Dagong Sun

Acute dichlorvos poisoning induces hemorheological abnormalities in rabbits via oxidative stress

Dichlorvos is an important insecticide used largely. Some studies have demonstrated that organophosphate pesticide has effects on erythrocyte membrane structures, which is critical to erythrocyte function and hemorheology. The aim of the present study was to explore the effect of oxidative stress on hemorheological changes during dichlorvos poisoning in rabbits. Data indicated that after dichlorvos exposure the hematocrit adjusted viscosity at high shear rate increased and erythrocyte membrane fluidity decreased. Data obtained from plasma showed that lipid peroxidative substance-malonaldehyde was elevated and superoxide dismutase was reduced. In summary, oxidative stress does occur in dichlorvos poisoning and may lead to hemorheological alterations. The changes of hemorheology may be responsible for the pathophysiology of the dichlorvos poisoning.

The effects of non-ionic contrast medium on the hemorheology in vitro and in vivo.

Contrast media are the commonly used agents in radiology. However, because of their characteristics of high osmolality, high viscosity, and chemical toxicity, the administrations of contrast media have been shown to cause adverse effects especially on hemorheology in short time course. The present study is to find the effects of a non-ionic contrast medium, iopromide, on the hemorheology in long time course both in vitro and in vivo. For in vitro treatment, human peripheral blood samples were incubated with contrast medium at 37°C for 0.5, 1 and 2 h. For in vivo study, about 15 ml of contrast medium was injected into rabbits and blood samples were collected at 0.5, 2, 6, and 24 h after the bolus injection. Hemorheological parameters were examined. Results showed that hematocrit adjusted whole blood viscosity increased significantly at 1 h after in vitro treatment of contrast medium, while it decreased at 0.5 h and remained low till 6 h after bolus injection. Ektacytometer showed that erythrocyte deformability decreased to the lowest level at 2 h in vitro and it dropped at 0.5 h and resumed to normal after 2 h in vivo. Erythrocyte small deformation indices were reduced by contrast medium in both in vitro and in vivo studies. Erythrocyte orientation index was also reduced in in vivo study. Erythrocyte electrophoresis rates at all time points decreased but osmotic fragility did not change in both studies. These impaired hemorheological parameters may disturb the microcirculation and cause adverse effects in patients with kidney diseases.

Biorheological changes of dendritic cells at the different differentiation stages

The differentiation, maturation and functioning of Dendritic cells (DCs) are dynamic processes. This study investigated the changes of DCs migration ability and biorheological properties during their differentiation. Transmigration assay showed that, DCs migration rate was improved significantly as they differentiate (p < 0.05); NSC (Rac1 blocker) treatment could significantly decrease their migration rates (p < 0.05). Confocal images showed that, F-actin uniformly distributed in monocytes; with DCs differentiation, F-actin began to remodel and gather at the site of dendrites; the images presented surface ruffles and uneven sawtooth-like cytoskeletal structures. Fluorescence polarization analysis showed that, membrane fluidity was increased significantly with DCs differentiation (p < 0.05). CD62L was upregulated significantly (p < 0.05) on the third and ninth days. CD2 was upregulated significantly (p < 0.05) until the seventh day. DCs electrophoretic mobility was increased continuously, especially increased significantly from the third day to the fifth day and the final stage (p < 0.05). These results indicate that there are significant changes in the biorheological properties of DCs during their differentiation.