Objective To explore the effects of different methods of antigen retrieval on the results of immunohistochemical staining of nuclear receptors. Methods Antigens were retrieved by using microwave oven, autoclave, enzyme and autoclave plus enzyme, respectively, in liver sections from DA.1U rats, followed by immunohistochemical staining. Results After antigen retrieval with autoclave, the positive staining intensity of nuclear receptors LXR-α, LXR-β, PPAR-γ and FXR in the liver sections from DA.1U rats was enhanced obviously, and the location of nuclear receptors was better by using this method than the others. Conclusion In the immunohistochemical staining of nuclear receptors, using autoclave to retrieve antigens is the best method.

The Chinese herbal medicine Tianma (Gastrodia elata) has been used for treating and preventing primary headache over thousands of years, but the exact pharmacological mechanism of the main bioactive ingredient gastrodin remains unclear. In present study, the effects of gastrodin on calcitonin gene-related peptide (CGRP) and phosphorylated extracellular signal-regulated kinase1/2 (pERK1/2) expression were observed in rat trigeminal ganglion (TG) after in vitro organ culture to explore the underlying intracellular mechanism of gastrodin on primary vascular-associated headache. CGRP-immunoreactivity (CGRP-ir) positive neurons count, positive area, mean optical density and integrated optical density by means of immunohistochemistry stain were compared at different concentrations of gastrodin, which was separately co-incubated with DMEM in SD rat TG for 24 hours. Only at 5 or 10 mmol L(-1) concentration, gastrodin demonstrated significantly concentration-dependent reduction of CGRP-ir (+) expression and its action closed to 1.2 mmol L(-1) sumatriptan succinate. While at 2.5, 20, and 40 mmol L(-1) concentration, gastrodin did not show remarkable effects on CGRP-ir (+) expression. The optimal concentration of gastrodin (5 and 10 mmol L(-1)) similarly inhibited CGRP-mRNA expression level separately compared with 1.2 mmol L(-1) sumatriptan succinate and 10 micromol L(-1) flunarizine hydrochloride, which was quantitatively analyzed by real-time PCR (RT-PCR). pERK1/2 level was examined by Western blotting after co-cultured with optimal concentration of gastrodin and effective specific ERK1/2 pathway inhibitors PD98059, U0126. The result indicated that gastrodin significantly reduced pERK1/2 protein actions similarly to ERK1/2 pathway specific blockade. It suggests ERK1/2 signaling transduction pathway may be involved in gastrodin intracellular mechanism. This study indicates gastrodin (5 and 10 mmol L(-1)) can remarkably reduce CGRP-ir (+) neuron, CGRP-mRNA and pERK1/2 expression level in cultured rat TG, with its actions similar to the effective concentration of sumatriptan succinate, flunarizine hydrochloride and specific ERK1/2 pathway blocker. The intracellular signaling transduction ERK1/2 pathway may be involved in the gastrodin reducing CGRP up-regulation in rat TG after organ culture.

Objective To evaluate the feasibility of real-time quantitative PCR (RtPCR) with small volume regarding the stability, efficiency and reliability of amplification, and determine the optimal quantity of cDNA template suitable for small PCR volume. Methods The experiment was carried out in 3 groups with 10, 15 and 20μL reaction volume, respectively. In each group, rat β-actin mRNA was detected by RtPCR with 0.1, 0.2, 0.3 or 0.4μL rat cDNA as template, respectively. The amplification curve and melting curve were used to evaluate the reaction stability. The fitting of a curve of gradient templates against threshold cycle numbers was to show the reaction efficiency and the linear correlativity was to estimate the suitability of the template quantity. In addition, in order to estimate reliability, pristane-induced arthritis (PIA) rat model was established, and spleen TNF-α mRNA expression was detected by RtPCR with the selected reaction volumes. Results The amplification of rat β-actin mRNA was specific and stable in 10μL, 15μL and 20μL PCR volume, and had a high efficiency. Furthermore, the standard curves fitted by 0.1-0.4μL gradient templates showed a significant linear correlation in each volume group. When the 10μL and 20μL PCR volumes, and 0.2μL cDNA templates were chosen, the TNF-α mRNA expression in PIA rat spleen showed significant upregulation in both two volume groups as anticipated. Conclusion The experiment shows that it is feasible in the RtPCR amplification to use the small reaction volume of 10μL and 15μL, which has good stability and reliability. And 0.1-0.4μL templates are all suitable for the reaction system. PCR with small volume can not only save the reagents and template, especially rare clinical specimens, but also is helpful for the realization of high-throughput reaction.