[Influence of high-voltage electrical burn on the rheological property of platelet and leukocyte in rats and the interventional effect of pentoxifylline]

To investigate the influence of high-voltage electrical burn (HEB) on the aggregation and adhesion of platelet and leukocyte in rats and the interventional effect of pentoxifylline (PTX).One hundred and eighty SD rats were divided into control, electrical burn (EB), and pentoxifylline treatment (PT) groups according to the random number table, with 60 rats in each group. (1) Ten rats were taken from each group at 15 minutes before injury for the observation of the microcirculatory perfusion of chest skin with Laser Doppler Perfusion Imager (LDPI), and the number of leukocyte adherent to mesenteric venule with Bradford Variable Projection Microscope (BVPM). Serum was collected from heart blood to determine the contents of platelet activating factor (PAF), thromboxane B2 (TXB2), prostacyclin (PGI2), P-selectin, E-selectin and L-selectin by double-antibody sandwich enzyme-linked immunosorbent assay. The ratio of TXB2 to PGI2 was calculated therefrom. (2) Model of HEB was reproduced in the remaining 50 rats of EB group and that of PT group with voltage regulator and experimental transformer (the electrical current applied to the left forelimb and exited from the right hind limb). The remaining 50 rats of control group were sham injured with the same devices without electric current. Within 2 minutes post injury (PIM), rats in control group and EB group were intraperitoneally injected with 2 mL isotonic saline, while rats in PT group were intraperitoneally injected with 2 mL pentoxifylline (50 mg/mL). At PIM 5 and 1, 2, 4, 8 hour(s) post injury (PIH), 10 rats of every group were randomly chosen at each time point for the observation of the microcirculatory perfusion of chest skin and the number of leukocytes adherent to mesenteric venule through the same method as used above, and the levels of the related factors of aggregation and adhesion of platelets and leukocytes were determined, and then the relative ratio was calculated. Data were processed with the analysis of variance of factorial design and LSD test.The contents of PAF, TXB2, PGI2, P-selectin, E-selectin, L-selectin, and the ratio of TXB2 to PGI2, as well as the number of adhered leukocyte in EB group were higher, while the microcirculatory perfusion value was lower than those of control group, with F values from 854.20 to 8156.52, P values all below 0.01. The microcirculatory perfusion value and PGI2 content of PT group were higher, while the contents or number of other indexes were lower than those of EB group, with F values from 33.18 to 1033.99, P values all below 0.01. Only the data within EB group and PT group were comparable. The contents of PAF, TXB2, PGI2, P-selectin, E-selectin, L-selectin, and the ratio of TXB2 to PGI2, as well as the number of adhered leukocyte in EB group and PT group at each time point were significantly higher than those at 15 minutes before injury, while the microcirculation perfusion value was significantly lower than that at 15 minutes before injury (P values all below 0.001), with the exception of the ratio of TXB2 to PGI2 in PT group and E-selectin in EB group and PT group at PIM 5. The contents of PAF, TXB2, and E-selectin and the ratio of TXB2 to PGI2 in EB group peaked at PIH 4, and they were respectively (9.3 ± 0.9) ng/mL, (14.31 ± 0.65) nmol/mL, (271.2 ± 18.4) ng/mL and 4.62 ± 0.26. The contents of PGI2 and P-selectin, and the number of adhered leukocyte in EB group peaked at PIH 8, and they were respectively (3.98 ± 0.24) nmol/mL, (514 ± 24) ng/mL, and (25.50 ± 4.14) per 100 µm venule. The content of L-selectin peaked at PIH 2 [(876 ± 54) ng/mL]. The microcirculatory perfusion value was lowest at PIM 5 [(1.17 ± 0.10) V].HEB can increase the contents of PAF, TXB2, PGI2, P-selectin, E-selectin, L-selectin, the ratio of TXB2 to PGI2, and the number of adhered leukocyte, as well as decrease the skin microcirculatory perfusion value. PTX can inhibit the aggregation and adhesion of platelets and leukocytes through increasing the content of PGI2 and decreasing contents of other factors mentioned above, thus alleviating the microcirculatory dysfunction after HEB.