OBJECTIVE:To study the improvement effects of polydatin on renal fibrosis in rats and its mechanism. METH-ODS:50 rats was were randomly divided into sham operation group,model group,positive group(benazepril,5 mg/kg)and poly-datin high-dose and low-dose groups(100,50 mg/kg),with 10 rats in each group. Except for sham operation group,renal fibrosis model was induced by unilateral ureter obstruction. After modeling,administration groups were given relevant medicine intragastri-cally,and sham operation group and model group were given 0.5%sodium carboxymethyl cellulose solution once a day for consec-utive 4 weeks. The pathological change of renal tissue was scored. 24 h urinary protein and serum levels of urea nitrogen and creati-nine were determined,and the content of hydroxyproline,mRAN expression of TGF-β1 and FN were detected in renal tissue. RE-SULTS:Compared with sham operation group,pathological score,24 h urinary protein,serum levels of urea nitrogen and creati-nine,the content of hydroxyproline in renal tissue,mRNA expression of TGF-β1 and FN were all increased significantly (P<0.01). Compared with model group,24 h urinary protein,serum levels of urea nitrogen and creatinine and mRNA expression of FN in renal tissue decreased significantly in administation groups;the pathology scores,the content of hydroxyproline in renal tis-sue and mRNA expression of TGF-β1 of positive group and polydatin high-dose group were all decreased significantly(P<0.05 or P<0.01). CONCLUSIONS:Polydatin can prevent kidney fibrosis induced by unilateral ureteral obstruction,the mechanism of which may be associated with the mRNA expression down-regulation of TGF-β1 and FN in renal tissue.

Objective To construct the eukaryotic expression plasmid containing human epidermal growth factor(hEGF) gene with signal peptide(SP).Methods After two pairs of primers were designed and synthesized,the cDNA fragment of hEGF and SP genes were amplified from total RNAs. The amplified cDNA fragments were cloned into pGEM-T vector.The expression plasmids were verified by double endonuclease digestion and DNA sequence analysis. Results With RT-PCR using two pairs of primers,two bands(about 90bp and 180bp) were obtained and confirmed as signal peptide and EGF cDNA fragment with electrophoresis analysis and DNA sequencing after cloned into pGEM-T vector.The SP and EGF cDNA fragments were inserted into plasmid pcDNA3.1(+).The bands of 240bp and 5.4kb were obtained and identified as the full length of SP-EGF cDNA fragment by DNA sequence analysis.Conclusion The eukaryotic expression plasmids containing hEGF gene is successfully constructed.

Objective To explore the safety and effectiveness of diagnostic ultrasound associated with microbubbles to open the blood brain barrier(BBB).Methods Microbubbles were injected through caudal vein,the rat head was radiated by GE Vivid 7 diagnostic ultrasound immediately.The radiated depth was located in the basal ganglia assisted by magnetic resonance imaging(MRI)scanning.The degree of BBB opening was evaluated by enhanced MRI and Evans blue dyeing.The safety was inspected by observation of cell morphology under hematoxylin eosin(HE)staining.Results After the rat head radiated by diagnostic ultrasound with microbubbles,signal enhancement of the radiated area was observed on post contrast T1-weighted images.Red fluorescence of Evans blue was detected by fluorescence microscope in the same area.Normal cellular morphology and structural integrity were showed by HE staining.Conclusions The BBB of rat could be opened targetedly and noninvasively by diagnostic ultrasound associated with microbubbles.This may provide a new strategy for the drugs and stem cells treatment in the central nervous system diseases.

Objective To investigate the clinical efficacy and mechanism of vacuum-assisted closure (VAC) in the preoperative and postoperative treatment of bedsore united with skin flap.Methods Twenty two cases with bedsore were randomly divided into experimental and control groups.In the control group,the surgery of flap was performed after the treatment of continuous negative pressure about 7-10 days and the VAC was not applied after operation.While in the experimental group,VAC was not used before operation.It was applied on flaps as soon as sutured the border of flap and decubitus ulcers and removed after 7-10 days.By comparing the general appearance of two groups,microvessel count and the detection rate of bacterial culture and other indicators,the clinical effects of two treatments were investigated and the preliminary mechanism was analyzed.Results After preoperative VAC treatment,11 cases of control group showed a little granulation tissue growth,less subcutaneous hematoma and wound effusion,increased microvessel count and negative bacterial culture.However,there were 4 cases of death cavity residual,subcutaneous hematoma and wound effusion,positive bacterial culture and another 4 cases of delayed healing with skin flap repairing bedsore.The application of VAC in experimental group showed close contact of flap with the basement,less effusion,increased microvessel count and negative bacterial culture.One case of skin flap had a small area of separation,after the dressing of skin and the flap survived.The other wounds healed by first intention.Conclusions The use of VAC to repair bedsore can reduce the number of operation,and it is beneficial to the flap survival.

Objective To study the influence of let-7b on cell proliferation and aerobic glycolysis of human melanoma cell A375.Methods Transfect A375 cell line with hsa-let-7b oligonucleotide or antisense.Glucose and lactate in medium were determined by spectrophotometry at 24 h and 48 h time point after transfection.The cell proliferation was determined by methylthiazol tetrazolium (MTT) assay.Results Over expression of let-7b in melanoma cell reduced cell proliferation notably,compared to the other groups by MTT(P ＜0.05).However,the glucose consumption and lactate production differences were not observed during 24 h or 48 h ( P ＞ 0.05 ),the blank control group transformed about 57％ and 43％ glucose to lactate during 24 h and 48 h.Conclusions Melanoma cell line A375 has notably aerobic glycolysis hallmark,let-7b could inhibit proliferation of melanoma cell line A375,but it may has no influence on glucose metabolism.

Objective To confirm whether or not let-7b and miR-199a were significantly associated with malignant melanoma growth and proliferation. Methods An over -expression plasmid and an inhibitor, which targeted on let-7b and miR-199a, was constructed. B16F10 cells were divided into seven groups: control group, let-7b plasmid group, miR-199a plasmid group, empty plasmid group, let-7b inhibitor group, miR-199a inhibitor group, inhibitor control group. Foreign gene was transfected into B16F10 cells, let-7b and miR-199a expression were validated from RNA level, protein level and cell level. Results The relative let-7b or miR-199a gene expression of the let-7b plasmid group (3.8776±0.1372)and miR-199a plasmid group (2.8660±0.2821)were significantly higher than control group (P＜0.05), the relative let-7b or miR-199a gene expression of the let-7b inhibitor group (0.2057±0.0263) and miR-199a inhibitor group(0.2656±0.0253) were significantly lower than control group(P＜0.05). The cyclinD1 expression of the let-7b plasmid group(2.023±0.315) and let-7b inhibitor group (1.857±0.377) were significantly higher than control group (0.997±0.041) (P＜0.05), whereas, the Met expression of themiR-199a plasmid group (5.19±0.309) and miR-199a inhibitor group (4.87±0.044) were significantly higher than control group (2.2±0.198) (P＜0.05). The let-7b plasmid group and miR-199a plasmid group B16F10 cell growth rate were slower than control group, especially on the third day after transfection, the growth rate gradually dropped to the lowest value (P＜0.05). In addition, the apoptosis rates of the let-7b plasmid group and miR-199a plasmid group reach to (11.8±1.19)% and (11.3±1.59)%,which were significantly higher than control group (P＜0.05). Conclusions let-7b and miR-199a may be a negative regulator on the B16F10 cell growth and proliferation.