Tetramethylpyrazine in a Murine Alkali-Burn Model Blocks NFκB/NRF-1/CXCR4-Signaling-Induced Corneal Neovascularization.

Purpose: Tetramethylpyrazine (TMP) is the active ingredient extracted from the Chinese herb Chuanxiong. The purpose of our study was to identify the mechanism of therapeutic TMP suppression of pathologic chemokine receptor 4 (CXCR4) transcription. Methods: C57BL/6J mice with alkali-burned corneas were treated with either TMP eye drops (1.5 mg/mL) or PBS. Corneal neovascularization (CNV) was measured and a clinical assessment was made by slit lamp microscopy. Expression of CXCR4 and the transcription factors nuclear respiratory factor-1 (NRF-1), nuclear factor kappa B (NFκB), forkhead box C1, and yin yang 1 were tracked by real-time RT-PCR and immunofluorescence staining of murine corneas. Western blot, real-time PCR, and immunofluorescence evaluated expression of related genes in human umbilical vein endothelial cells (HUVECs) after 200-µmol/L TMP treatment. In addition, plasmid transfection and chromatin immunoprecipitation assays elucidated the relationship among NRF-1, NFκB, and CXCR4. Results: Corneas treated with TMP had smaller areas of neovascularization and scored better in clinical assessments. Injured corneas showed significantly elevated expressions of NRF-1, NFκB, and CXCR4 that were normalized in vivo by TMP treatment. Similarly, in HUVECs in vitro, TMP decreased expression of NRF-1, NFκB, and CXCR4. Overexpression of NFκB or NRF-1 raised the expression of CXCR4 in HUVECs, but not synergistically. Chromatin immunoprecipitation assays detected only NRF-1 bound to the CXCR4 promoter region, suggesting NFκB controls CXCR4 expression by upregulating NRF-1. Together, our data suggest TMP downregulates CXCR4 by repressing NRF-1 expression in CNV, likely indirectly by downregulating NFκB. Conclusions: Our results implicate a novel mechanism wherein TMP inhibits neovascularization via an NFκB/NRF-1/CXCR4 circuit.

Tetramethylpyrazine-mediated regulation of CXCR4 in retinoblastoma is sensitive to cell density.

Retinoblastoma is the most common ocular tumor in children, and it causes extensive damage. Current treatment options for retinoblastoma include surgery, chemotherapy, radiotherapy and cryotherapy. However, the majority of chemotherapy medicines cause complications and side effects that lead to severe impairment of patient health. Previous studies have reported that tetramethylpyrazine (TMP), which is an extract of the Chinese herbal medicine Chuanxiong, reduces the risk of multidrug resistance in chemotherapy and inhibits the proliferation and metastasis of various types of cancer cells. However, the underlying molecular mechanism of TMP in retinoblastoma remains unclear. The current study demonstrated that C-X-C chemokine receptor type 4 (CXCR4) was expressed in WERI­Rb1 cells and in retinoblastoma. Using reverse transcription­quantitative polymerase chain reaction and western blotting techniques, the current study demonstrated that TMP significantly downregulated the expression of CXCR4 in WERI­Rb1 cells cultured at high density, whereas it had a minor effect in low­density WERI­Rb1 cells; additionally, this effect occurred in a time­dependent manner. TMP inhibited the proliferation of WERI­Rb1 cells as effectively as a CXCR4 antagonist, AMD3100, consistent with a role of CXCR4 in cancer development. Notably, TMP did not affect the cell cycle of cells cultured at low density (1x105 cells/ml), whereas it induced G1­phase arrest in high­density cells (7.5x105 cells/ml; P<0.05). In addition, the expression of CXCR4 in primary rat retinal neurocytes was significantly downregulated by TMP treatment, and this treatment protected primary rat retinal neurocytes from H2O2­induced damage. Thus, the results of this study indicate that TMP is a potential candidate for use in treatment of retinoblastoma, and also provides novel insights into the mechanisms of the anti­cancer and neuroprotective effects of this extract.

[Ultrasound-guided percutaneous tube drainage combined with directly-viewed debridement with cholangioscopy: a mini-invasive strategy for peripancreatic necrotizing infection].

OBJECTIVE: To establish "an integrative therapy" of drainage and debridement on peripancreatic necrotizing infection (PPNI) with minimally invasive technique, and to detect its clinical effects. METHODS: There were 17 patients who accepted ultrasound-guided percutaneous tube drainage combined with directly-viewed debridement with cholangioscopy from March 2006 to January 2008. Percutaneous puncture and catheter (6 - 8 F) drainage were adopted on the patients suffering from PPNI with B-us guidance, then the drainage sinus was expanded progressively from 8 F to 24 F in diameter with Cook fascia dilator by degrees, and the 22 F or 24 F tube was easily placed into the interior of PPNI instead of the prior catheter. So a better drainage effect was achieved. One week later, the necrotizing tissue of PPNI could be observed and debrided with choledochoscope under a directly-viewed way through the enlarged new sinus. Thus, with the continuous tube drainage and repeated debridement, the focus was absorbed and covered gradually. RESULTS: Seventeen cases accepted the mini-invasive therapy, 15 cases were saved finally with cure rate of 88.2%, and 2 cases conversion to laparotomy because of some technical reasons. The mean healing time was 73 days, and the mean hospitalization time was 57 days. Bleeding was occurred in 2 cases localized in sinus and the inside of PPNI, digestive tract fistula was detected in 2 cases, and these patients with the complications were cured under nonoperative management. All the patients were still alive with following-up, neither remains nor recurrence of the PPNI was found in our group. CONCLUSIONS: Ultrasound-guided percutaneous tube drainage combined with directly-viewed debridement with cholangioscopy, as a mini-invasive therapy, could complete the goal-directed therapy of PPNI, meanwhile, realize the modern surgery ideal of damage control.