Search

Levofloxacin, a fluoroquinolone, is a widely-used and effective antibiotic. However, various adverse side effects are associated with levofloxacin. The purpose of this study was to further explore the effects of levofloxacin on rat nucleus pulposus cells (NPCs). Inverted phase-contrast microscopy, flow cytometry and caspase-3 activity assays were used and revealed that serum deprivation induced apoptosis, which was markedly increased by levofloxacin in a dose-dependent manner. Simultaneously, levofloxacin decreased cell binding to type II collagen (COL2). Thus, levofloxacin-induced apoptosis exhibits characteristics of anoikis, the process by which cell death is triggered by separation from the extracellular matrix, which contains COL2. Furthermore, real-time quantitative RT-PCR was used to further confirm that levofloxacin downregulates COL2 expression in a dose-dependent manner. At last, western blot was used to find that levofloxacin increased the ratio of Bax/Bcl-2 and active caspase-3 in a dose-dependent manner. Levofloxacin therefore increases the effects of serum deprivation on anoikis by downregulating COL2 in rat NPCs in vitro via Bax/Bcl-2/caspase-3 pathway. This research provides a novel insight into the mechanisms of levofloxacin-induced toxicity and may potentially lead to a better understanding of the clinical effects of levofloxacin, especially in terms of intervertebral disc degeneration.

Levofloxacin was previously reported to induce apoptosis of rat annulus fibrosus (AF) cells by upregulating active caspase-3 and matrix metalloproteinase (MMP)-3 expression in vitro. However, the effects of levofloxacin on rat AF cells, as well as the related mechanism, have not been revealed completely. The purpose of this study was to further explore the changes in extracellular matrix and MMPs of rat AF cells based on levofloxacin-induced apoptosis. AF cells isolated from rat AF regions were cultured in monolayers and treated with levofloxacin in a dose- and time-dependent manner. To determine the cytotoxic effects of levofloxacin, inverted phase-contrast microscopy was used to perform morphological observation of apoptotic cells. The mRNA expression levels of MMP-2, -9 and -13 were quantified by reverse transcription and real-time quantitative polymerase chain reaction (RT-qPCR). Protein level of MMP-2 and MMP-13 were determined by western blot. The results showed that levofloxacin induced marked AF cell apoptosis, which was observed by inverted phase-contrast microscopy, and indicated by the increased expression of active caspase-3. Both RT-qPCR and western blot revealed that MMP-2 and MMP-13 expression were upregulated by levofloxacin treatment in a time- and dose-dependent manner. Moreover, cellular binding to type I collagen was found to be decreased by levofloxacin. In conclusion, the results above suggest that the possible cytotoxic effects of levofloxacin on AF cells in vitro may be attributed to the decreased cell binding to type I collagen and up-regulated expression of MMP-2 and MMP-13.

A multicenter retrospective study.The purpose of this study was to explore risk factors of dysphagia after anterior cervical surgery and factors affecting rehabilitation of dysphagia 2 years after surgery.Patients who underwent anterior cervical surgery at 3 centers from January 2010 to January 2013 were included. The possible factors included 3 aspects: demographic variables-age, sex, body mass index (BMI): hypertension, diabetes, heart disease, smoking, alcohol use, diagnose (cervical spondylotic myelopathy or ossification of posterior longitudinal ligament), preoperative visual analogue scale (VAS), Oswestry Disability Index (ODI), Japanese Orthopaedic Association (JOA), surgical-related variables-surgical option (ACDF, ACCF, ACCDF, or Zero profile), operation time, blood loss, operative level, superior fusion segment, incision length, angle of C2 to C7, height of C2 to C7, cervical circumference, cervical circumference/height of C2 to C7.The results of our study indicated that the rate of dysphagia at 0, 3, 6, 12, and 24 months after surgery was 20%, 5.4%, 2.4%, 1.1%, and 0.4%, respectively. Our results showed that age (58.8 years old), BMI (27.3 kg/m), course of disease (11.6 months), operation time (103.2 min), blood loss (151.6 mL), incision length (9.1 cm), cervical circumference (46.8 cm), angle of C2 to C7 (15.3°), cervical circumference/height of C2 to C7 (4.8), preoperative VAS (7.5), and ODI (0.6) in dysphagia group were significantly higher than those (52.0, 24.6, 8.6, 88.2, 121.6, 8.6, 42.3, 12.6, 3.7, 5.6, and 0.4, respectively) in nondysphagia group; however, height of C2 to C7 (9.9 vs 11.7 cm) and preoperative JOA (8.3 vs 10.7) had opposite trend between 2 groups. We could also infer that female, smoking, diabetes, ossification of posterior longitudinal ligament, ACCDF, multilevel surgery, and superior fusion segment including C2 to C3 or C6 to C7 were the risk factors for dysphagia after surgery immediately. However, till 2 years after surgery, only 2 risk factors, smoking and diabetes, could slow rehabilitation of dysphagia.Many factors could significantly increase rate of dysphagia after anterior cervical surgery. Operation time as a vital factor markedly increases immediate postoperative dysphagia and smoking, as the most important factor, lower recovery of dysphagia. Further study is needed to prove if these factors could influence dysphagia.

Background Fluoroquinolones are in wide clinical use as safe and effective antibiotics. Articular cartilage, tendons, and epiphyseal growth plates have been recognized as targets of fluoroquinolone-induced connective tissue toxicity. However, the effects of fluoroquinolones on annulus fibrosus (AF) cells are still unknown. Material/methods The main objective of this study was to investigate the effects of levofloxacin, a typical fluoroquinolone antibiotic drug, on rat AF cells in vitro. Rat annulus fibrosus (RAF) cells were treated with levofloxacin at different concentrations (0, 10, 20, 30, 40, 60, 80, and 90 μg/ml) and were assessed to determine the possible cytotoxic effects of levofloxacin. Inverted phase-contrast microscopy was used to accomplish the morphological observation of apoptosis of treated cells. Western blot and real-time quantitative RT-PCR (qPCR) was used to explore the expression of active caspase-3 and MMP-3. Flow cytometry was used to measure the apoptotic incidences. Results Our study showed that levofloxacin, with concentrations at 30, 60, and 90 μg/ml, induced dose-dependent RAF cell apoptosis and higher expression of caspase-3 and MMP-3. More apoptotic cells were observed by inverted phase-contrast microscopy. Moreover, levofloxacin increased the activity of caspase-3, and it also reduced cell viability with different concentrations ranging from 10 to 80 μg/ml. Conclusions Our study results suggest that levofloxacin has cytotoxic effects on RAF cells, characterized by enhancing apoptosis and reducing cell viability, and indicate a potential toxic effect of fluoroquinolones on RAF cells.