RESUMO
Near-infrared spectroscopy (NIRS) combined with chemometrics can achieve rapid detection in process analysis. After variable selection, the redundant information is effectively removed and the characteristic variables related to the response values are selected. Compared with global model, the complexity is significantly reduced and the prediction accuracy is also improved. In this study, near-infrared spectroscopy analysis combined with different variable selection methods was applied to achieve the rapid detection of baicalin in the extraction process of Scutellaria baicalensis. Data sets were divided based on sample set portioning based on joint x-y distance (SPXY) method. Competitive adaptive weighted resampling method (CARS), random frog (RF) and successive projections algorithm (SPA) were applied to variable selection. Partial least squares (PLS) models were constructed based on above three methods, and the prediction results were compared. After CARS, RF and SPA method, 92, 10 and 17 variables were screened out respectively. According to the performance of the models, CARS method is found to be more effective and suitable than RF and SPA. Furthermore, the characteristic variables selected by CARS method have a better correspondence with the chemical structure of baicalin. The root mean square error (RMSEC) of the calibration set and the root mean square error (RMSEP) of the prediction set are 0.528 2 and 0.720 2 respectively. Compared with the global PLS model, the correlation coefficient of the calibration set (Rc) is increased to 0.979 9 from 0.917 0, and the relative standard errors of prediction (RSEP) is reduced to 5.59% from 10.58%.
RESUMO
The aim of this paper was to investigate the preventive effects of Keluoxin Capsules(KLX) on diabetic retinopathy in db/db mice. One hundred male db/db diabetic mice(45-55 g, 8 weeks) were randomly divided into 5 groups(model, KLX low dose, KLX middle dose, KLX high dose, Dobesilate) and 20 male C57 BL/KsJdb~(+/+) were taken as control group. Body weight and fasting blood-glucose were detected every week. Mice were administrated with saline(control and model group), KLX(780, 1 560, 3 120 mg·kg~(-1)·d~(-1), ig), Dobesilate(195 mg·kg~(-1)·d~(-1), ig) for 20 weeks, respectively. At the end of the administration, optical coherence tomography, fundus fluorescein angiography and electroretinogram of the retina were measured. The eyeball was extirpated and retina was isolated to make paraffin section, followed by HE staining and glial fibrillary acidic protein(GFAP) immunohistochemistry. The results indicated that KLX has no obvious effect on body weight and fasting blood level in db/db mice. However, KLX could significantly regulate the thickness of retinal ganglion layer and inner plexiform layer. KLX was able to remarkably reduce the quantity of diabetic microvessel. Meanwhile, KLX could notably improve retinal function. Moreover, KLX could observably modulate the cell arrangement and edema in each layer. There was no markable difference in retina according to the immunochemistry assay. In the present study, KLX exert marked preventive effects on diabetic retinopathy in db/db mice, which provided an experimental evidence for clinical use.