Effect of baicalin on expression of fibrogenic factors TGF-β1, mmp2 and timp2 in tissue of mice with pulmonary fibrosis / 中国中药杂志

To investigate the effect of baicalin extracted from Qinbai Qingfei Concentrated Pills on the expressions of TGF-β1, mmp2 and timp2 in mice with pulmonary fibrosis induced by bleomycin. The Biacore technique was used to detect the specific binding between Qinbai Qingfei Concentrated Pills and TGF-β1, and the affinity components were enriched, regenerated and recovered by Biacore fishing. Then ultra-performance liquid chromatography and quadrupole time of flight mass spectrometry(UPLC-Q-TOF-MS) were used to determine whether the monomer was baicalin. Biacore was used to verify the affinity kinetics of baicalin, which was validated by pharmacodynamics in vivo. Totally 30 BALB/C mice were randomly divided into three groups: baicalin group, blank group and model group. The blank group was given sodium chloride injection(0.08 mL·kg~(-1)), while the model group and the baicalin group were injected with 4 mg·kg~(-1) bleomycin. The localization of TGF-β1, mmp2 and timp2 protein in the cells and the mRNA expressions of TGF-β1, mmp2 and timp2 were detected by RT-PCR 14 days later. The results of Biacore affinity analysis showed that the peak of binding response between Qinbai Qingfei Concentrated Pills and TGF-β1 protein reached 1 524.0 RU, with specific binding. The affinity constant K_D of baicalin and TGF-β1 was 1.620 06 μmol·L~(-1), which was determined by SPR kinetic analysis, suggesting a stable binding between baicalin and TGF-β1, which verified the results of angulation. The results of immunohistochemistry showed that the deposition of cellulose in baicalin group was significantly less than that in model group, the mRNA expressions of TGF-β1, mmp2 and timp2 were decreased in baicalin solution compared with the model group. Baicalin combined with TGF-β1 could inhibit the expressions of mmp2 and timp2 and delay the progress of pulmonary fibrosis.

Effect of Dilong on expression of fibrogenic factors TGF-β1 and α-SMA in lung tissue of mice with pulmonary fibrosis / 中国中药杂志

The aim of this paper was to investigate the effect of Dilong( geosaurus) on the expressions of fibrotic factors TGF-β1 and α-SMA in bleomycin-induced pulmonary fibrosis mice. The binding ability of Dilong to fibrotic factor TGF-β1 was initially detected by Biacore technology and verified by in vivo pharmacodynamics. A total of 60 SPF C57 mice were randomly divided into 6 groups. Except the blank group( injecting 0. 08 m L·kg-1 sodium chloride in the trachea),the other five groups were given bleomycin( 4 mg·kg-1) to replicate the pulmonary fibrosis model. After 14 days of drug treatment,the expressions of TGF-β1 and α-SMA were detected by Masson staining,immunohistochemistry and RT-PCR. The results of Biacore experiment showed that the extract of Dilong was well bound to TGF-β1 protein in vitro,and the binding value reached 619. 3. Compared with the model group,Masson's results showed that cellulose deposition in high-dose,medium-dose and low-dose Dilong groups decreased to varying degrees. RT-PCR results showed that different doses of Dilong could reduce protein and mRNA expressions of TGF-β1 and α-SMA to a certain extent in a dose-dependent manner. In conclusion,Dilong could delay the process of pulmonary fibrosis by binding to target protein TGF-β1 and inhibiting the expression of α-SMA.

Assessment of molecular recognition element for the quantification of human epidermal growth factor using surface plasmon resonance

Background: A method for the selection of suitable molecular recognition element (MRE) for the quantification of human epidermal growth factor (hEGF) using surface plasmon resonance (SPR) is presented. Two types of hEGF antibody, monoclonal and polyclonal, were immobilized on the surface of chip and validated for its characteristics and performance in the quantification of hEGF. Validation of this analytical procedure was to demonstrate the stability and suitability of antibody for the quantification of target protein. Results: Specificity, accuracy and precision for all samples were within acceptable limit for both antibodies. The affinity and kinetic constant of antibodies-hEGF binding were evaluated using a 1:1 Langmuir interaction model. The model fitted well to all binding responses simultaneously. Polyclonal antibody (pAb) has better affinity (K D = 7.39e-10 M) than monoclonal antibody (mAb) (K D = 9.54e-9 M). Further evaluation of kinetic constant demonstrated that pAb has faster reaction rate during sample injection, slower dissociation rate during buffer injection and higher level of saturation state than mAb. Besides, pAb has longer shelf life and greater number of cycle run. Conclusions: Thus, pAb was more suitable to be used as a stable MRE for further quantification works from the consideration of kinetic, binding rate and shelf life assessment.

The Influence of PEG Modification on EGF-PLL Binding Capacities to EGFR / 生物化学与生物物理进展

Cationic polymers are being developed quickly as gene delivery vectors. For in vivo gene delivery, the cationic polymers are usually further modified by hydrophilic polymer grafting or ligand conjugation, which have been shown to increase the vector stability, gene delivery efficiency and specificity greatly. Some previous research had shown that modified hydrophilic polymer may partly shield the targeting ligand and result in poor delivery specificity. Developing a method to evaluate the influence of PEG modification on targeting delivery is particularly critical to cationic polymer design and gene therapy development. One of most commonly used cationic polymer polylysine (PLL) was chosen as a model. Targeting ligand epidermal growth factor(EGF)was conjugated with PLL to form PLL-EGF. Then hydrophilic polymer polyethylene glycol (PEG) with molecular mass 7 000 and 20 000 were used to modify PLL-EGF respectively to generate PEG7000-g-PLL-EGF and PEG20000-g-PLL-EGF. In BIAcore experiments, epidermal growth factor receptor (EGFR) was conjugated onto BIAcore chip and various PEG modified PLL-EGF solutions were flowed over the chip. By observing the change of RU value, the specific interaction of EGF to EGFR was compared. Compared with PLL-EGF, PEG modified PLL-EGF showed lower association rate and higher disassociation rate to EGFR. Furthermore, compared to PEG7000 modified PLL-EGF, PEG20000 modified PLL-EGF got lower association rate and higher disassociation rate to EGFR. The Scatchard analysis results showed that the interactions between EGFR and PLL-EGF or PEG-PLL-EGF are non-linear. It can be concluded that PEG modification indeed reduced the association rate and enhanced the dissociation rate of EGF to EGFR. The length of PEG chain was also a key factor to influence interaction between ligand and receptor. The results showed that it was critical important to evaluate the influence of PEG modification on delivery specificities. The BIAcore method developed in this paper can successfully evaluate the influence, which would be important for cationic polymer design and its application as potential non-viral gene delivery vectors.