The Influence Of Liquid Nitrogen Cryopreserved Method Ameliorated By HTK Solution On Tissue Viability Of Valved Conduit In Rat

Objective: To investigate the influence of liquid nitrogen cryopreserved methodameliorated by HTK solution on tissue viability of valved conduit in rat.Methods: Seventy SD rats were divided into7groups randomly, valved conduitswere acquired from each rat.(1)Control group: Each valved conduit was testedwithout sterile incubation.(2)Group A: Each valved conduit was incubated in anantibiotic nutrient solution made of antibiotics and RPMI1640culture medium.(3)Group B: Each valved conduit was incubated in an antibiotic nutrient solutionmade of antibiotics,50%RPMI1640culture medium and50%HTK solution.(4)Group C: Each valved conduit was incubated in an antibiotic nutrient solutionmade of antibiotics and HTK solution.(5)Group D: Each valved conduit wasincubated as Group C, then cryopreserved in cryoprotectant made of70%RPMI1640solution,20%fetal calf serum and10%DMSO.(6)Group E: Each valved conduit wasincubated as Group C, then cryopreserved in cryoprotectant made of35%RPMI1640solution,35%HTK solution,20%fetal calf serum and10%DMSO.(7)Group E:Each valved conduit was incubated as Group C, then cryopreserved in cryoprotectantmade of70%HTK solution,20%fetal calf serum and10%DMSO.All valvedconduits were tested in bacteriological examination, cytoactive examination andhistology determination. Alpha-ketoglutaric acid was deceted in Group C, Group D,Group E and Group F.Results: Eumycete and bacteria was not detected in any valved conduit in each groupafter sterile incubation. Except the control group, cytoactive and extracellular matrixof valved conduit were protected best in group C. During the period of sterileincubation, the content of alpha-ketoglutaric acid was decreased as time extended.However, during the cryopreserved period, There was no significant difference onpreservation of valved homograft conduit of each experimental group..Conciusion: During the period of sterile incubation, the effect of luquid nitrogencryopreserved method in protecting cytoactive and extracellular matrix of valved conduit in rat can be improved by HTK solution. The two possible mechanism aretryptophan and alpha-ketoglutaric acid can provide energy to valved conduit as energysubstrate, and histidine buffer can effectively keep the intracellular and extracellularenvironment stable. However, due to the stagnate of cellular metabolism, theprotective mechanism of HTK solution can not be fully take into effect, tissuepreservation mainly depends on cryoprotectants and cryopreservation rate controlduring the cryopreserved period.