Effects of high frequency oscillatory ventilation combined with incremental positive end-expiratory pressure on respiratory and circulatory functions of dogs with inhalation injury / 中华烧伤杂志

<p><b>OBJECTIVE</b>To study the effects of high frequency oscillatory ventilation (HFOV) combined with incremental positive end-expiratory pressure (IP) on respiratory and circulatory functions, and lung histopathology of dogs with smoke inhalation injury.</p><p><b>METHODS</b>After being treated with conventional mechanical ventilation, 12 dogs were inflicted with severe smoke inhalation injury and divided into group HFOV and group HFOV+IP according to the random number table, with 6 dogs in each group. Then they received corresponding ventilation for 8 hours respectively. Blood gas analysis results (pH value, PaO2 and PaCO2 levels) and hemodynamic parameters [heart rate, mean arterial pressure (MAP), pulmonary arterial pressure (PAP), central venous pressure (CVP), cardiac output (CO)] were recorded before injury, immediately after injury, and at post ventilation hour (PVH) 2, 4, 6, and 8. The dogs of two groups were sacrificed at PVH 8. A healthy dog without any treatment and a dog with smoke inhalation injury but no subsequent treatment were sacrificed in addition. Lung tissues of all dogs were obtained for histopathological observation. Lung injury score examination was conducted in both groups. Data were processed with rank sum test, analysis of variance of repeated measurement, and LSD- t test.</p><p><b>RESULTS</b>(1) The PaO2 levels in both groups were significantly decreased immediately after injury, compared with those before injury (with t values respectively 4.960, 5.310, P values all below 0.01). The PaO2 levels in both groups from PVH 2 to PVH 8 were significantly increased, compared with those observed immediately after injury (with t values from 4.930 to 6.050, P values all below 0.01). At PVH 2, 4, and 8, PaO2 levels in group HFOV+IP were significantly higher than those in group HFOV (with t values from 3.775 to 5.774, P values all below 0.01); no statistically significant differences were observed in pH value and PaCO2 level at each time point between two groups (with t values from 0.002 to 0.997, P values all above 0.05). (2) There were no statistically significant differences in MAP, PAP, and CVP within two groups at each time point (with F values from 1.316 to 4.959, P values all above 0.05). In group HFOV, heart rate from PVH 2 to PVH 8 was significantly lower than that observed immediately after injury (with t values from 3.780 to 8.970, P values all below 0.01). In group HFOV+IP, CO at PVH 4, 6, and 8 was significantly lower than that observed immediately after injury (with t values from 3.990 to 11.200, P values all below 0.01). There were no statistically significant differences in MAP, PAP, and CVP between two groups at the same time point (with t values from 0.089 to 2.123, P values all above 0.05). At PVH 4, 6, and 8, heart rate in group HFOV+IP was higher than that in group HFOV (with t values from 2.931 to 7.229, P < 0.05 or P < 0.01), while CO was lower (with t values from 4.297 to 11.206, P values all below 0.01). (3) Compared with those of the healthy dog, inflammatory cell infiltration and bleeding in the lung were observed in alveolar space in both group HFOV and group HFOV+IP, while the degree was less serious than that of the dog with smoke inhalation injury only. Compared with those of group HFOV, inflammatory cell infiltration in group HFOV+IP was less significant, the alveolar structure was relatively intact, and no thickening of alveolar walls was observed. The lung injury score in group HFOV [(3.27 ± 0.24) points] was higher than that of group HFOV+IP [(2.79 ± 0.31) points, t = 27, P < 0.05].</p><p><b>CONCLUSIONS</b>HFOV combined with IP can improve gas exchange and alleviate pulmonary injury without any adverse effect on blood gas analysis or hemodynamic parameters. Therefore, it may be considered as an appropriate mode of ventilation for the treatment of smoke inhalation injury.</p>

Observation on marrow-derived mesenchymal stem cells differentiating into functional cells in rabbit with smoke inhalation injury / 中华烧伤杂志

<p><b>OBJECTIVE</b>To observe the homing and differentiation of marrow-derived mesenchymal stem cells (MSC) transplanted intravenously in smoke inhalation injured rabbits.</p><p><b>METHODS</b>Thirty-two New Zealand big ear rabbits were divided into normal control group (NC), inhalation injury group (II), normal control + MSC treatment group (NM), and MSC treatment group (MT) according to the random number table, with 8 rabbits in each group. Rabbits in NC group were injected with 10 mL phosphate buffered saline (PBS) via ear marginal vein. Rabbits in NM group were injected with 10 mL PBS containing the third generation MSC labeled by BrdU (1 × 10(7) per 10 mL PBS) via ear marginal vein. Severe smoke inhalation injury model was reproduced in the other two groups, among them rabbits in II group were treated as rabbits in NC group, rabbits in MT group treated as rabbits in NM group. On the 7th and 28th day post treatment (PTD), lung tissue and trachea tissue were harvested from four groups for observation on injury with HE staining. Homing of MSC in injured tissue was observed with immunohistochemistry staining. The differentiation of MSC into functional cells was observed with immunohistochemical double staining of combining nuclear marker BrdU with lung (trachea) membrane-specific marker aquaporin-5 (AQP-5), alkaline phosphatase (AKP), CD34, and cytokeratin respectively.</p><p><b>RESULTS</b>(1) MSC homing in lung and trachea tissue was observed in MT group on PTD 7, which was not observed in NM group. (2) AQP-5, AKP, and CD34 positive MSC were observed in lung tissue in MT group on PTD 28, while cytokeratin positive MSC was not observed in trachea tissue. No positively marked MSC was observed in NM group. (3) Injury in lung and trachea was less severe in MT group than in II group; and the proliferation of fibroblasts was less in MT group.</p><p><b>CONCLUSIONS</b>Intravenous injection of MSC to rabbits with smoke inhalation injury can migrate to lung and trachea tissue at obviously inflammatory site, and differentiate into alveolar epithelial cells typeI and II, and pulmonary vascular endothelial cells, which may participate in the process of tissue repair in smoke inhalation injury.</p>

Effects of bone marrow-derived mesenchymal stem cells engraftment on vascular endothelial cell growth factor in lung tissue and plasma at early stage of smoke inhalation injury / 世界急诊医学杂志（英文）

BACKGROUND: This study was undertaken to determine the effect of mesenchymal stem cells (MSCs) engraftment on vascular endothelial cell growth factor (VEGF) in lung tissue, plasma and extravascular lung water at early stage of smoke inhalation injury. METHODS: A rabbit smoke inhalation injury model was established using a home-made smoke inhalation injury generator, and rabbits were divided into two groups randomly: a control group (S group, n=32) and a MSCs treatment group (M group,n=32). 10 ml PBS was injected via the ear marginal vein immediately at injury into the S group. Third generation MSCs with a concentration of 1×107/10 ml PBS were injected via the ear marginal vein immediately at injury into the M group. VEGF in peripheral blood and lung tissue were measured at 0 (baseline), 2, 4 and 6 hours after injection respectively and analyzed. The right lungs of rabbits were taken to measure lung water mass fraction. RESULTS: In the lung tissue, VEGF decreased gradually in the S group (P<0.05) and signifi cantly decreased in the M group (P<0.05), but it increased more signifi cantly than the values at the corresponding time points (P<0.05). In peripheral blood, VEGF increased gradually in the S group (P<0.05) and markedly increased in the M group (P<0.05), but it decreased more signifi cantly than the values at corresponding time points (P<0.05). CONCLUSION: MSCs engraftment to smoke inhalation injury could increase VEGF in lung tissue, decrease VEGF in plasma and reduce extravascular lung water, indicating its protective effect on smoke inhalation injury.

Effect of bone marrow-derived mesenchymal stem cells transplantation on the inflammatory response and lung injury in rabbit with inhalation injury / 中华烧伤杂志

<p><b>OBJECTIVE</b>To study the effect of bone marrow-derived mesenchymal stem cells (MSC) transplantation on the major inflammatory cytokines content in peripheral blood, lung water mass fraction, and lung tissue injury in rabbits with smoke inhalation injury.</p><p><b>METHODS</b>Sixteen adult New Zealand big ear rabbits were subjected to smoke inhalation injury and then were divided into pure injury group (PI, n = 8) and MSC transplantation group (MT, n = 8) according to the random number table. Via ear marginal vein, rabbits in PI group were injected with 10 mL phosphate buffered saline (PBS); rabbits in MT group were injected with 10 mL PBS containing the third passage MSC (1 x 10⁷ cell) isolated from marrow of healthy young New Zealand big ear rabbit. Another 8 rabbits were enrolled as normal control group (NC). Rabbits in NC group were injected with 10 mL PBS via ear marginal vein without smoke inhalation injury. Blood was harvested from rabbits in PI and MT groups at post injury hour (PIH) 2, 4, 6. Contents of TNF-α, IL-1β, IL-6, and IL-10 in serum were determined with ELISA. At PIH 24, left lung was harvested for morphology and histopathology observation; the right lung tissue was obtained to measure and calculate lung water mass fraction. Blood and lung tissue of rabbits in NC group were harvested and determined in the same way. Data were processed with t test.</p><p><b>RESULTS</b>(1) Serum contents of TNF-α in PI and MT groups at each time point were obviously higher than that in NC group (t = 2.43 - 9.57, P < 0.05 or P < 0.01). Serum contents of IL-1β and IL-6 in PI group at each time point were obviously higher than those in NC group (t = 8.49 - 19.80, P values all below 0.01). Serum content of IL-1β in MT group at each time point was close to that in NC group (t = 0.11 - 0.92, P values all above 0.05). Serum content of IL-6 in MT group at PIH 2 was close to that in NC group (t = 2.12, P > 0.05), but that of MT group increased significantly at PIH 4 and 6 (t = 2.83, P values all below 0.05). Serum contents of TNF-α, IL-1β, and IL-6 in MT group at each time point were obviously lower than those in PI group (t = 2.35 - 12.45, P < 0.05 or P < 0.01). (2) Serum content of IL-10 in MT group at PIH 2, 4, and 6 was respectively (13.0 ± 3.6), (11.6 ± 8.5), (15.2 ± 4.4) pg/mL, and they were higher than those in PI group [(5.5 ± 3.4), (5.0 ± 1.7), (7.9 ± 3.5) pg/mL, with t value respectively 4.28, 2.15, 3.67, P values all below 0.01]. Serum contents of IL-10 in PI and MT groups were obviously higher than that in NC group (t = 2.46-8.14, P < 0.05 or P < 0.01). (3) Lung tissue injury in MT group was alleviated markedly as compared with that in PI group. (4) At PIH 24, lung water mass fraction in MT group was (69 ± 7)%, which was obviously lower than that in PI group [(87 ± 6)%, t = 5.49, P < 0.01]. Compared with that in NC group [(48 ± 3)%], lung water mass fraction in PI and MT groups were increased obviously (with t value respectively 16.93 and 7.22, P values all below 0.01).</p><p><b>CONCLUSIONS</b>MSC transplantation can decrease pro-inflammatory cytokines, increase anti-inflammatory cytokines, decrease lung water mass fraction, ameliorate systemic inflammatory response, and protect lung tissue in rabbits with smoke inhalation injury.</p>

Changes in the calcitonin content after inhalation injury in dogs / 中华烧伤杂志

<p><b>OBJECTIVE</b>To investigate the changes in the serum content of immunoreactive calcitonin (iCT) after burns or inhalation injury, and to explore its diagnostic significance.</p><p><b>METHODS</b>Twenty-four dogs were randomized into 4 groups, i. e. A (n = 6, with moderate degree inhalation injury) , B ( n = 6, with severe inhalation injury), C (n = 6, with most severe inhalation injury) and D (n = 6, with severe burns) groups. The serum content of iCT and blood gas analysis before and after injury were determined at different time points. The degree of inhalation injury was determined with fibrobronchoscopic examination at 6 post-inhalation injury hour (PIH).</p><p><b>RESULTS</b>(1) Fiber bronchoscopic examination showed that the degree of inhalation injury in each group was coincident with the anticipation. (2) The serum content of iCT in each group at 1 PIH was obviously higher than that before injury, and it was evidently higher in A, B and C groups than that in D group at 4 PIH. The peak value of iCT in group A at 24 PIH was (453+/-224) ng/L, and it increased gradually in B and C groups at 48 PIH. The serum content of iCT increased continually from 2 PIH on, and it reached (125+/-41) ng/L at 48 PIH. (3) Compared with PaO2 value before injury (109+/-8) mmHg, there was no obvious difference of the PaO, in A and D groups. PaO2 value in B and C group began to descend continually at 8 PIH (65+/-6) mmHg, and that in C group began to descend at 4 PIH (71+/-9) mmHg. PaCO2 value in C group began to increase at 24 PIH(52+/-11) mmHg when compared with that before injury(38+/-5 ) mmHg.</p><p><b>CONCLUSION</b>The changes in the serum level of iCT within 8 PIH occurred much earlier than PaO2 and PaCO2, thus it has the same diagnostic significance as fibers bronchoscopic examination.</p>