Objective To observe the effect of astragaloside IV (A) and SB203580 antagonize cadmium (Cd) toxicity on expression of associated protein and blood-testis barrier(BTB) in rats and to study the protective mechanism of A on it.Methods Totally 21 SD male rats were randomly divided into 7 groups, 3 rats per group:Cd [ intraperitoneally injected with 0.1%CdCl2,1mg/(kg?d)],Cd+A [at the above dose of CdCl2,at the same time with A,10mg/(kg?d)], and Cd +SB203580 [at the above dose of CdCl2,at the same time with SB203580,100μg/(kg?d)], each of the above groups was further divided into continuous five and ten days treatment groups .The control group was intraperitoneally injected with equal dosage of normal saline .The testes were studied by light , electron microscopy , immunohistochemistry and Western blotting .Results In the control group ,irregular and lightly stained nuclei of Sertoli cell ( Sc) in seminiferous tubules were observed by HE staining .A continuous electron density line of tight junction ( TJ) and normal ultrastructure of BTB were observed .After Cd treatment ,the vesicular formation in the Sc was observed .The ultrastructural damage of Sc and TJ was observed .Compared with the corresponding time point of Cd group ,these were weakened in morphology of testis and ultrastructure of TJ after Cd +A or Cd +SB203580 treatment .The positive products of zonula occludens-1 ( ZO-1 ) and claudin-11 were localized mainly in the base of the seminiferous tubule .After Cd treatment , the average absorbance (AA) of ZO-1 and Claudin-11 was decreased significantly compared with that of the control group (P<0.05).After Cd +A or Cd +SB203580 treatment,AA of ZO-1 and Claudin-11 were increased significantly compared with that of the Cd group(P<0.05),though lower than that of the control group .The result of Western blotting showed that phosphorylation-p38MAPK in Cd group was increased significantly compared with that of the control group (P<0.05).After Cd +A or Cd+SB203580 treatment, it was decreased significantly compared with that of the Cd group (P<0.05).Conclusion Cd decreases ZO-1 and Claudin-11 expression and damages ultrastructure of TJ in BTB , asⅣhas protective effect on it , and is related to inhibiting activation of p 38 MAPK pathway .

Objective To investigate the toxic effect of cadmium (Cd) on the ultrastructure ,expression of related protein and the signal molecule phosphrylated P38 mitogen-actived protein kinase(P-P38MAPK) of primary cultured rat sertoli cell(Sc) ,and the protective effect of astragaloside (A ) on it .Methods The primary cultured rat Sc were divided into the control group ,Cd (50 mol/L)group and Cd(50 mol/L) plus A(10 mg/L) group ,they were used for the electron microscope observation and the im-munohistochemistry detection of vimentin ,E-cadherin ,-catenin and P-P38MAPK .Results The Sc ultrastructural changes included that the swelled mitochondria ,abundant lipid droplets and dilated endoplasmic reticulum were found in the Cd group .Further ,apop-tosis occurred in some Sc .However these ultrastructure changes above mentioned were slighter in the Cd plus A group ;the immu-nohistochemistry showed that the positive products of vimentin ,E-cadherin and-catenin were obviously decreased in the Cd group (P<0 .05) ,and those in the Cd plus A group were higher compared with the Cd group(P<0 .05);the expression of P-P38MAPK in cytoplasm was increased in the Cd group ,and showed the trend to move from cytoplasm to nucleus ,meanwhile ,the positive prod-ucts expression in the Cd plus A group was lower than that in the Cd group (P<0 .05) .Conclusion Cadmium can cause the injury of the Sc ultrastructure ,damage of cytoskeletal protein and fibronectin ,and increase of P-P38MAPK level ;astragaloside can antago-nize the toxicity of cadmium on Sc ,the protective effect maybe related with the decrease of P-P38MAPK in Sc .