Objective To investigate the effect of tetramethylpyrazine (TMP) with a certain concentration added to vitrification solution on peripheral nerve allografts regeneration. Methods Forty-eight healthy clean SD male rats were selected as donors, and 96 healthy clean Wistar male rats as recipients, all rats being 3 months old and weighing 200-250 g. The sciatic nerves segments of 15 mm were removed from the donors, then randomly divided into 4 groups according to vitrificationsolution containing TMP. No TMP was used in group A as the control group; 100 mg/L, 200 mg/L and 400 mg/L TMP were used in group B, group C and group D, respectively. Then them were cryo-preserved at — 196 ℃ for 3 weeks. Nerve defect of 10 mm in length was made in the sciatic nerves of recipients. After rewarming, the allografts were transplanted to the corresponding rats. The gross appearance, the morphological and electrophysiological changes, the image analysis of axons and motor end-plate were detected at 4, 8, 12 and 16 weeks. Results All rates survived to the end of the experiment. The adhesion and edema of allografts in group A and group B were obvious 4 weeks after operation; then adhesion and edema was obvious in group A and were improved in the other groups 8 weeks after operation. Adhesion was observed in groups A and B; no adhesion was observed in groups C and D at 12 weeks. The number of regeneration nerve, the latent, the ampl itude, the nerve conduction velocity, the medullary sheath/μm2, the medullary sheath density/μm2 and the image analysis of axons and motor end-plate in groups A and B were significantly lower than those in groups C and D (P lt; 0.01); and there were no significant differences between groups C and D (P gt; 0.05). The observation of transmission electron microscope showed that medullated nerve fibers and myel in sheath of groups C and D were thicker than groups A and B, layers of groups C and D were clear. Conclusion The vitrification solution with 200 mg/L tetramethylpyrazine has protective effect on regeneration of peripheral nerve allografts．
Objective To observe the effect of tetramethypyrazine (TMP) on the expression of hypoxia-related factors in human umbilical vein endothelial cells (HUVECs). Methods The second to fifth passage cultured HUVECs were divided into five groups: control group, CoCl2induced hypoxic group and 50, 100, 200 mu;mol/L TMP treatment groups. HUVECs in control group were not treated. HUVECs inCoCl2induced hypoxic group were treated with 150 mu;mol/LCoCl2for four hours. HUVECs in 50, 100, 200 mu;mol/L TMP treated groups were pretreated with 150 mu;mol/LCoCl2 for four hours, followed by treatment with 50, 100, 200 mu;mol/L TMP for eight hours. Real-time reverse transcription-polymerase chain reaction (RT-PCR) was used to detect the mRNA levels of prolyl hydroxylase 2 (PHD2), hypoxia-induced factor-1alpha;(HIF-1alpha;) and vascular endothelial growth factor (VEGF). Protein levels of PHD2, HIF-1alpha;, and VEGF were detected using Western blot. Results Compared with the control group, theCoCl2 induced hypoxic group showed decreased mRNA and protein levels of PHD2 (t=3.734, 3.122;P＜0.05), while those of HIF-1alpha; and VEGF increased (HIF-1alpha; mRNA:t=4.589,P＜0.05; HIF-1alpha; protein:t=3.778,P＜0.05. VEGF mRNA:t=3.926,P＜0.05; VEGF protein:t=3.257,P＜0.05). Compared with theCoCl2 induced hypoxic group, 50, 100, 200 mu;mol/L TMP treated groups showed increased mRNA and protein levels of PHD2 (PHD2 mRNA: t=3.286, 3.617, 3.886;P＜0.05. PHD2 protein: t=2.813, 3.026, 3.078; P＜0.05); while those of VEGF decreased (VEGF mRNA: 50 mu;mol/L TMP: t=1.696,P＞0.05; 100 mu;mol/L TMP:t=2.974,P＜0.05; 200 mu;mol/L TMP: t=3.492,P＜0.05; VEGF protein: 50 mu;mol/L TMP: t=1.986,P＞0.05; 100 mu;mol/L TMP: t=2.976,P＜0.05; 200 mu;mol/L TMP:t=3.136,P＜0.05); although changes in HIF-1alpha;mRNA levels were not statistically significant (t=1.025, 0.726, -1.386;P＞0.05), showed a decrease in HIF-1alpha;protein levels (50 mu;mol/L TMP: t=2.056,P＞0.05; 100 mu;mol/L TMP:t=3.058,P＜0.05; 200 mu;mol/L TMP:t=3.828,P＜0.05). ConclusionIn HUVECs, TMP can upregulate the mRNA and protein expression of PHD2, while down regulating HIF-1alpha; protein expression and VEGF mRNA and protein expression under acute hypoxic conditions.
Objective To evaluate the efficacy and safety of tetramethylpyrazine (TMP) for diabetic peripheral neuropathy (DPN). Methods Randomized controlled trials were identified from CBM (1978-2003.3), TCMLRS (1980-2003.3), Medline (1970-2003.3), EMbase (1970-2003.3) and Cochrane Library (issue 3, 2003). We handsearched Journal of Traditional Chinese Medicine (1990-2002), New Chinese Medicine (1990-2002), Chinese Journal of Integrated Traditional and Western Medicine (1990-2002) and Research of Traditional Chinese Medicine (1990-2002). Papers of the controlled trials of clinical therapeutic studies on DPN treatment by Chinese medicine herb TMP were included and analyzed according to the criteria of the Cochrane Handbook in 1997. Results Six RCTs involving 669 patients were included, with all trials of low methodological quality. Meta-analysis indicated TMP was more effective than western medicine on pain or numbness of extremities of DPN [The pooled OR = 10.12, 95%CI (6.70 to15.28), P=0.000] and motor nerve conduction velocity change of common peroneal nerves and median nerves . Only one trial reported the side effects of TMP, such as dizziness and headache. Conclusions Based on the review, TMP infusion may have positive effect on DPN. However, the evidence is not b enough due to the general low methodological quality, so we can’t draw a reliable conclusion about the effects of TMP for DPN at the moment. Further large randomized, double blind, placebo-controlled trial are needed.