsules every three days whereas the control group (group 2; n=7) was given a normal diet. Animals were then allowed to ambulate normally until euthanasia at 15 weeks. The knees were dissected and the trochlear grooves with defects were removed for pathological examination. The amount of regenerated tissue was determined quantitatively using image analysis and the tissue content was evaluated semi-quantitatively using Safranin-O and Masson trichrome histochemical stains. Transforming growth factor beta (TGF-beta) increase was evaluated semi-quantitatively with immunohistochemical staining methods. RESULTS: Morphometric analysis revealed a significantly more immature repair tissue in group 1 (p<0.002). Both collagen and chondral tissue content of the regenerated tissue were significantly increased in group 1 (p<0.002). Compared to that in group 2, cartilage tissue in group 1 showed a much more marked immunostaining reaction of TGF-beta. CONCLUSION: Avocado/soybean unsaponifiables treatment stimulates the healing of the osteochondral defects in canine knee possibly by increasing TGF-beta in the tissues.

[In which period of skeletal muscle ischemia-reperfusion injury is local hypothermia more effective?]. / Iskelet kasi iskemi-reperfüzyon hasarinin hangi evresinde lokal soguk uygulamasi daha etkilidir?

OBJECTIVES: We investigated the potential beneficial effects of local hypothermia applied during different periods of ischemia-reperfusion injury in a rat model. METHODS: An isolated gracilis muscle model of ischemia-reperfusion injury was used consisting of four groups, each with six rats. Ischemic injury was induced by clamping the femoral artery for six hours. Local hypothermia at 10 degrees C was applied during only ischemia (IH), during reperfusion (RH) for four hours, and during both ischemia and reperfusion (IRH). The control group remained untreated. After 24 hours of perfusion, the rats were sacrificed and the gracilis muscles were removed to determine muscle edema (wet-to-dry weight ratio), polymorphonuclear leukocytes (PMNL), and the percentage of necrosis. RESULTS: Compared to the control group (193.7 +/-38.9), the PMNL count was significantly lower in the IH, RH, and IRH groups (111.5+/-36.2, p<0.004; 82+/-18.6, p<0.002; 54.5+/-21.8, p<0.002, respectively). The only significant difference in the PMNL count was between the IH and IRH groups (p<0.004). In all the hypothermia groups, the percentage of necrosis was found significantly less than that of the control group (22.5+/-5.2% vs 11.7+/-5.2% in IH, p<0.004; 10.8+/-3.8% in RH, p<0.004; 6.7+/-2.6% in IRH, p<0.002).Similarly, muscle edema was significantly decreased in the study groups (control, 2.89+/-0.46 vs 2.01+/-0.26 in IH, p<0.001; 1.98+/-0.34 in RH, p<0.001; 1.97+/-043 in IRH, p<0.001). There were no significant differences between the three hypothermia groups with respect to the percentage of necrosis and muscle edema. CONCLUSION: Our results show that local hypothermia applied during ischemic and reperfusion periods is significantly effective in reducing ischemia-reperfusion injury.

Treatment with unsaponifiable extracts of avocado and soybean increases TGF-beta1 and TGF-beta2 levels in canine joint fluid.

Avocado and soya unsaponifiables (ASU) are plant extracts used as a slow-acting antiarthritic agent. ASU stimulate the synthesis of matrix components by chondrocytes, probably by increasing the production of transforming growth factor-beta (TGF-beta). TGF-beta is expressed by chondrocytes and osteoblasts and is present in cartilage matrix. This study investigates the effect of ASU treatment on the levels of two isoforms of TGFbeta, TGF-beta1 and TGF-beta2, in the knee joint fluid using a canine model. Twenty-four outbred dogs were divided into three groups. The control animals were given a normal diet, while the treated animals were given 300 mg ASU every three days or every day. Joint fluid samples were obtained prior to treatment, and at the end of every month (up to three months). TGF-beta1 and TGF-beta2 levels were measured using a quantitative sandwich enzyme immunoassay technique. ASU treatment caused an increase in TGF-beta1 and TGF-beta2 levels in the joint fluid when compared to controls. The different doses did not cause a significant difference in joint fluid TGF levels. TGF-beta1 levels in the treated animals reached maximum values at the end of the second month and then decreased after the third month, while TGF-beta2 levels showed a marginal increase during the first two months, followed by a marked increase at the end of the third month. In conclusion, ASU increased both TGF-beta1 and TGF-beta2 levels in knee joint fluid.

Effect of Mg2SO4 usage on spinal cord ischemia-reperfusion injury: electron microscopic and functional evaluation.

OBJECTIVES: To evaluate the effects of intravenous magnesium sulfate (Mg(2)SO(4)) administration on ischemia-reperfusion injury of the spinal cord. MATERIAL AND METHODS: Sixteen rabbits were randomly assigned to the control (group I, 8 rabbits) and the study group (group II, 8 rabbits). The abdominal aorta was clamped for a period of 30 min followed by a reperfusion period of 60 min. The animals in group II received 0.25 ml/kg/h Mg(2)SO(4) intravenous infusion (15% Mg(2)SO(4)) throughout this procedure. The animals were then observed for 24 h after which their neurological states were evaluated and tissue samples obtained from the spinal cord were examined with electron microscopy. RESULTS: Aortic pressure distal to the cross-clamp during the occlusion period was 9 +/- 3 mm Hg in group I and 19 +/- 6 mm Hg in group II. All animals in group I were paraplegic at the end of the study. In group II the neurological outcome of 1 animal was poor while the other 7 animals were neurologically in a good condition. Electron microscopic examinations of the spinal cord tissues of group I revealed severe injury but the ultrastructure was well preserved in group II. CONCLUSIONS: Intravenous Mg(2)SO(4) administration may have protective effects on the ischemia-reperfusion injury of the spinal cord. We propose that Mg(2)SO(4) may be an additional protective pharmacological agent in thoracal and thoracoabdominal aortic surgery.

Magnesium-enriched coronary sinus retroperfusion during acute coronary artery occlusion.

BACKGROUND: The protective effect of coronary sinus retroperfusion in cases of ischaemic myocardium is clearly known. It restores the blood flow to the ischaemic tissue, reduces the infarct size, and improves the left ventricular pump function. METHODS: In this study, we investigated the effects of coronary sinus retroperfusion with the addition of magnesium sulphate on myocardial haemodynamics. A total of sixteen animals were entered into the study and divided equally into four groups: group I, control group, left anterior descending (LAD) coronary artery occlusion only; group II, LAD artery occlusion and Mg SO infusion; group III, LAD occlusion and retrograde coronary sinus perfusion; and group IV, LAD occlusion, retrograde coronary sinus perfusion and Mg SO infusion.(4) (4) RESULTS: Haemodynamic measurements were obtained throughout the study, at baseline, during the first and third hour of occlusion, and in the second, fourth and sixth hour of reperfusion. Although, the cardiac index was decreased in all groups, in the second hour of reperfusion it was significantly higher in groups III and IV compared to the control group. In the second hour of reperfusion cardiac index values were 56 +/- 5 and 63 +/- 6 ml/kg per min in groups III and IV respectively (P < 0.05) and as time passed this incremental change in groups III and IV became more apparent. In the fourth hour of reperfusion, group II showed significantly higher values than the control group. Group IV had higher values compared to group III at the fourth and sixth hours post-reperfusion. In general there were significant differences between groups II, III and IV at four and six hours post-reperfusion. The first derivative of pressure measured over time-the dP/dt value-was higher in groups III and IV compared to the control group in the first hour of occlusion (being 1650 +/- 55 and 1700 +/- 35 in groups III and IV respectively, and 1420 +/- 45 in the control group) and these differences continued throughout the occlusion and the reperfusion periods (P < 0.05). Group IV had the highest left ventricular stroke work index (LVSWI) values compared to the other groups in various pulmonary capillary wedge pressure (PCWP) measurements (P < 0.05). It was 0.78 g.m/kg at the 20 mmHg PCWP. CONCLUSIONS: Magnesium, if administered in an antegrade direction had only a limited effect, whereas magnesium-enriched retrograde coronary sinus perfusions appeared to significantly protect the ischaemic myocardium against the hazardous effects of ischaemic reperfusion injury.