Dexmedetomidine attenuates spinal cord ischemia–reperfusion injury through both anti-inflammation and anti-apoptosis mechanisms in rabbits

Abstract Background Dexmedetomidine (Dex) can improve neuronal viability and protect the spinal cord from ischemia–reperfusion (I/R) injury, but the underlying mechanisms are not fully understood. This study investigated the effects of dexmedetomidine on the toll-like receptor 4 (TLR4)-mediated nuclear factor κB (NF-κB) inflammatory system and caspase-3 dependent apoptosis induced by spinal cord ischemia–reperfusion injury. Methods Twenty-four rabbits were divided into three groups: I/R, Dex (10 µg/kg/h prior to ischemia until reperfusion), and Sham. Abdominal aortic occlusion was carried out for 30 min in the I/R and Dex groups. Hindlimb motor function was assessed using the Tarlov scoring system for gait evaluation. Motor neuron survival and apoptosis in the ventral grey matter were assessed by haematoxylin–eosin staining and terminal deoxynucleotidyl transferase-mediated dUTP biotin nick end labelling staining. The expression and localisation of ionised calcium-binding adaptor molecule 1, TLR4, NF-κB and caspase-3 were assessed by immunoreactivity analysis. The levels of interleukin 1β and tumour necrosis factor α were assessed using enzyme-linked immunosorbent assays. Results Perioperative treatment with dexmedetomidine was associated with a significant preservation of locomotor function following spinal cord ischemia–reperfusion injury with increased neuronal survival in the spinal cord compared to control. In addition, dexmedetomidine suppressed microglial activation, inhibited the TLR4-mediated NF-κB signalling pathway, and inhibited the caspase-3 dependent apoptosis. Conclusions Dexmedetomidine confers neuroprotection against spinal cord ischemia–reperfusion injury through suppression of spinal cord inflammation and neuronal apoptosis. A reduction in microglial activation and inhibition of both the TLR4-mediated NF-κB signalling pathway and caspase-3 dependent apoptosis are implicated

Closed reduction and internal fixation versus total hip arthroplasty for displaced femoral neck fracture

【Abstract】Objective:To compare the clinical effects between closed reduction and internal fixation (CRIF) and total hip arthroplasty (THA) for displaced femoral neck fracture. Methods:In this prospective randomized study, 285 patients aged above 65 years with hip fractures (Garden III or IV) were included from January 2001 to December 2005. The cases were randomly allocated to either the CRIF group or THA group. Patients with pathological fractures (bone tumors or metabolic bone disease), preoperative avascular necrosis of the femoral head, osteoarthritis, rheumatoid arthritis, hemiplegia, long-term bed rest and complications affecting hip functions were excluded. Results:During the 5-year follow-up, CRIF group had significantly higher rates of complication in hip Chin J Traumatol 2014;17(2):63-68 Closed reduction and internal fixation versus total hip arthroplasty for displaced femoral neck fracture Cao Liehu, Wang Bin, Li Ming, Song Shaojun, Weng Weizong, Li Haihang, Su Jiacan* joint, general complication and reoperation than THA group (38.3% vs. 12.7%, P<0.01; 45.3% vs. 21.7%, P<0.01; 33.6% vs. 10.2%, P<0.05 respectively). There was no difference in mortality between the two groups. Postoperative function of the hip joint in THA group recovered favorably with higher Harris scores. Conclusion:For displaced fractures of the femoral neck in elderly patients, THA can achieve a lower rate of complication and reoperation, as well as better postoperative recovery of hip joint function compared with CRIF

A Comparative Study of Bioartificial Bone Tissue Poly-L-lactic Acid/Polycaprolactone and PLLA Scaffolds Applied in Bone Regeneration

Bioartificial bone tissue engineering is an increasingly popular technique to repair bone defect caused by injury or disease. This study aimed to investigate the feasibility of PLLA/PCL (poly-L-lactic acid/polycaprolactone) by a comparison study of PLLA/PCL and PLLA scaffolds applied in bone regeneration. Thirty healthy mature New Zealand rabbits on which 15 mm distal ulna defect model had been established were selected and then were divided into three groups randomly: group A (repaired with PLLA scaffold), group B (repaired with PLLA/PCL scaffold), and group C (no scaffold) to evaluate the bone-remodeling ability of the implants. Micro-CT examination revealed the prime bone regeneration ability of group B in three groups. Bone mineral density of surgical site in group B was higher than group A but lower than group C. Meanwhile, the bone regeneration in both groups A and B proceeded with signs of inflammation for the initial fast degradation of scaffolds. As a whole, PLLA/PCL scaffolds in vivo initially degrade fast and were better suited to repair bone defect than PLLA in New Zealand rabbits. Furthermore, for the low mineral density of new bone and rapid degradation of the scaffolds, more researches were necessary to optimize the composite for bone regeneration