No abstract

Extreme/direct lateral interbody fusion (X/DLIF) has been used to treat various lumbar diseases. However, it involves risks to injure the lumbar plexus and abdominal large vessels when it gains access to the lumbar spine via lateral approach that passes through the retroperitoneal fat and psoas major muscle. This study was aimed to determine the distribution of psoas major and abdominal large vessels at lumbar intervertebral spaces in order to select an appropriate X/DLIF approach to avoid nerve and large vessels injury. Magnetic resonance imaging scanning on lumbar intervertebral spaces was performed in 48 patients (24 males, 24 females, 54.2 years on average). According to Moro's method, lumbar intervertebral space was divided into six zones A, I, II, III, IV and P. Thickness of psoas major was measured and distribution of abdominal large vessels was surveyed at each zone. The results show vena cava migrate from the right of zone A to the right of zone I at L1/2-L4/5; abdominal aorta was located mostly to the left of zone A at L1/2-L3/4 and divided into bilateral iliac arteries at L4/5; Psoas major was tenuous and dorsal at L1/2 and L2/3, large and ventral at L3/4 and L4/5. Combined with the distribution of nerve roots reported by Moro, X/DLIF approach is safe via zones II-III at L1/2 and L2/3, and via zone II at L3/4. At L4/5, it is safe via zones I-II in left and via zone II in right side, respectively.

Osteoporosis is a disease that significantly influences life expectancy and quality in humans. Oxidative stress may stimulate bone marrow osteoclast differentiation and inhibit osteoblast (OB) differentiation. OB proliferation and differentiation are affected by the forkhead box O (FoxO)1/β‑catenin signaling pathway. The osteogenic differentiation of mesenchymal stem cells (MSCs) may be promoted by silent information regulator type‑1 [sirtuin (SIRT)1]. However, the molecular mechanism of SIRT1 regulation of osteogenic differentiation of MSCs remains unclear, and further elucidation is needed. The present study investigated the role of SIRT1 in the FoxO1/β‑catenin signaling pathway in oxidative stress and its mechanism in the osteoblastic progenitor cell line (MC3T3‑E1). The results demonstrated that OB apoptosis and elevated oxidative stress in cells were simulated by H2O2, which was inhibited by moderate SIRT1 overexpression through reducing the oxidative stress. Further studies revealed that FOXO1 and β‑catenin pathway activity was downregulated by SIRT1 and eventually resulted in inhibition of target genes, including the proapoptotic gene B cell lymphoma‑2 interacting mediator of cell death, DNA repair gene growth arrest and DNA damage inducible protein 45 and the OB differentiation suppressor gene peroxisome proliferator activated receptor (PPAR)‑γ. Furthermore, β‑catenin and PPAR‑γ were inhibited by SIRT1. Overall, the results of the present study suggest that moderate overexpression of SIRT1 (~3‑fold of normal level) may directly or indirectly inhibit apoptosis of OBs via the FOXO1 and β‑catenin signaling pathway.

Transplantation of olfactory ensheathing cells (OECs) has emerged as a very promising therapy for spinal cord injury (SCI). Also, local delivery of NT-3 can counteract pathological events and induce a regenerative response after SCI. Supplement of exogenetic NT-3 might be a new approach to SCI repair. In this study, we examined the therapeutic effect of rat NT-3 gene-modified OECs transplantation on SCI. Rat NT-3 gene was transfected into OECs using a retroviral system. The engineered NT-3-OECs were tested for their ability to express and secrete biologically active NT-3 in vitro. Then NT-3-OECs were implanted into contused T9 spinal cord of the adult rats. Their ability of survival and NT-3 production was examined. The effect of axon regeneration was evaluated at the morphological level and promotion of locomotor functional recovery were assessed. The result showed that genetically modified OECs were capable of surviving and producing NT-3 in vivo to significantly improve the recovery after SCI.