42℃热处理在UVB诱导黑素细胞氧化损伤中的作用

Effect of heat treatment at 42℃ on ultraviolet B-induced oxidative injury to human melanocytes

目的探讨热处理在UVB诱导的人黑素细胞氧化应激损伤中的作用。方法体外培养原代人表皮黑素细胞，将纯化的MC分为4个处理组：对照组（37cc正常培养）、热处理组（42oC孵育1h）、UVB处理组（100mJ／c㎡ UVB照射）、联合处理组（42℃孵育1h后给予100mJ／c㎡UVB照射），各组连续处理3d。MrIT法检测细胞活率，生物化学法检测超氧化物歧化酶活力和丙二醛浓度，流式细胞仪检测细胞内活性氧和细胞凋亡率。结果对照组细胞活率、细胞凋亡率、超氧化物歧化酶活力、丙二醛浓度、活性氧荧光强度分别为：（100±6．14）％、（4．66±0．58）％、（53．39±8．23）U／gprot、（1．09±0．32）mmol／gprot、1070．854±42．07。UVB照射可以明显提高MC凋亡率[（24．14±2．90）％]、丙二醛[（1．654±0．33）mmol／gprot]和细胞内活性氧（1416．45±79．12）水平，降低细胞活率[（50．23±5．36）％]和超氧化物歧化酶活力[（31．98±11．89）U／gprot]，而热处理可以显著降低UVB诱导的凋亡[（14．9±1．49）％]，降低丙二醛[（1．10±0．26）mmol／gprot]、活性氧（1033．30±68．41）的含量，同时恢复细胞的活率[（74．12±6．17）％）]和超氧化物歧化酶活力[（51．63±6．55）U／gprot]。结论热处理对UVB诱导的黑素细胞的氧化应激损伤具有保护作用。

Objective To evaluate the effect of heat treatment on uhraviolet B （UVB）-induced oxidative injury to human melanocytes. Methods Melanoeytes were isolated from adult foreskins, and subjected to a primary culture. After 3 - 4 passages of subculture, the melanocytes were classified into 4 groups： control group incubated at 37 ℃, heat treatment group incubated at 42 ℃ for 1 hour, UVB group exposed to UVB irradiation at 100 mJ/cm2, combination group receiving heat treatment at 42 ℃ for 1 hour followed by UVB irradiation at 100 mJ/cm2. After three successive days of treatment, MqT assay was performed to evaluate cell viability, a biochemical method to determine the activity of superoxide dismutase （SOD） and concentration of malonaldehyde （MDA）, and flow cytometry to detect intracellular reactive oxygen species （ROS） and apoptosis in melanocytes. Results The cell survival rate, apoptosis rate, SOD activity, MDA concentration and ROS level were （100 ± 6.14）%, （4.66 ± 0.58）%, （53.39 ± 8.23） U/gprot, （ 1.09 ±0.32） mmol/gprot, and 1070.85 ± 42.07 in the control group respectively. UVB exposure induced a significant increase in apoptosis rate （24.14% ± 2.90%, P 〈 0.001 ）, MDA concentration （1.65 ± 0.33 mmol/gprot, P 〈 0.01 ） and ROS level （ 1416.45 ± 79.12, P 〈 0.01 ）, but a significant decrease in cell survival rate （50.23% ± 5.36%, P 〈 0.01 ） and SOD activity （31.98 ± 11.89 U/gprot, P 〈 0.01 ） in the UVB group compared with the control group, while the heat pretreatment markedly downregulated the UVB-induced increase in apoptosis rate （ 14.9% ± 1.49%, P 〈 0.001 ）, MDA concentration （ 1.10 ± 0.26 mmol/gprot） and ROS level （ 1033.30 ± 68.41, P 〈 0.01 ）, as well as the decrease in cell survival rate （ 74.12% ± 6.17%, P 〈 0.01 ） and SOD activity （51.63 ± 6.55 U/gprot, P 〈 0.01 ） in the combination group. Conclusion Heat treatment could protect melanocytes from UVB-indueed oxidative injury.