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[Effects of hydrogen sulfide on the secretion of cytokines in macrophages of deep partial-thickness burn wound in rats].

OBJECTIVE
To analyze the effects of exogenous hydrogen sulfide on the secretion of growth factors basic fibroblast growth factor (bFGF) and transforming growth factor β1 (TGF-β1), as well as inflammatory mediators tumor necrosis factor α (TNF-α) and interleukin 1β (IL-1β) in macrophages of deep partial-thickness burn wound in rats.


METHODS
Seventy-eight SD rats were divided into normal control group (n=6), pure burn group, sodium hydrosulfide group, propargylglycine (PPG) group, and sodium hydrosulfide+ PPG group according to the random number table, with 18 rats in each of the latter four groups. Rats in normal control group did not receive any treatment, while rats in the other four groups were inflicted with 5% total burn surface area deep partial-thickness scald (hereinafter referred to as burn) on the back. Immediately after burn, rats in pure burn group, sodium hydrosulfide group, and group PPG were intraperitoneally injected with saline 2 mL/kg, sodium hydrosulfide 56 μmol/kg, and PPG 45 mg/kg respectively, while those in sodium hydrosulfide+ PPG group were intraperitoneally injected with sodium hydrosulfide 56 μmol/kg and PPG 45 mg/kg, once a day till the day before harvesting specimen. Six rats of normal control group fed for one week, and 6 rats from each of the rest four groups on post injury day (PID) 3, 7, 14 were collected respectively. Normal skin on the back of rats in normal control group and tissue in the base of wound of rats in the other four groups were harvested to isolate macrophages, and then the content of bFGF, TGF-β1, TNF-α, and IL-1β in culture supernatant of macrophages was detected with enzyme-linked immunosorbent assay. Data were processed with one-way analysis of variance, analysis of variance of factorial design, and LSD test.


RESULTS
Compared with that of normal control group [(42.6±2.5) and (18±4) pg/mL], the content of bFGF and TGF-β1 in culture supernatant of macrophages of rats in pure burn group was obviously increased at each time point (with P values below 0.01), peaking on PID 14 at (141.6±7.7) and (580±16) pg/mL respectively. Compared with that of pure burn group, the content of bFGF and TGF-β1 in culture supernatant of macrophages of rats in sodium hydrosulfide group was obviously increased at each time point (with P values below 0.01), peaking on PID 14 at (193.7±10.9) and (793±12) pg/mL respectively, while the content of bFGF and TGF-β1 in culture supernatant of macrophages of rats in group PPG was obviously decreased at each time point (with P values below 0.01), reaching the nadir on PID 3 at (62.0±7.1) and (170±10) pg/mL respectively. The content of bFGF and TGF-β1 in culture supernatant of macrophages of rats in sodium hydrosulfide+ PPG group was obviously lower than that of sodium hydrosulfide group but obviously higher than that of group PPG at each time point (with P values below 0.01), peaking on PID 14 at (151.3±9.0) and (579±9) pg/mL respectively. Compared with that of normal control group [(97±6) and (31±6) pg/mL], the content of TNF-α and IL-1β in culture supernatant of macrophages of rats in pure burn group was obviously increased at each time point (with P values below 0.01), peaking on PID 3 at (924±8) and (290±10) pg/mL respectively. Compared with that of pure burn group, the content of TNF-α and IL-1β in culture supernatant of macrophages of rats in sodium hydrosulfide group was obviously decreased at each time point (with P values below 0.01), reaching the nadir on PID 14 at (346±10) and (120±5) pg/mL respectively, while the content of TNF-α and IL-1β in culture supernatant of macrophages of rats in group PPG was obviously increased at each time point (with P values below 0.01), peaking on PID 3 at (1 232±13) and (410±10) pg/mL respectively. The content of TNF-α and IL-1β in culture supernatant of macrophages of rats in sodium hydrosulfide+ PPG group was obviously higher than that of sodium hydrosulfide group but obviously lower than that of group PPG at each time point (with P values below 0.01), reaching the nadir on PID 14 at (488±16) and (144±6) pg/mL respectively.


CONCLUSIONS
Supplementation of exogenous hydrogen sulfide in small dosage can increase the secretion of growth factors bFGF and TGF-β1 in macrophages of wound in rats with deep partial-thickness burn in the early stage and reduce the release of inflammatory mediators TNF-α and IL-1β in the meantime, thus affecting the healing of wound.