It is well known that interleukin-2, a kind of lymphokine produced by the lymphocytes stimulated by antigen or mitogen, mediates antitumor effect by stimulating the proliferation of helper and cytotoxic T-cells, augmenting the tumorlytic activities of natural killer cells and promoting the differentiation of precussor T-cell into lymphokine activated killer cells in vivo.´ Thus, interleukin-2 is widely used as immunotherapeutic agent on various sarcoma and carcinoma and it also regresses the metastasis of malignant tumors.
Although interleukin-2 is very beneficial to cancer patients, it also develops many side effects including fever, chillness, general malaise, mental confusion, vomiting, diarrhea, hepatic and renal dysfunction, and capillary leakage syndrom (such as general edema, heavyweight gain, ascites and pulmonary edema) limiting the clinical use of interleukin-2. In this experiment, the author pursued the effect of interleukin-2 on the ultrastructure of the colloidal cell of the mouse thyroid.
Thirty healthy male DDY mice, weighing about 20 gm, were used as experimental animals. The experimental animals were divided into the control groups and the experimental groups and then the interleukin-2 treated mice were subdivided into 3 hours, 6 hours, 12 hours, 24 hours and 48 hours groups by intervals of time after administration and allocated 5 mice to each group. The experimental animals were treated with 2 million unit interleukin-2/0.2ml per kg of body weight in interleukin-2 treated groups and with 0.2 ml of normal saline per kg of body weight in the control groups. And animals were sacrificed at intervals of 3, 6, 12, 24, and 48 hours after administration. The specimens, thyroid gland obtained by thyroidectomy, were prefixed in 2% glutaraldehyde-2.5% paraformaldehyde solution buffered by Millorning´s phosphate buffer (pH7.2) for 2-4 hours and postfixed in 1% osmium tetroxide buffered by same buffer solution of 4C for 2 hours. After dehydration, the specimens were embedded in Epon 812 and then ultrathin sectons, 600-800A in thickness, were made with LKB V ultramicrotome. These preparations were stained with uranyl acetate and lead citrate and observed with JEM 100cx-II electron microscope.
The results obtained were as follows:
1. Cisternae of rough endoplasmic reticulum were markedly dilated and distruption of a number of cisternae of rough endoplasmic reticulum accompanied with dissocia
Lion of membrane bound ribosome were observed.
2. Some of mitochondria containing whorled membranous body and deletion of mitochondria) matrix was observed.
3. Cisternae of Golgi complex were dilated and numbers of secretory granule were reduced in number.
4. Autosomes containing whorled membranous body and other membranous structures were observed.
Based on the results obtained in the present study, it is suggested that interleukin-2 would induce the changes of ultrastructure of colloidal cells in mouse thyroid.
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