Objective:To compare the clinical effect of transpedicular impaction and grafting of allogeneic bone containing enriched bone marrow combined with posterior internal fixation and posterior subtotal vertebrectomy combined with posterior internal fixation in the treatment of stage III Kümmell′s disease.Methods:A retrospective cohort study was made on clinical data of 40 patients with stage III Kümmell′s disease admitted to Zhengzhou Orthopedic Hospital from June 2015 to December 2018. There were 10 males and 30 females, at age range of 57-79 years［(67.7±6.1)years］. A total of 19 patients were treated by transpedicular impaction and grafting of allogeneic bone containing enriched bone marrow combined with posterior internal fixation (impaction bone graft group), and 21 patients by posterior subtotal vertebrectomy combined with posterior internal fixation (subtotal vertebrectomy group). Operation time and intraoperative blood loss were compared between the two groups. Degree of pain, lumbar dysfunction and degree of kyphosis were evaluated by visual analogue scale (VAS), Japanese Orthopedic Association (JOA) score and kyphotic Cobb angle before operation, at 1 week after operation and at the last follow-up. Bone healing time was compared between the two groups. The complications of the two groups were observed.Results:All patients were followed up for 25-64 months［(40.6±10.4)months］. Operation time and intraoperative blood loss were (130.0±10.1)minutes and (284.5±43.5)ml in impaction bone graft group, lower than those in subtotal vertebrectomy group［(253.8±33.2)minutes, (889.1±95.7)ml］(both P<0.01). There were no significant differences in VAS, JOA score or kyphotic Cobb angle between the two groups before operation, at 1 week after operation and at the last follow-up (all P>0.05). Both VAS and JOA score showed significant differences within each group at any time point (all P<0.01). In both groups, the kyphotic Cobb angle reduced significantly at 1 week after operation when compared with that before operation (all P<0.01), and the angle showed a slight increase at the last follow-up, but remained significantly lower than that before operation (all P<0.01). There were no relapse of pain or aggravation of kyphosis. Bone healing time in impaction bone graft group［4.4(4.0, 5.0)months］was significantly shorter than that in subtotal vertebrectomy group［6.4(5.2, 8.1)months］( P<0.01). There were 2 patients with delayed healing of surgical incision in impaction bone graft group, with the complication rate of 11%. There were 2 patients with dural tear and 3 patients with delayed healing of surgical incision in subtotal vertebrectomy group, with the complication rate of 24%. The complication rate was not statistically significant between the two groups ( P>0.05). No loosening or breakage of internal fixation was observed during the follow-up. Conclusions:Transpedicular impaction and grafting of allogeneic bone containing enriched bone marrow combined with posterior internal fixation and posterior subtotal vertebrectomy combined with posterior internal fixation are effective in the treatment of stage III Kümmell disease. However, the former can shorten the operation time, reduce the intraoperative blood loss and accelerate the healing of injured vertebral bone, suggesting a relatively minimally invasive surgical method for reconstruction and maintenance of spinal biomechanical stability.

Background Exposure to benzo[a]pyrene (BaP) may impair lung function through various mechanisms; however, it remains uncertain whether BaP induces ferroptosis in lung tissue cells, resulting in lung function impairment. Objective To investigate the ferroptosis of lung tissue cells triggered by subchronic BaP exposure in mice and its correlation with lung injury, and to explore the function of ferroptosis in BaP-induced lung tissue damage. Method Seventy-two healthy 3-weeks-old male C57BL/6J mice were acclimatized for 1 week and then randomly divided into six groups: control group (corn oil 10 mL·kg⁻¹), low-dose BaP group (2.5 mg·kg⁻¹), medium-dose BaP group (5 mg·kg⁻¹), high-dose BaP group (10 mg·kg⁻¹), BaP+ferrostatin-1 (Fer-1) group (10 mg·kg⁻¹+1 mg·kg⁻¹), and Fer-1 group (1 mg·kg⁻¹), with 12 mice each group. Corn oil and BaP were administered via gavage every other day, followed by an intraperitoneal injection of Fer-1 the subsequent day, throughout a period of 90 d. Whole-body plethysmography was applied to detect lung function; hematoxylin-eosin staining (HE) and Masson staining were used to observe lung tissue injury and fibrosis; microscopy of alveolar epithelial cells was conducted to reveal mitochondrial morphology; biochemical assays were used to measure the content of tissue iron, malondialdehyde (MDA), and glutathione (GSH), as well as the activity of glutathione peroxidase (GSH-Px); Western blotting and real-time quantitative PCR (RT-qPCR) analyses were performed to reveal the protein and mRNA expression of ferroptosis markers. Results Compared to the control group, the high-dose BaP group showed a significant increase in expiration time (Te) (P<0.01), and a significant decrease in ratio rate of achieving peak expiratory flow (Rpef), tidal volume (TVb), peak inspiratory flow (PIF), minute volume (MVb), and peak expiratory flow (PEF) (P<0.05 or 0.01). Based on the results of HE and Masson staining, partial destruction of alveolar structures, thickening of alveolar walls, infiltration of inflammatory cells, significant thickening of tracheal walls and a large deposition of collagen fibers in lung tissue were observed in the medium- and high-dose BaP groups. By microscopy, the alveolar epithelial cells exposed to low-dose BaP showed condensed chromatin, and the mitochondria exposed to medium and high-dose BaP showed wrinkles, increased mitochondrial membrane density, and diminished mitochondrial cristae. Compared to the control group, in the medium- and high-dose BaP groups, the lung tissue iron content and the expression levels of ACSL4 protein and mRNA significantly elevated (P<0.01 or 0.05), while the mRNA expression level of SLC7A11 significantly decreased (P<0.05); in the high-dose BaP group, the MDA content, COX2 protein, and PTGS2 mRNA expression levels significantly increased (P<0.05 or 0.01), GSH content and GSH-Px activity, GPX4 protein and mRNA expression levels, and the expression level of SLC7A11 protein significantly decreased (P<0.01 or 0.05). The ferroptosis inhibitor Fer-1 markedly reversed respiratory function, morphology, mitochondrial alterations, and the aforementioned ferroptosis-related biochemical indicators. Conclusion Subchronic exposure to BaP can induce ferroptosis in mice lung tissue cells, resulting in compromised lung function.