ABSTRACT
Objective To investigate the distribution and density of Culex mosquito populations and the resistance of Culex pipiens pallens to insecticides in Jiangsu Province in 2018 and 2019. Methods During the period from June to October in 2018 and 2019, six counties (districts, cities) were sampled in southern, northern and central Jiangsu Province as surveillance sites. The density of Culex mosquitoes was measured overnight using the light trapping technique. In addition, Culex pipiens pallens mosquitoes were collected from Hai’an of Nantong City and Yandu District of Yancheng City, central Jiangsu Province, and the sensitivity of female first filial generations to dichlorodiphenyltrichloroethane (DDT), malation, proposur, beta cypermethrin and deltamethrin was tested using the standard WHO insecticide susceptibility test assay. Results A total of 104 423 Culex mosquitoes were captured in six surveillance sites of Jiangsu Province in 2018 and 2019, and Culex quinquefasciatus (49.11%), Culex pipiens pallens (28.38%), and Culex tritaeniorhynchus (21.04%) were predominant species. The density of Culex mosquitoes started to increase since early June, peaked in July and tended to be low in late October. Culex pipiens pallens mosquitoes captured from Hai’an was susceptible to malation, while those from Yandu District were moderately resistant to malation. Culex pipiens pallens mosquitoes from both Yandu and Hai’an were moderately resistant to proposur, and were resistant to DDT, beta cypermethrin and deltamethrin. Conclusions Culex quinquefasciatus, Culex pipiens pallens and Culex tritaeniorhynchus are predominant Culex species in Jiangsu Province. Culex pipiens pallens is resistant to DT, beta cypermethrin and deltamethrin in central Jiangsu Province.
ABSTRACT
Objective To analyze the changes of small molecular metabolites in the larvae of a deltamethrin-sensitive strain of Anopheles sinensis following exposure to deltamethrin, so as to provide the scientific basis for investigating the metabolic pathway and screening metabolic markers of deltamethrin in An. sinensis. Methods The 50% and 75% lethal concentrations (LC50 and LC75) of deltamethrin against the larvae of a deltamethrin-sensitive strain of An. sinensis were calculated in laboratory. The type and content of An. sinensis larvae metabolites were detected using high performance liquid chromatography and mass spectrometry (LC-MS/MS) following exposure to deltamethrin at LC50 and LC75 for 30 min and 24 h, and the changes of metabolites were analyzed. Results The LC50 and LC75 values of deltamethrin were 4.36 × 10-3 µg/mL and 1.12 × 10-2 µg/mL against thelarvae of a deltamethrin-sensitive strain of An. sinensis. Following exposure of the larvae of a deltamethrin-sensitive strain of An. sinensis to deltamethrin at LC50 and LC75 for 30 min, the differential metabolites mainly included organic oxygen compounds, carboxylic acid and its derivatives, fatty acyl and pyrimidine nucleotides, with reduced glucose levels. Following exposure for 24 h, the differential metabolites mainly included organic oxygen compounds, carboxylic acid and its derivatives, aliphatic acyl and purine nucleotides, with increased glucose level detected. Conclusion Carbohydrate, carboxylic acid and its derivatives, fatty acyls, amino acids and their derivatives may play important roles in deltamethrin metabolism in the larvae of a deltamethrin-sensitive strain of An. sinensis.
ABSTRACT
Objective To explore the neuroprotective effect and mechanism of picroside II on p38 mitogen activated protein kinase (p38 MAPK) signal transduction pathway after cerebral ischemia/reperfusion injury in rats. Methods A total of 150 healthy male Wistar rats were subject to establish middle cerebral artery occlusion/reperfusion (MCAO/R) models by inserting a monofilament thread. All rats were randomly divided into sham group, model group, picroside (Pier) group, anisomycin (Anis, agonist of p38 MAPK) group, Anis+Picr group, SB203580 (SB, inhibitor of p38 MAPK) group and SB+Picr group. The neurobehavioral function was evaluated by modified neurological severity score points (mNSS) test. The structure of neuron was observed using HE staining. The apoptotic cells were counted using TUNEL assay. The expression of phosphorylated p38 MAPK (p-p38 MAPK) in cortex was determined using the immunohistochemistry. And the expressions of p-p38 MAPK, phosphorylated MAPK activated protein kinase-2 (p-MK2), phosphorylated cytoplasm phospholipase A2 (p-cPLA2), interleukin-6 (IL-6) and tumor necrotic factor a (TNF-α) were determined by Western blotting. Results No neurological behavioral malfunction was found in sham group. In model group, the damage of neuron was worsened, while the neurobehavioral function score, apoptotic cell index and the expressions of p-p38 MAPK, p-MK2, p-cPLA2,IL-6 and TNF-α increased significantly than those in control group. No significant difference was found in TNF-α. In Pier group, SB group and SB+Picr group, the damage of neuron was lighter, the neurological behavioral function was improved, the number of apoptotic cells and the expressions of p-p38 MAPK, p- MK2, p-cPLA2 and IL-6 decreased significantly than those in model group. In Anis group and Anis + Pier group, the damage was worsen, the cerebral infarction was larger, and the expressions of p-p38 MAPK, p-MK2, p-cPLA2 and IL-6 increased significantly than those in control group. Conclusion Picroside II can protect the neuron from the apoptosis and inflammation reaction after MCAO/R by inhibiting p38 MAPK signal transduction pathway in rats.