Research progress on the role of oxidative stress in ischemia-reperfusion injury of marginal donor liver transplantation / 器官移植

Common marginal donor liver mainly consists of fatty donor liver, elderly donor liver, small volume donor liver and liver graft from donation after cardiac death (DCD), etc. The application of marginal donor liver may resolve the severe shortage of donor liver to certain extent. Nevertheless, marginal donor liver yields a higher risk of ischemia-reperfusion injury (IRI) and causes more severe IRI than normal donor liver, which is a main cause for the failure of transplantation. In addition, oxidative stress is a major risk factor causing IRI of marginal donor liver. Therefore, how to mitigate oxidative stress and alleviate IRI of marginal donor liver has become a hot spot in clinical practice. Reactive oxygen species (ROS)-mediated oxidative stress occurs throughout the whole process of IRI. In this article, the role of oxidative stress in IRI of marginal donor liver transplantation and the ROS-targeted prevention and treatment were reviewed, aiming to provide reference for clinical practice.

Effects of mouse adipose-derived stem cell conditioned medium on the apoptosis of keratinocytes induced by thermal injury in vitro / 中华烧伤杂志

<p><b>OBJECTIVE</b>To investigate the effects of mouse adipose-derived stem cell conditioned medium (ADSC-CM) on apoptosis of keratinocytes (human epithelial cell line HaCaT) induced by thermal injury in vitro.</p><p><b>METHODS</b>(1) Adipose-derived stem cells (ADSCs) from inguinal adipose tissue of 5 healthy BALB/c mice were isolated, cultured, and purified by collagenase digestion in vitro. The 3rd passage of cells were collected for morphologic observation, detection of expressions of surface markers CD31, CD34, CD45, CD90, and CD105 with flow cytometer, and identification of adipogenic and osteogenic differentiation. (2) HaCaT cells were incubated in water at 51.5 °C for 35 seconds to reproduce thermal injury model, and then the apoptosis rate was detected immediately after injury by flow cytometer. (3) Thermally injured HaCaT cells were divided into routine culture group (RC, cultured with DMEM containing 10% FBS), serum-free group (cultured with serum-free DMEM), 50%ADSC-CM group (cultured with DMEM containing 50%ADSC-CM), and 100%ADSC-CM group (cultured with 100%ADSC-CM) according to the random number table. After 24 hours, apoptosis of HaCaT cells was observed by acridine orange-ethidium bromide (AO-EB) staining; apoptotic rate was determined by flow cytometer; the mRNA and protein levels of Bcl-2 and caspase-3 were respectively determined by real-time fluorescent quantitative RT-PCR technique and Western blotting (protein level was denoted as gray value); the cell cycles were determined by flow cytometer. All above experiments were repeated for 3 times. Data were processed with one-way analysis of variance and LSD- t test.</p><p><b>RESULTS</b>(1) The 3rd passage of cells proliferated well showing fusiform shape similar to fibroblasts. The positive expression rates of CD31, CD34, and CD45 were less than 10.0%, while those of CD90 and CD105 were above 90.0%. The cells could differentiate into adipocytes and osteoblasts. They were identified as ADSCs. (2) Immediately after injury, apoptotic rate of HaCaT cell was (9.8 ± 0.4)%. (3) The number of apoptotic cells was significantly higher in serum-free group than in the other three groups with AO-EB staining. The apoptotic rate of serum-free group [(8.1 ± 1.2)%] was significantly higher than that of 50%ADSC-CM group [(6.0 ± 0.8)%], group RC [(4.6 ± 0.8)%], or 100%ADSC-CM group [(3.1 ± 0.4)%], with t values respectively 3.02, 4.96, 6.60, P values below 0.01. There was no statistically significant difference in apoptotic rate between group RC and 100% ADSC-CM group (t = 1.50, P > 0.05), while statistically significant difference was found between 100% ADSC-CM group and 50%ADSC-CM group (t = 10.21, P < 0.01). (4) The mRNA level of Bcl-2 of serum-free group (0.34 ± 0.08) was significantly lower than that of group RC, 50%ADSC-CM group, and 100%ADSC-CM group (0.98 ± 0.04, 0.77 ± 0.05, 1.06 ± 0.04, with t values respectively 12.87, 8.07, 14.11, P values below 0.01). Compared with that of 100%ADSC-CM group, the mRNA level of Bcl-2 of group RC was slightly decreased (t = 0.08, P > 0.05) and that of 50%ADSC-CM group was significantly decreased (t = 8.08, P < 0.01). (5) The mRNA level of caspase-3 of serum-free group (1.15 ± 0.05) was obviously higher than that of 50%ADSC-CM group (0.72 ± 0.11), group RC (0.41 ± 0.03), or 100%ADSC-CM group (0.38 ± 0.11), with t values respectively 6.93, 13.97, 22.79, P values below 0.01. Compared with 100%ADSC-CM group, the mRNA level of caspase-3 was slightly increased in group RC (t = 0.05, P > 0.05) and significantly increased in 50%ADSC-CM group (t = 4.77, P < 0.01). (6) The protein level of Bcl-2 was significantly lower in serum-free group (0.93 ± 0.04) than in group RC, 50%ADSC-CM group, and 100%ADSC-CM group (1.74 ± 0.06, 1.32 ± 0.05, 1.90 ± 0.04, with t values respectively 20.45, 11.15, 31.38, P values below 0.01). Compared with that of 100%ADSC-CM group, the protein level of Bcl-2 of group RC was slightly decreased (t = 1.33, P > 0.05), but that of 50%ADSC-CM group was obviously decreased (t = 17.30, P < 0.01). (7) The protein level of caspase-3 was obviously higher in serum-free group (0.63 ± 0.08) than in 50%ADSC-CM group, group RC, and 100%ADSC-CM group (0.46 ± 0.03, 0.29 ± 0.08, 0.21 ± 0.03, with t values respectively 3.28, 5.05, 8.46, P values below 0.01). Compared with that of 100%ADSC-CM group, the protein level of caspase-3 of group RC was slightly increased (t = 0.08, P > 0.05), but that of 50%ADSC-CM group was significantly increased (t = 3.52, P < 0.05). (8) Compared with that of serum-free group, the percentage of cells in G2/M phase of each of the other 3 groups was significantly decreased (with t values respectively 6.88, 4.08, 7.28, P < 0.05 or P < 0.01). Compared with that in serum-free group, the percentage of cells in S phase was significantly increased in group RC and 100% ADSC-CM group (with t values respectively 2.67 and 2.40, P values below 0.05). There was no statistically significant difference in the percentage of cells in G0/G1 phase among all groups (F = 0.70, P > 0.05).</p><p><b>CONCLUSIONS</b>100% xenogeneic ADSC-CM can suppress apoptosis of HaCaT cells induced by thermal injury through regulating the expression of Bcl-2 and caspase-3, and accelerate cell cycle progression by ameliorating the retardation of cell growth in G2/M phase, and all these effects may give rise to some potential in the treatment of burn wounds at early stage.</p>

Effects of activating silent information regulator 1 on early myocardial damage in severely burned rats / 中华烧伤杂志

<p><b>OBJECTIVE</b>To explore the effects of activating silent information regulator 1 (SIRT1) on early myocardial damage in severely burned rats.</p><p><b>METHODS</b>Twenty-four healthy male SD rats were divided into sham injury group (SI), scald group (S), and resveratrol (RSV) treatment group (RT) according to the random number table, with 8 rats in each group. Rats in groups S and RT were inflicted with 30% TBSA full-thickness scald on the back by immersing in 95 °C water for 18 s. Immediately after injury, rats in group S were intraperitoneally injected with 10 mL normal saline (50 mL/kg) and those in group RT with 10 mL normal saline (50 mL/kg)+10 µL RSV in the concentration of 1 g/mL (50 mg/kg). Backs of rats in group SI were immersed in 20 °C room temperature water for 18 s to simulate the scald process. Heart tissues and aorta abdominalis blood samples were collected at post injury hour (PIH) 6. The histomorphology of heart tissues was observed with HE staining. The serum contents of creatine kinase (CK) and lactate dehydrogenase (LDH) were determined with ELISA. The protein expressions of SIRT1 and caspase-3 and mRNA expressions of SIRT1, caspase-3, IL-1β, and TNF-α in heart tissue specimens were determined with Western blotting and real-time fluorescent quantitative RT-PCR (with protein level denoted as gray value). Data were processed with one-way analysis of variance and LSD- t test.</p><p><b>RESULTS</b>(1) In group SI, myocardial fibers were in irregularly cylindrical shape, neatly arranged, and the transverse striation were distinct. In group S, myocardial interstitial edema, disorder of myocardial fiber arrangement, and cytoplasm destruction were observed. In group RT, the degrees of myocardial interstitial edema, disorder of myocardial fiber arrangement, and cytoplasm destruction were alleviated in comparison with those of group S. (2) The serum contents of CK and LDH of rats in group S were respectively (2 385 ± 712) and (2 551 ± 196) U/L, which were significantly higher than those in the group SI [(290 ± 59) and (759 ± 60) U/L, with t values respectively 9.466 and 25.452, P values below 0.01]. The serum contents of CK and LDH of rats in group RT were respectively (1 336 ± 149) and (2 209 ± 133) U/L, which were significantly lower than those of group S (with t values respectively -4.506 and -4.860, P values below 0.01). (3) The protein expressions of SIRT1 and caspase-3 in heart tissue of rats in group S were respectively 0.47 ± 0.11 and 0.48 ± 0.12, which were significantly higher than those in group SI [0.18 ± 0.06 and 0.09 ± 0.05, with t values respectively 4.813 and 9.014, P values below 0.01]. The protein expression of SIRT1 in heart tissue of rats in group RT was 0.74 ± 0.18, which was significantly higher than that of group S (t = 4.561, P < 0.01); the protein expression of caspase-3 in heart tissue of rats in group RT was 0.21 ± 0.08, which was significantly lower than that of group S (t = -6.239, P < 0.01). (4) The mRNA expressions of SIRT1, caspase-3, IL-1β, and TNF-α in heart tissue of rats in group S were respectively 2.33 ± 0.24, 1.96 ± 0.20, 2.46 ± 0.21, 1.89 ± 0.37, which were significantly higher than those in group SI (1.00 ± 0.07, 1.00 ± 0.06, 1.00 ± 0.08, 1.00 ± 0.09, with t values respectively 14.961, 12.823, 18.559, 6.679, P values below 0.01). The mRNA expression of SIRT1 in heart tissue of rats in group RT was 2.89 ± 0.31, which was significantly higher than that of group S (t = 3.997, P < 0.01). The mRNA expressions of caspase-3, IL-1β, and TNF-α in heart tissue of rats in group RT were respectively 1.31 ± 0.08, 1.64 ± 0.09, 1.25 ± 0.08, which were significantly lower than those of group S (with t values respectively -8.264, -10.245, -4.818, P values below 0.01).</p><p><b>CONCLUSIONS</b>The expression of SIRT1 in heart tissue is upregulated in the early stage of severely burned rats. Activation of SIRT1 by RSV can alleviate myocardial tissue injury and reduce apoptosis of cardiac myocytes and secretion of IL-1β and TNF-α.</p>