Detection of apoptosis in experimentaly induced fibrosarcomas using dna fragmentation and immunohystochemical methods

Fibrosarcoma is driving from mesenchimal tissue. It is one of the malign tumors and usually seen in cats and dogs, however, itcan be encountered in all animals. It is growing quite fast and invade in other tissue rapidly. It is one of mesenchimal tumor in rodents varying between 1-3 %, and in rat 1-6 %. Apoptosis used for eliminating of cells which are functioning not properly. Early diagnosis of tumors and follow up prognosis are of great impotance for extention of live of cancer patients. Especially, fibrosarcoms in cats occur in vaccation areas due to the chronic inflamatio. Recent studies on tumors showed that there is a connetion between cancers and apoptosis. In this study apoptosis in fibrosarcomas induced by 3- methylcholantrene with two different methods. Thus relationship between apoptosis and fibrosarcomas is investigated. On the other hand programmed cell death investigated using immunhystochemical and ELISA methods and differences in results are compared. Sixteen male Spraque Dawley rats used in this study. They were 8 weeks old and the body weights of the rats were between 150-200 grams. Rats were allocated into two groups each containing 8 rats. During the experiment which took between 150-210 days depending on the appearance of tumor tissue. They were allowed free access to water and feed. In order to induce fibrosarcoma in rats, at the beginning of the experiment animals were injected subcutaneusly on the neck with 0,2 mg 3-methylcholanthrene solved in 0,25 ml sesame oil. To find out weather any tumoral tissue occured animals were palpated daily. At the end of the experiment animals were killed under the ether anesthesia and necropsy is permormed. DNA fragments of tumor tissue cell were analized using ELISA (Roche), localisation of Bcl-2 and Bax was determine by immunohystochemically method. Tissues obtained from the control and the experimental animals homogenizated, centrifugated and the supernatant was used for ELISA procedure. In experimental group absorbance of the DNA fragmentation was 0,262 U but in control group it was 0,069 U. In other words absorbance of DNA fragmentation of experimental animals was 4 times higher than that of controls. Immunohystochemically there was a lot of Bcl-2 and Bax positive cells. Contrary to this in control animals there was hardly Bcl-2 and bax positive cells. This data indicates that in the tumor tissue it is observed some cells programmed to death by apoptosis but the others not. In the light of this findings we got in the present study apoptosis is encountered frequently in fibrosarcoma and fragmentation of the DNA indicates apoptosis. Researchers who are engageg in curing of cacer patients should take into concideration of levels of Bcl-2 and Bax proteins. Furthermore, smilar to the results of previous studies the rate of apoptosis seems to be very low at the beginning of the cancer however in the course of the time concomitantly the increase in proliferation of the tumor cells the rate of apoptosis increased dramatically.