No abstract

The insecticide acetamiprid is used to control noxious agricultural pests. However, it can cause mammalian toxicity. We evaluated the reproductive toxicity of acetamiprid in adult male Sprague Dawley rats. Rats were given oral acetamiprid alone or with vitamin E for 35 days. Rat plasma testosterone concentration and sperm quality decreased significantly as the levels of luteinizing hormone (LH) increased after exposure. At the same time, acetamiprid increased malondialdehyde and nitric oxide (NO) levels of Leydig cells. Further analysis showed that acetamiprid reduced the adenosine triphosphate (ATP) and cyclic adenosine monophosphate (cAMP) production of Leydig cells, but the expression of luteinizing hormone/choriogonadotropin receptor (LHCGR) and the activity of adenylyl cyclase were not changed. Acetamiprid exposure also significantly diminished protein levels of steroidogenic acute regulatory protein (STAR), hydroxy-delta-5-steroid dehydrogenase, 3 beta- and steroid delta-isomerase cluster (HSD3B), and cytochrome P450, family 11, subfamily a, polypeptide 1 (CYP11A1), and testicular mRNA levels, which are cAMP-dependent proteins that are essential for steroidogenesis. Electron microscopy indicated mitochondrial membrane damage in the Leydig cells of the testes of exposed rats. Vitamin E ameliorated the impairment of acetamiprid on Leydig cells. Our results indicate that acetamiprid causes oxidative stress and mitochondrial damage in Leydig cells and inhibits the synthesis of testicular ATP and cAMP. Acetamiprid disrupts subsequent testosterone biosynthesis by decreasing the rate of conversion of cholesterol to testosterone and by preventing cholesterol from entering the mitochondria within the Leydig cells. These effects caused reproductive damage to the rats.

Aspongopus chinensis Dallas is used as a traditional Chinese medicine. In China, clinical evidence suggests that it has anticancer activity. However, the anticancer active components are not fully elucidated. In the present study, we purified an anticancer active component (named CHP) from A. chinensis. To gain a comprehensive insight into the protein components, shotgun proteomic analysis was conducted. The anticancer active protein band was cut from the sodium dodecyl sulphate-polyacrylamide gel electrophoresis gel and digested with trypsin to generate peptide mixture. The peptide fragments were then analysed by liquid chromatography tandem mass spectrometry; 18 proteins were identified. In addition, we evaluated the effects of CHP on the proliferation and apoptosis of two human gastric cancer cell lines (SGC-7901 and BGC-823). The cultured cells were treated with CHP at concentrations of 20, 30, and 40 μg/mL. Inhibition of cell growth was determined by the MTT assay. Hoechst 33258 staining was adopted to detect apoptosis morphologically. Apoptotic cells were quantified by Annexin V-FITC/propidium iodide staining and flow cytometry. Tumour growth was assessed by subcutaneous inoculation of 4T1 cells into BALB/c mice. There was a concentration- and time-dependent decrease in the proliferation of both cell lines at CHP concentrations of 20–40 μg/mL. Apoptotic characteristics, such as karyopyknotic pyknic hyperfluorescence bolus and nuclear fragmentation, were observed in both the cell lines by Hoechst 33258 staining. Flow cytometry showed that CHP induced significant (P < 0.01) concentration-dependent apoptosis of SGC-7901 cells. In vivo assay showed that CHP can partially inhibit tumour growth derived from 4T1 cells in vivo. The present study is the first to report that CHP in A. chinensis inhibits the proliferation of cancer cell lines via the suppression of cancer cell proliferation and acceleration of apoptosis.

Natural products from insects can be potent sources for developing a variety of pharmaceutical products. Aspongopus chinensis Dallas has been used as a traditional Chinese medicine and there are several clinical evidences to support its anticancer activity. However, the anticancer active ingredients present in A. chinensis remain unidentified. In the present study, we investigated the anticancer effects of a methanol extract of A. chinensis (AME). Gas chromatography mass spectrometry was used to analyse the chemical composition of AME. The cell viability of MDA-MB-453 and HCC-1937 cells treated with different concentrations of AME was detected by MTT assay and the ratio of cells in different cell cycle phases was analysed by flow cytometry. The expression of genes associated with cell cycle was analysed by real-time PCR assay. The results showed that oleic acid (25.39%) and palmitic acid (21.798%) are the main anticancer compounds present in AME. There was a concentration-dependent decrease in the proliferation of MDA-MB-453 and HCC-1937 cells. Moreover, treatment with AME induced a S-phase arrest in the cells. Real-time PCR assay demonstrated that AME could significantly downregulate the expression of CDC20, AURKB, PLK1, CCNB2, and TOP2A mRNAs and upregulate the expression of GADD45A mRNA. We demonstrate that the methanol extract of A. chinensis could be a potential natural alternative or complementary therapy for breast cancer.