Biblioteca Virtual en Salud

BACKGROUND:

Under the pathological conditions of urethral defect,stricture and diverticulum induce by trauma,congenital malformation,tumor and operation,autogenous tissue are used for defect repair.

OBJECTIVE:

To verify the feasibility of urethra constructed by tissue engineering.DESIGN,TIME AND

SETTING:

An observational experiment was performed at Linbaixin Medical Research Center,Sun Yat-sen University,from January 2005 to January 2006.MATERIALSTen New Zealand rabbits weighing 3.0-3.5 kg were used to prepare acellular urethras.Twenty BALB/cA-nude mice weighing 18-20 g,4-6 weeks old,were cultured with extracellular matrix materials in vivo.

METHODS:

The whole urethra harvested from New Zealand rabbit prepared the extracellular matrix materials by acellular treatment.Half a glans harvested from adult New Zealand rabbit was used for smooth muscle cells proliferation by tissue explant.The corpus spongiosum smooth muscle cells were implanted in acellular matrix materials.Then,they were cultured by subcutaneous embedding in nude mice.There were two groups in the experimentexperimental and control.The complexs of corpus spongiosum smooth muscle cells implanted in acellular matrix materials were embedded in the experimental group,while the simple acellular matrix materials were embedded in the control group.MAIN OUTCOME

MEASURES:

After 1,2,4,6,8 weeks of embedment,the growth of the complexs were examined by gross,histologic and electron microscopic observation.The expression of smooth muscle cells were identified by immunohistochemistry method.

RESULTS:

①Under the gross observation,incisions on the back of the nude mice healed well,the diets and activities of the nude mice were normal.In the experimental group,there were thin tissue membranes on the surface of the acellular matrix materials at 1-2 weeks after the embedment.The thickness of tissue membrane increased gradually and there were small blood vessels grown at 4 weeks.The new cells were instead of acellular matrix materials at 6-8 weeks.②Under HE straining,the acellular matrix materials were absorbed.Various cells,most of them were smooth muscle cells,would be instead of the acellular matrix materials.And unequal blood vessels grown in matrix materials,most of them had the trend of blood sinus formation.These results suggested that the complexs formed the structure similar to normal urethra in the nude mice.③Under the electron microscopic observation,there were blood vessels grown in the matrix materials from 4 weeks after embedment.More smooth muscle cells,endothelial cells,and little fibroblast cells,macrophages were observed,as well as some apoptotic smooth muscle cells.④After immunohistochemical staining of ?-smooth-muscle actin antibody,the growth of smooth muscle cells could be observed.

CONCLUSION:

The corpus cavernosum tissue similar to normal urethra can be constructed by using tissue-engineering technique.