Effect of local injection of recombinant hirudin on survival of skin flaps with venous congestion in a rabbit model / 中华烧伤杂志

<p><b>OBJECTIVE</b>To observe the effect of local injection of recombinant hirudin on survival of skin flaps with venous congestion in a rabbit model.</p><p><b>METHODS</b>Eighteen healthy rabbits were enrolled and divided into heparin-treatment (HT), recombinant hirudin treatment (RHT) and control (C) groups according to the random number table, with 6 rabbits in each group. After intravenous anesthesia with 20 g/L pentobarbital sodium, model of skin flaps with venous congestion in the size of 6 cm × 3 cm was reproduced in the dorsal side of left ear of each rabbit, in which central artery of ear served as the only blood supply, and a pedicle of 1 cm in width including central vessel of ear and its accompanying nerves as the only venous return pathway. Each flap in RHT, HT, C groups was respectively given 1 mL recombinant hirudin (1 U), low-molecular-weight heparin (625 U), and isotonic saline via multi-point and homogenous injection, then they were sutured in site. Appearance and survival rate of the flaps were observed after operation. Specimens of the distal part of flaps were harvested for determination of thromboxane B2 (TXB2) on post operation day (POD) 1, 3, 5, 7. Data were processed with one-way analysis of variance and t test.</p><p><b>RESULTS</b>Rabbit model of skin flaps with venous congestion was reproduced successfully. Obvious hair loss was observed in completely necrotic parts of flap in each group. Obvious edema was observed in all flaps with venous congestion at distal site. The color of flaps in HT and RHT groups were lighter as compared with that in C group, and apparent hematoma of flap was observed in 1 rabbit of RHT group, 2 rabbits of HT group, 4 rabbits of C group on POD 1. The survival rate of flap in HT and RHT groups was respectively (92.3 ± 1.7)% and (94.8 ± 1.9)%, both higher than that in C group [(77.9 ± 1.2)%, F = 191.29, P < 0.05]. There was no statistical difference in survival rate of flap between HT group and RHT group (t = 2.75,P > 0.05). The content of TXB2 in HT and RHT groups on POD 3, 5 was respectively lower than that in C group (with t value from 6.68 to 30.55, P values all below 0.01), but there was no statistical difference between HT and RHT groups (with t value respectively 1.22, 6.44, P values all above 0.05).</p><p><b>CONCLUSIONS</b>Local injection of low-molecular-weight heparin or recombinant hirudin can significantly ameliorate venous congestion of skin flap in rabbit ear, and improve its survival rate.</p>

Influence of serum from rats with scald on the cytoskeleton of colonic smooth muscle cells of rats / 中华烧伤杂志

<p><b>OBJECTIVE</b>To study the influence of serum from scalded rats on the cytoskeleton of colonic smooth muscle cells (CSMC) of rats cultured in vitro, and to probe the possible mechanism of gastrointestinal motility disorder after burn.</p><p><b>METHODS</b>CSMC isolated from healthy adult Wistar rat were cultured and divided into scald serum group (SS) and normal serum group (NS) according to the random number talbi. Two normal Wistar rats were used, one of which was inflicted with deep partial-thickness scald. Serum was obtained from blood collected from these two rats respectively and diluted to 20% in concentration. Serum from scald and normal rats were respectively added to the culture of CSMC in SS and NS groups. The expression of actin and the relative content of β-tubulin in CSMC was respectively determined with flow cytometry and Western blot at post treatment hour (PTH) 1, 3, 6, and 12 (with 10 samples in each group at each time point). Data were processed with t test.</p><p><b>RESULTS</b>Fluorescence intensity of actin in SS group at PTH 1, 3, 6, and 12 was respectively 59 ± 4, 26 ± 6, 39 ± 6, and 42 ± 6, all significantly lower than those in NS group (95 ± 10, 91 ± 10, 102 ± 9, and 97 ± 9, with t value respectively 10.528, 18.069, 18.748, 16.647, P < 0.05 or P < 0.01). In SS group, the fluorescence intensity decreased to the nadir at PTH 3, and then increased persistently at PTH 6 and 12. (2) Relative content of β-tubulin in SS group at PTH 1, 3, 6, and 12 was respectively 14.44 ± 0.26, 8.61 ± 0.19, 11.76 ± 0.31, and 12.13 ± 0.29, all significantly less than those in NS group (22.37 ± 1.15, 21.87 ± 1.79, 23.24 ± 1.55, and 21.99 ± 2.02, with t value respectively 21.176, 23.365, 23.000, 15.273, P values all below 0.01). In SS group, the relative content of β-tubulin decreased to the nadir at PTH 3 and increased slowly at PTH 6 and 12.</p><p><b>CONCLUSIONS</b>The reduction of CMSC content which has the tendency of increasing later, can be attributed to the influence of scald serum in initial stage. This may be related to the tolerance and adaptation to scald serum and self-repair of CMSC.</p>

Influence of lipopolysaccharide and burn sera on ion channels in smooth muscle cells of colon of guinea pig / 中华烧伤杂志

<p><b>OBJECTIVE</b>To investigate the influence of lipopolysaccharide (LPS) and burn sera on potassium channels (Kca) in smooth muscle cells of colon of guinea pig so as to elucidate the molecular mechanism of gastrointestinal motility dysfunction after severe burns.</p><p><b>METHODS</b>Single smooth muscle cells were isolated from the taenia coli of guinea pig with enzyme digestion. The standard patch clamp technique was employed to record the single KCa channel currents of smooth muscle cell after challenged by LPS and burn serum. Data were recorded and analyzed by P clamp 6.04 software, and the probability of open (PO), mean open time (OT), mean close time (CT) and current amplitude (CA) were determined. Subsequently, LPS in the concentration of 20, 40, 60, 80 and 100 mg/L, respectively, and normal serum and burn serum in the concentration of 10% were respectively added into medium to examine the influence of the two clamps and sera on the KCa activity.</p><p><b>RESULTS</b>In hyperkalemic solution, the KCa conductance of colonic smooth muscle cells of the guinea pig was (271 +/- 7) pS, indicating it was an ionic channel with high conductivity. Subsequent to depolarization of the membrane, inner-cellular calcium level was increased, and channel PO was also increased, which could be blocked by 1 mmol/L tetraethylammonium (TEA) outside the membrane chaff. As 40 mmol/L TEA inside the membrane chaff did not show such effect, it was proved to be KCa current. The activity of the channel as determined with two kinds of clamps was increased in a dose dependent manner with LPS challenge when the concentration of calcium was 0 mol/L. The KCa activity and PO of the channel was increased obviously when the concentration of LPS was above 40 mg/L (P < 0.05 or 0.01), and it could not be reversed after irrigation with non-LPS medium. By using the two kinds of patch clamps, the KCa were activated by burn sera, but not normal sera.</p><p><b>CONCLUSION</b>Both LPS and burn sera can lead to inhibition of the gastrointestinal motility by activation of KCa channels.</p>

Influence of scald on the cytoskeleton of colonic smooth muscle cells of the rats / 中华烧伤杂志

<p><b>OBJECTIVE</b>To investigate the changes in the morphology and cytoskeleton (CSL) content of the CSL in the colonic smooth muscle cells (SMCs) of rats in early postscald stage, so as to elucidate the mechanism of dysfunction of gastrointestinal motility.</p><p><b>METHODS</b>Seventy Wistar rats were randomly divided into normal control (n = 10, without scald) , and scald ( n = 60, with 10 cm x 7 cm wound inflicted on the back) groups. The colonic smooth muscle tissue of 10 normal rats and scalded rats were harvested at 1, 3, 6, 12, 24 and 48 postscald hours( PSH) and divided into two parts: one for histologic examination, and the other for the detection of CSL changes in the colonic smooth muscle tissue by flowcytometry method.</p><p><b>RESULTS</b>The electron microscope examination showed that the arrangement of cytoskeleton of SMC of the scalded rats during 1 to 3 PSH was disordered, and sparse, and the condensed area was uneven, with fragmentation. But the morphology and distribution of CSL gradually restored to normal state during 6 to 12 PSH, and it approached that of normal group at 48 PSH. The CSL content in the colonic smooth muscle tissue of scalded rats was obviously increased at 1 PSH (610+/-23) , decreased thereafter, evidently lower than that in control group at 3 PSH (92+/-17) , and then it started to increase at 12 PSH, exceeding the normal value at 24 PSH, and continued to rise until 48 PSH. There was significant difference in CSL content in the colonic smooth muscle tissue of the rats between scald and control group ( P < 0.05 or 0. 01).</p><p><b>CONCLUSION</b>Changes in the morphology and CSL content in the colonic smooth muscle tissue can be observed at early stage after a scald, which imply the kinetic balance between damage and repair in the body. In addition, changes in CSL content in the colonic smooth muscle tissue may be important factors in producing colonic dysfunction, damage of intestinal wall structure, and dynamic abnormalities of the colonic smooth muscle.</p>

Influence of scald and lipopolysaccharide on gastrointestinal motility / 中华烧伤杂志

<p><b>OBJECTIVE</b>To investigate the pathogenesis of gastrointestinal motility dysfunction as a result of scald and lipopolysaccharide (LPS) challenge in guinea pigs.</p><p><b>METHODS</b>Thirty guinea pigs were enrolled in the study and were randomly divided into 3 groups:i. e. control (n = 10, with intraperitoneal injection of isotonic saline), scald (n = 10, with 30% TBSA deep partial thickness burn) and LPS (n = 10, with intraperitoneal injection of LPS) groups. Thirty minutes after treatment, all animals were gavaged with carbolic ink. The propelled distance of the ink within the gastrointestinal tract was measured. The intestinal tissue was harvested and homogenized, and the contents of CGRP, Na+-K+-ATP enzyme, Mg2+-ATP enzyme, Ca2+-ATP enzyme, Ca2+-Mg2+-ATP enzyme were determined, and the delta phim of haustra coli smooth muscular cell mitochondria was assessed.</p><p><b>RESULTS</b>The propelled distance of the ink in the gastrointestinal tract in scald (53 +/- 9 cm) and LPS (91 +/- 10 cm) groups was obviously shorter than that in control group (142 +/- 11 cm, P < 0.01). Furthermore, the distance in scald group was shorter than that in LPS group (P < 0.01). The CGRP content in scald and LPS groups [52.0 +/- 39.0 microg/L and 20.0 +/- 23.0 microg/L] was obviously higher than that in control group (0.8 +/-2.0 microg/L, P <0.05 or 0.01), especially in scald group ( P < 0.05). The Na+-K+-ATP enzyme, Mg2+-ATP enzyme, Ca2+-ATP enzyme, Ca2+-Mg2+-ATP enzyme and the delta phim in scald and LPS groups were remarkably lower than those in control group (P <0.005), but there was no difference between scald and LPS groups (P > 0.05).</p><p><b>CONCLUSION</b>The gastrointestinal motility of guinea pigs could obviously be inhibited by scald and LPS, especially by scald. LPS might be the key factor to produce change in the membrane potential of mitochondria of intestinal smooth muscle after severe scald.</p>