| BackgroundTrichloroethylene (TCE) is a kind of organic solvent that has been widely used inindustry, in addition to as raw materials for a high-molecular compound,60%hasbeen used as a cleaning agent for metal parts and electronic components by hardware,toys, electronics and other industries,mainly used in cleaning circuit boards, the metalsurface soil decontamination, also used as extraction agent of oils and paraffin wax,can be used for dyeing and printing ink, spots detergents, typing correction fluid etc..A large number of clinical cases DMLT patients in addition to systemic skin damage,accompanied by liver damage, and the DMLT’s death is mainly due to liver failure,and therefore liver damage mechanism research in DMLT prevention and controlwork is particularly important. But related research also found, medicamentosa-likedermatitis induced by TCE, especially the immune liver injury, cannot be completelyexplained with delayed allergy type IV, suggesting the liver function in patients withDMLT appear during injury in type IV allergy, there may also be involved in themechanism of complement activation.ObjectiveBy detecting the serum and liver of different groups and time-point by TCEsensitized mice in complement activation products of C3a, C5a and C5b-9expressionlevels, combined with liver function examination, liver viscera coefficient ofexamination, to investigate the relationship of TCE sensitized mice complementactivation and liver injury, finally expounds the harm and mechanism of TCE andprovide theoretical basis for prevention and control countermeasures. MethodsSelect75of the6~8weeks healthy female BALB/c mice, which were randomlydivided into blank control group, solvent control group and TCE treatment group. Theestablishment of BALB/c mice sensitized model, to observe and record thehypersensitive reaction of the skin of the back of mice tested parts.According to theresults of sensitivity of24h after the last excited in mice and different sampling point(respectively after the last excited24h,48h,72h and7d blood collection, sterile skintissue and liver tissue),TCE treatment group was divided into sensitized24h,48h,72h and7d group and not sensitized24h,48h,72h and7d groups. Detect the level ofthe serum C3a-desArg, C5a-desArg and C5b-9by ELISA. Expression of C3a, C5aand C5b-9in liver tissues was detected by immunohistochemistry. Detect C5b-9expression of liver tissues by direct immunofluorescence. Detect the expression of C3mRNA level in liver tissue by RT-PCR.Results1. Sensitization rateIn the skin sensitization test, the blank control group and solvent control groupshowed no erythema or edema, TCE treatment group of63mice in23dorsal skinappear different degree of erythema and edema, the remaining40were not sensitizedgroup, sensitization rate to36.5%and induced mice were sensitized to moderateintensity.2．The detection results of liver function and relative organ weightEach index of blank control group comparing and solvent control group of liverfunction, shows no significant difference (P>0.05).24h,48h,72h,7d sensitized groupcompared to the control and solvent group, AST increased obviously, the differencewas statistically significant (P<0.05), compared with the corresponding unsensitizedgroup, AST of24h,48h,72h,7d sensitized group increased obviously, the differencewas statistically significant (P<0.05). ALT examination found that, compared to theblank control group, solvent control group shows no significant difference (P>0.05),ALT in72h sensitized group was significantly higher than solvent control group, the difference was statistically significant (P<0.05), compared with the correspondingunsensitized group, the difference was statistically significant (P<0.05). Comparedwith7d sensitized group and solvent control group shows no significant difference(P>0.05).Compared with the blank control group and solvent control group, relative organweight of mice did not change significantly, the difference was not statisticallysignificant (P>0.05), however,24h,48h,72h,7d sensitized group relative organweight was significantly higher than that of solvent control group, the difference wasstatistically significant (P<0.05), at the same time point comparisons between groups,the relative organ weight of sensitized group were higher than the correspondingunsensitized group, the difference was statistically significant (P<0.05), and72hreached the highest in after the last challenge, no significant differences in24h,48h,72h sensitized group (P>0.05).3. C3a-desArg, C5a-desArg and C5b-9level in serum3.1The level of C3a-desArg in serum: After the last challenge, compared with thesolvent control group, the level of serum C3a-desArg of mice in blank control groupshows no significant difference (P>0.05).24h,48h,72h,7d sensitized group wassignificantly higher than that of the solvent control group, the difference wasstatistically significant (P<0.05), at the same time point in comparison, sensitizedgroup C3a-desArg was higher than that in the corresponding unsensitized group, thedifference was statistically significant (P<0.05),7d sensitized group and solventcontrol group had no significant difference (P>0.05). Among in24h,48h,72hsensitized group, there were no significant differences (P>0.05).3.2The level of C5a-desArg in serum: After the last challenge, compared with thesolvent control group, the level of serum C5a-desArg of mice in blank control groupshows no significant difference (P>0.05).24h,48h,72h,7d sensitized group wassignificantly higher than that of the solvent control group, the difference wasstatistically significant (P<0.05); at the same time point in comparison, sensitizedgroup C5a-desArg levels were higher than those of unsensitized group, the difference was statistically significant (P<0.05), there was no significant difference among24h,48h,72h,7d sensitization groups (P>0.05).3.3The level of C5b-9in serum: After the last challenge, compared with the solventcontrol group, the level of serum C5b-9of mice in blank control group shows nosignificant difference (P>0.05).24h,48h,72h,7d sensitized group were significantlyhigher than the control group, the difference was statistically significant (P<0.05),compared with the solvent control group,72h sensitized group significantly increased,at the same time point of comparison, the difference was statistically significant(P<0.05),72h sensitized group C5b-9higher than unsensitized group, the differencewas statistically significant (P<0.05), there was no significant difference in24h,48h,72h, and7d sensitized group (P>0.05).4. Expression of C3a, C5a and C5b-9in liver tissues after provocation4.1The expression of C3a level: Compared to the blank control group and solventcontrol group, there was no significant difference (P>0.05). Sensitized24h,48h,72hgroup compared with the solvent control group the score increased significantly, thedifference was statistically significant (P<0.05), expression of sensitized72h groupwas the highest, there was no significant difference between the sensitivity of24h,48h,72h group (P>0.05), however, expression of C3a level in7d sensitized group wassignificantly lower, and compared to solvent group showed no significant difference(P>0.05).4.2The expression of C5a level: Compared with the blank control group and solventcontrol group, there was no significant difference (P>0.05). Sensitized24h,48h,72h,7d group compared with the solvent control group, the difference was statisticallysignificant (P<0.05), expression of sensitized72h group was the highest, there was nosignificant difference between the sensitivity of24h,48h,72h group (P>0.05).However, sensitized7d expression level of C5a was significantly lower, compared tothe sensitization72h group, the differences were statistically significant (P<0.05).4.3The expression of C5b-9level: Compared with the blank control group andsolvent control group, there was no significant difference (P>0.05).24h,48h,72h,7d sensitized group compared with the solvent control group significantly increased, thedifference was statistically significant (P<0.05), expression of sensitized72h groupwas the highest, there was no significant difference between24h,48h,72h sensitizedgroup (P>0.05). At the same time point between the phase comparison, sensitized24h,48h,72h group C5b-9expression levels were higher than non-sensitized24h,48h,72h group, the difference was statistically significant (P<0.05).7d sensitized andnon-sensitized group were no significant change (P>0.05).5. Immunofluorescence assay excited C5b-9expression in the liver tissueWe carried out immunofluorescence to further detect the expression of C5b-9in theliver,24h,48h,72h,7d sensitized group can see a clear expression, and in the72hsensitized group was the highest.6. Detect the expression of C3mRNA by RT-PCRUse RT-PCR technique to detect C3mRNA expression of the mouse liver tissue,grey value analysis showed that24h,48h sensitization group of C3mRNA expressionwas obviously higher than blank control group, solvent control group and eachnon-sensitized (P<0.05), but the C3mRNA of72h sensitization group wassignificantly reduced, the difference was statistically significant (P<0.05), theexpression of7d sensitization group was no statistical difference (P>0.05).Conclusions1. TCE could sensitize mice in certain dose, sensitization rate was36.5%, and TCEhas moderate sensitization effect on the skin of BALB/c mice.2. TCE exposure may cause liver damage in mice and viscera coefficient change, thedegree of injury was aggravated with time.3. Complement in TCE sensitization may be activated and may play an importantimmunomodulatory role of complement activation and its product in the process ofTCE contact sensitization dermatitis. |
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