RESUMO
Objectives: Laryngeal cartilage defects are a major problem that greatly impacts structural integrity and function. Cartilage repair is also a challenging issue. This study evaluated the efficacy of a collagen scaffold enveloped by amniotic membrane (AM/C) on laryngeal cartilage repair. Study Design: Experimental animal study. Methods: Fourteen Dutch rabbits were enrolled in the study. A 5 mm cartilage defect was created in the right and left thyroid lamina. The animals were divided into two groups randomly. Group 1 collagen scaffolds and group 2 AM/C were applied to the right side defects. Left side defects were not repaired, serving as control. Histologic evaluation was done 45 and 90 days following collagen and AM/C application with criteria of tissue and cell morphology, lacuna formation, vascularization, and inflammation. Results: Significant improvement in cartilage repair was observed in the AM/C side compared to the control side in all histologic criteria after 45 days (p<.05). After 90 days, cartilage repair improved in cell morphology, lacuna formation, and inflammation significantly (p<.05). Conclusion: The combination of amniotic membrane and collagen scaffolds provides a promising treatment modality for improving the repair of laryngeal cartilage defects. Level of Evidence: NA.
RESUMO
AIM: In two recent studies, we observed that a 30-min renal vein clamping caused formation of interstitial haemorrhagic congestion in ischaemic and ischaemic/reperfused kidney along with the development of severer acute kidney injury (AKI) than renal artery or pedicle clamping. It was suggested that the transmission of high arterial pressure into renal microvessels during vein occlusion probably causes the occurrence of interstitial haemorrhagic congestion that augments AKI. The present investigation aimed to evaluate this suggestion by reducing renal perfusion pressure (RPP) during renal venous occlusion. METHODS: Anaesthetized male Sprague-Dawley rats were divided into three groups (n = 8), which underwent a 2-h reperfusion period following 30-min bilateral renal venous clamping along with reduced RPP (VIR-rRPP group) or without reduced RPP (VIR group) and an equivalent period after sham-operation (Sham group). RESULTS: The VIR-rRPP group compared with VIR group had lower levels of kidney malondialdehyde and tissue damages as epithelial injuries of proximal tubule and thick ascending limb, vascular congestion, intratubular cast and oedema, along with the less reductions in renal blood flow, creatinine clearance, Na+ -reabsorption, K+ and urea excretion, urine osmolality and free-water reabsorption. Importantly, the formation of intensive interstitial haemorrhagic congestion in the VIR group was not observed in the VIR-rRPP group. CONCLUSION: These results indicate that the transmission of high arterial pressure into renal microvessels during venous occlusion leads to rupturing of their walls and the formation of interstitial haemorrhagic congestion, which has an augmenting impact on ischaemia/reperfusion-induced renal structural damages and haemodynamic, excretory and urine-concentrating dysfunctions.