Abstract： Objective To explore the use of in vivo cryotechnique (IVCT) to study the effect of injection of exogenous serum albumin ( bovine serum albumin,BSA) on immunoglobulin distribution into intercalated disc of mouse heart.Methods The experiment was divided into control group,BSA (concentration of 100 mg/ml) injection (5 min group,30 min group,and 4 h group,respectively),and BSA ( concentration of 4 mg/ml) injection of 4 h group.In vivo cryotechnique and freez substitution were utilized in each group of mice heart,respectively.Hematoxylin eosin (HE) staining,serum albumin,immunoglobulin,and Connexin43 double immunofluorescence staining were prepared on continuous paraffin sections.Confocal microscopy analysis and statistical analysis were applied.Results After BSA injection 5 min,BSA was only immunolocalized in vessels.After BSA injection 30 min,BSA was immunolocalized in vasculature,interstitium,intercalated disc,and T tubules,the same as endogenous serum albumin distribution.Comparing with low concentration of BSA (4 mg/ml) injection,after high concentration of BSA ( concentration of 100 mg/ml) iujection 4 h,IgG was abnormally immunolocalization in the intercalated disc.Conclusions The intravenous injection of exogenous serum albumin BSA,its distribution is the same as that of endogenous serum albumin.The intravenous injection of high concentrations of exogenous serum albumin BSA can cause the immunodistribution change of autoimmune serum immunoglobulin,and the change of myocardial extracellular microenvironment.