Tetramethylpyrazine Facilitates Functional Recovery after Spinal Cord Injury by Inhibiting MMP2, MMP9, and Vascular Endothelial Cell Apoptosis.

BACKGROUND: Spinal cord injury (SCI) is a major public health issue that leads to neurological dysfunctions and morbidities in patients. Tetramethylpyrazine (TMP) plays a neuroprotective role in SCI; however, the underlying mechanism has not been fully elucidated. OBJECTIVE: In the present study, we aimed to investigate the mechanisms and therapeutic effects of TMP on SCI. METHODS: A contusion SCI model was established that used a modified Allen's method. In the TMP group, TMP (200 mg/kg) was injected daily for 5 days post-injury, while in the Negative Control (NC) group, an equal volume of normal saline was injected. Hindlimb motor function was evaluated using the Basso, Beattie, Bresnahan (BBB) scale. The effects of TMP on protein levels of the matrix metalloproteinases 2 (MMP2) and 9 (MMP9), Bax and cleaved caspase-3 were determined by western blotting. Apoptotic changes in vascular endothelial cells were evaluated using immunofluorescence and TUNEL staining. Alterations in 3D vessel morphology after treatment with TMP were assessed by synchrotron radiation micro-CT (SRµCT). RESULTS: TMP treatment significantly improved recovery in hindlimb motor function and attenuated vascular endothelial cell apoptosis in rats with SCI. Additionally, TMP treatment markedly decreased the protein levels of MMP2 and MMP9, pro-apoptotic bax and cleaved caspase-3 while promoting angiogenesis, as evidenced by vessel visualization using SRµCT. CONCLUSION: These results indicate that TMP attenuated SCI-induced neurological impairments by the down-regulation of the expression of MMP2 and MMP9 proteins, the inhibition of vascular endothelial cell apoptosis, and the promotion of angiogenesis.

Synchrotron radiation micro-CT as a novel tool to evaluate the effect of agomir-210 in a rat spinal cord injury model.

MicroRNA-210 (miR-210) was initially reported to be associated with hypoxia and plays a vital role in modulating angiogenesis. However, the potential effect and underlying mechanisms of miR-210 activity in rat spinal cord injury (SCI) have not yet been fully illuminated. In the present study, differential microRNA expression after SCI was determined by Microarray analysis. To explore the effect of miR-210 after SCI, we intrathecally injected agomir-210 with Alzet Osmotic Pumps to up-regulated the endogenous miR-210 expression. Then, synchrotron radiation micro-CT (SRµCT) imaging was used to investigate the effect of agomir-210 in rat SCI model. We found that the endogenous miR-210 expression could be up-regulated by intrathecal agomir-210 injection. The administration of agomir-210 significantly promoted angiogenesis, as evidenced by increased vessel number and volume detected by SRµCT, attenuated the lesion size and improved functional recovery after SCI. Additionally, agomir-210 attenuated cellular apoptosis and inflammation in the injured rat spinal cord. Expression levels of pro-apoptotic protein (Bax) and pro-inflammatory cytokines (TNF-α and IL-1ß) were significantly decreased after agomir-210 treatment, whereas expression levels of anti-apoptotic (Bcl-2) and anti-inflammatory (IL-10) proteins were up-regulated. In conclusion, our results indicated that SRµCT is a powerful imaging tool to evaluate the effects of angiogenesis after agomir-210 administration in rat SCI model. The up-regulation of endogenous miR-210 expression following agomir-210 administration promoted angiogenesis and anti-apoptotic protein expression, and attenuated inflammation. MiR-210 played a positive role in neurological functional recovery and could be a potential new therapeutic target for SCI.

Taurine inhibits serum deprivation-induced osteoblast apoptosis via the taurine transporter/ERK signaling pathway

Taurine has positive effects on bone metabolism. However, the effects of taurine on osteoblast apoptosis in vitro have not been reported. The aim of this study was to investigate the activity of taurine on apoptosis of mouse osteoblastic MC3T3-E1 cells. The data showed that 1, 5, 10, or 20 mM taurine resulted in 16.7, 34.2, 66.9, or 63.75 percent reduction of MC3T3-E1 cell apoptosis induced by the serum deprivation (serum-free α-MEM), respectively. Taurine (1, 5, or 10 mM) also reduced cytochrome c release and inhibited activation of caspase-3 and -9, which were measured using fluorogenic substrates for caspase-3/caspase-9, in serum-deprived MC3T3-E1 cells. Furthermore, taurine (10 mM) induced extracellular signal-regulated kinase (ERK) phosphorylation in MC3T3-E1 cells. Knockdown of the taurine transporter (TAUT) or treatment with the ERK-specific inhibitor PD98059 (10 μM) blocked the activation of ERK induced by taurine (10 mM) and abolished the anti-apoptotic effect of taurine (10 mM) in MC3T3-E1 cells. The present results demonstrate for the first time that taurine inhibits serum deprivation-induced osteoblast apoptosis via the TAUT/ERK signaling pathway.

Taurine inhibits serum deprivation-induced osteoblast apoptosis via the taurine transporter/ERK signaling pathway.

Taurine has positive effects on bone metabolism. However, the effects of taurine on osteoblast apoptosis in vitro have not been reported. The aim of this study was to investigate the activity of taurine on apoptosis of mouse osteoblastic MC3T3-E1 cells. The data showed that 1, 5, 10, or 20 mM taurine resulted in 16.7, 34.2, 66.9, or 63.75% reduction of MC3T3-E1 cell apoptosis induced by the serum deprivation (serum-free α-MEM), respectively. Taurine (1, 5, or 10 mM) also reduced cytochrome c release and inhibited activation of caspase-3 and -9, which were measured using fluorogenic substrates for caspase-3/caspase-9, in serum-deprived MC3T3-E1 cells. Furthermore, taurine (10 mM) induced extracellular signal-regulated kinase (ERK) phosphorylation in MC3T3-E1 cells. Knockdown of the taurine transporter (TAUT) or treatment with the ERK-specific inhibitor PD98059 (10 µM) blocked the activation of ERK induced by taurine (10 mM) and abolished the anti-apoptotic effect of taurine (10 mM) in MC3T3-E1 cells. The present results demonstrate for the first time that taurine inhibits serum deprivation-induced osteoblast apoptosis via the TAUT/ERK signaling pathway.