Lentivirus-mediated transfer of gene encoding fibroblast growth factor-18 inhibits intervertebral disc degeneration.

Fibroblast growth factor 18 (FGF-18) is a well-characterized anabolic growth factor involved in cartilage homeostasis. However, the effect of FGF-18 on intervertebral disc (IVD) degeneration has not been investigated. The present study aimed to investigate the role of FGF-18 in the process of rabbit IVD degeneration. In vitro, primary nucleus pulposus cells (NPs) were cultured and transfected with a lentivirus. Tert-butyl hydroperoxide (TBHP) was used to induce apoptosis in NPs on the second passage, while overexpression of FGF-18 in NPs attenuated TBHP-induced apoptosis. A rabbit annular puncture model was generated to induce IVD degeneration in vivo. The discs were injected with an FGF-18-overexpression lentivirus or a negative control lentivirus. In the sham group, the discs were exposed and not punctured. Disc degeneration was evaluated using H&E staining and a histological grading system. Reverse transcription-quantitative PCR was used to detect the expression of the extracellular matrix-degrading enzymes matrix metalloproteinase-3 (MMP-3) and A disintegrin and metalloproteinase with thrombospondin motifs 5 (ADAMTS-5). Nucleus pulposus apoptosis was detected via western blotting, immunohistochemical methods and TUNEL staining. Histologic examination showed that disc degeneration was attenuated after FGF-18 overexpression treatment. At 8 weeks after surgery, the expression of MMP-3 and ADAMTS-5 in the annular puncture groups was higher compared with in the sham group. FGF-18 treatment inhibited the expression of MMP-3 and ADAMTS-5 at the mRNA level. Western blot assays indicated that the expression level of Bax was significantly reduced in the FGF-18 groups, and that the expression level of Bcl-2 was significantly increased compared with those in the control group. Moreover, immunohistochemical analysis indicated that the FGF-18 group exhibited a lower percentage of cleaved caspase 3-positive NPs. Quantification of the TUNEL staining demonstrated that the FGF-18 group had fewer apoptotic NPs than the control group. These findings indicated that FGF-18 could delay IVD degeneration by inhibiting the apoptosis of NPs and the expression of matrix-degrading enzymes.

[Clinical outcomes of spinal endoscopic surgery for tiny lumbar disc herniation with severe radiating pain of lower limb].

OBJECTIVE: To study the clinical characteristics of the patients with tiny lumbar disc herniation and severe symptoms(tLDHSS) and the therapeutic effects of percutaneous endoscopic lumbar discectomy(PELD). METHODS: From January 2014 to February 2019, 34 patients with tLDHSS were reviewed retrospectively, including 20 males and 14 females, aged from 31 to 73 (48.8±10.1) years, with a follow up duration ranged from 8 to 48 (21.8±10.3) months. The clinical manifestations, imaging and surgical data were analyzed. The visual analogue scale (VAS) and Oswestry Disability Index (ODI) scores were analyzed before operation, 1 month after operation and at the latest follow-up. The preoperative and postoperativescores were compared. At the latest follow up, the Macnab system was used to evaluate the effects of the operation. RESULTS: The main symptom of 34 cases was severe radiation pain on one side of lower limbs. The duration of preoperative symptoms ranged from 0.33 to 84 months. The disc herniation was found in 7 cases of L4, 5 and 27 cases of L5S1. According to the MSU division of lumbar disc herniation, 31 cases were located in area B. In all cases, it was confirmed that the protruding nucleus compressed the nerve root, and in 26 cases, the nerve root was obviously inflamed. The operation time ranged from 30 to 80 min, with a mean time of (43.5±9.5) min. The preoperative VAS score was 8.1±1.3 and ODI score was 31.8±6.7. And the VAS score was 1.1± 0.3, 0.7±0.4 on the first month after operation and the latest follow up, respectively. The ODI score was 5.3±2.1 and 0 to 10 (with a median score of 2) on the first month after operation and the latest follow-up respectively. The postoperative VAS and ODI scores were improved compared with preoperative scores.At the latest follow up, 28 cases got an excellent result and 6 cases good according to Macnab evaluation system. During the follow-up period, only one patient had recurrent disc herniation. CONCLUSION: The main symptom of patients with tLDHSS is severe radiation pain on one side of lower limb. It manifests as sudden onset and shorter course of disease. Severe local inflammation was induced by local compression of the protruding nucleus pulposus on the nerve root out of the dura. For this kind of patients, thin layer CT scan has an important diagnostic value. In the treatment of this kind of patients, the symptoms are relieved rapidly, the curative effect is definite and the recurrence rate is low.

AMP-activated protein kinase-dependent induction of autophagy by erythropoietin protects against spinal cord injury in rats.

AIMS: Autophagy has been regarded as a promising therapeutic target for spinal cord injury (SCI). Erythropoietin (EPO) has been demonstrated to exhibit neuroprotective effects in the central nervous system (CNS); however, the molecular mechanisms of its protection against SCI remain unknown. This study aims to investigate whether the neuroprotective effects of EPO on SCI are mediated by autophagy via AMP-activated protein kinase (AMPK) signaling pathways. METHODS: Functional assessment and Nissl staining were used to investigate the effects of EPO on SCI. Expressions of proteins were detected by Western blot and immunohistochemistry. RESULTS: Treatment with EPO significantly reduced the loss of motor neurons and improved the functional recovery following SCI. Erythropoietin significantly enhanced the SCI-induced autophagy through activating AMPK and inactivating mTOR signaling. The inhibitor of AMPK, compound C, could block the EPO-induced autophagy and beneficial action on SCI, whereas the activator of AMPK, metformin, could mimic the effects of EPO. In the in vitro studies, EPO enhanced the hypoxia-induced autophagy in an AMPK-dependent manner. CONCLUSIONS: The AMPK-dependent induction of autophagy contributes to the neuroprotection of EPO on SCI.

Inhibition of Autophagy by Estradiol Promotes Locomotor Recovery after Spinal Cord Injury in Rats.

17ß-estradiol (E2) has been shown to have neuroprotective effects in different central nervous system diseases. The mechanisms underlying estrogen neuroprotection in spinal cord injury (SCI) remain unclear. Previous studies have shown that autophagy plays a crucial role in the course of nerve injury. In this study, we showed that E2 treatment improved the restoration of locomotor function and decreased the loss of motor neurons in SCI rats. Real-time PCR and western blot analysis revealed that the protective function of E2 was related to the suppression of LC3II and beclin-1 expression. Immunohistochemical study further confirmed that the immunoreactivity of LC3 in the motor neurons was down-regulated when treated with E2. In vitro studies demonstrated similar results that E2 pretreatment decreased the autophagic activity induced by rapamycin (autophagy sensitizer) and increased viability in a PC12 cell model. These results indicated that the neuroprotective effects of E2 in SCI are partly related to the suppression of excessive autophagy.