Studies On The Apoptosis Of Skin Caused By Trichloroethylene In The BALB/c Hairless Mice

ObjectTo explore the mechanism of skin cellular apoptosis caused by trichloroethylene, this research detected the damage to the skin of BALB/c hairless mice caused by trichloroethylene, determine cell apoptosis level and signal transduction pass-way and vitamin E or GbE's protective effect on it.MethodsMature female BALB/c hairless mice were purchased from Shanghai slac experimental animal co, LTD. The animals were divided into Blank control group, vehiculum (olive oil) control group, 10%TCE, 20%TCE, 40%TCE, 80%TCE, 100%TCE in random. 100ul different concentrations of TCE were overlaid in 2.5cm×2.5cm size area on the dorsal skin of BALB/c hairless mice. Vitamin E with the concentrations of 5%, 10% or 20% or GbE with the concentrations of 0.1%, 1% or 10% were used to protect the damage caused by 100%TCE. Then fast overlaid plastic film by non-irritant strapping on the dorsal skin for 4h, then use Sodium Chloride to remove the residual TCE after every test.After 24h the dorsal skin including dermis and epidermis was quickly removed, fixed, dehydrated, embedded and cut into slices. JEM-1230 electronic microscope was used to determine the morphologic change of the cells, TUNEL was used to determine the cellular apoptosis level of the keratinocytes, immunohistochemistry method was used to determine caspase-3, caspase-8, caspase-9, cytc and AIF expression. Protective effects of vitamin E or GBE were also determined in this research. Results:1. Through the observation by the transmission electron microscope, the mitochondrions of keratinocyte appear swelling and vacuoles in the cellular plasma, nuclear condensation was also displayed. Cellular apoptosis detected by TUNEL showed that both apoptosis index and caspase-3 level displayed concentration dependent significance while 40%, 80% or 100% TCE was used.2. Immunohistochemistry was used to determine caspase-9 and cytc level in keratinocyte cells. Significance was shown while TCE concentrations higher than 10% were used.3. Detection of caspase-8 by immunohistochemistry showed no significance among different concentrations, caspase-8 expression at low level.4. Detection of AIF level by immunohistochemistry showed significance while TCE concentrations higher than 10% were used, compared with vehiculum control. Highest level of AIF was displayed when 40% TCE was used.5. Different concentrations of Vit E or GbE were administered to the skin treated with 100% TCE, apoptosis index, AIF and caspase-9 level were down regulated, concentration dependently. The groups treated with the highest concentration of Vit E or GbE can protect the skin damage as well as vehiculum control.Conclusion:1. Certain concentration of TCE can cause cellular apoptosis in hairless mice.2. Cellular apoptosis caused by TCE was shown, and mitochondrial pass-way plays critical role in it.3. Vit E or GbE may protect the cells from TCE induced apoptosis and alleviate the damage caused by TCE.