长波紫外线对大鼠皮肤脂质过氧化和胶原的影响及防晒剂的防护

目的 ]　探讨长波紫外线 (UVA )对大鼠皮肤脂质过氧化和胶原合成的影响及防晒化妆品的防护效果。　方法 ]　UVA照射组和涂抹防晒化妆品组大鼠经UVA照射 8周后 (总计量为 30 6 1.8J/cm2 ) ,测定皮肤丙二醛 (MDA)、超氧化物歧化酶 (SOD)、总胶原和可溶性胶原的含量。　 结果 ]　UVA照射组大鼠皮肤MDA(11.36± 1.92nmol/mL)高于对照组 (7.0 3± 1.11nmol/mL) (P <0 .0 1) ,高于防晒化妆品组 (8.0 5± 1.2 8nmol/mL) (P <0 .0 1)。UVA照射组总胶原(2 5 .98± 3.0 6mg/g)低于对照组 (31.36± 3.99mg/ g) (P <0 .0 5 ) ,与防晒化妆品组 (2 8.71± 3.72mg/ g)差异无显著性 (P>0 .0 5 )。UVA照射组可溶性胶原 (4.2 5± 0 .83mg/ g)低于对照组 (6 .33± 1.19mg/g) (P <0 .0 1) ,低于防晒化妆品组(5 .70± 1.14mg/g) (P <0 .0 5 )。对照组、UVA照射组和防晒化妆品组的SOD分别为 18.6 9± 2 .82 U/mL、16 .40± 2 .14U /mL、17.86± 2 .95U/mL ,三者差异没有显著性 (P >0 .0 5 )。　 结论 ]　UVA能使皮肤脂质发生过氧化和降低皮肤可溶性胶原的含量 ,防晒化妆品有一定的防护效果。

Study on the effects of long- wave ultraviolet on lipid peroxidation and collagen of rats' skin and sunscreen's protection

Objective] To explore the effects of long-wave ultraviolet (UVA) on lipid peroxidation and collagen synthesis of rats' skin and sunscreen's protection. Methods] Rats were divided into control group, UVA irradiated group and sunscreen group. The levels of malondialdehyde (MDA), superoxide dismutase (SOD), total collagen and dissoluble collagen of rats skin irradiated with UVA for eight weeks(total dosage 3061.8J/cm 2)were determined. Results] Significantly higher level of MDA in UVA irradiated group(11.36±1.92 nmol/mL) was observed as compared with those of the control group (7.03± 1.11 nmol/mL, P<0.01) and those of sunscreen group(8.05±1.28 nmol/mL, P<0.01). The total collagen of UVA irradiated group(25.98±3.06 mg/g) was significantly lower as compared with those of the control group(31.36±3.99 mg/g, P<0.05) but the difference between the total collagen of UVA irradiated group and sunscreen group(28.71±3.72 mg/g, P> 0.05) was not significant. The dissoluble collagen of UVA irradiated group(4.25±0.83 mg/g) was lower than those of the control group(6.33±1.19 mg/g, P<0.01) and the sunscreen group(5.70±1.14 mg/g, P<0.05). The levels of SOD of UVA irridiated group, the control group and sunscreen group were 18.69±2.82 U/mL,16.40±2.14 U/mL and 17.86±2.95 U/mL respectively, difference were non-significant among them. Conclusion] UVA irradiation could induce lipid peroxidation and lower the level of collagen of rat skin. The sunscreen possesses some protective effects on rat skin.