Introduction

The objective of this study was to investigate the fatty acids (FA) content and composition in lipids extracts obtained from spontaneous tumor and corresponding nontumoral female dogs mammary gland.

Materials and methods

The samples of spontaneous tumor tissues were characterized from the pathologic standpoint [1]. We analyzed three different types of carcinosarcoma, alveolar carcinoma, adenocarcinoma and corresponding nontumoral tissues. Total lipids were extracted with chloroform: methanol (2:1) [2]. Fatty acids were separated by chromatography in gaseous phase (GC). The etherification of FA was carried out with boron trifluoride (BF₃) in methanol [3]. For the quantitative determinations, heptadecanoic acid (20 µl, 0.1 mg/ml) was used. For FA identification a mixture of standards of fatty acids (Sigma) was used.

Results

The main fatty acids determined in lipids extracts are: palmitic acid (16:0), stearic acid (18:0), oleic acid (18:1), linoleic acid (18:2) and arachidonic acid (20:4). Total fatty acid content appears to be lower in tumor compared with nontumoral tissues. For example in carcinosarcoma the content was 199, 50 µg/g tissue and in nontumoral tissue was 421, 5. In adenocarcinoma and alveolar carcinoma the content was higher compared (for example 311, 20 µg/g tissue in carcinoma and 348, 96 in adenocarcinoma) and compared with nontumoral tissues (411, 45 and 454, 56 µg /g tissue respectively).If we compared the content in different type of fatty acids we can observed that in al tumoral tissues palmitic, linoleic and arachidonic acids decrease and stearic and oleic acids increase compared with nontumoral gland. For example in alveolar carcinoma were: 84,72 µg 16:0, 54,08 µg 18:0, 73,60 µg oleic 18:1, 42,66 µg 18:2 and 56,18 µg 20:4 and in nontumoral tissue: 161,13 µg 16:0, 72,31 µg 18:0, 50,04 µg 28:1, 27,51 µg 18:2 and 1004,43 µg 20:4. The same pattern of FA was observed in all investigated samples.

Conclusions

Subsequent to the biochemical determination performed it was noticed that in tumors appears an accumulation tendency of saturated fatty acids (especially of the palmitic acid 16:0) and of the monounsaturated fatty acids (oleic acid 18:1), accumulation which may be explained by the intensification of the lipids metabolization, according to the need of tumoral cells to proliferate and multiply rapidly. In tumoral tissues the content of polyunsaturated acids is low as compared to saturated fatty acids and those monounsaturated, probably due their oxidation processes under the action of the oxygen reactive species.

References

1.  Baba A.I., 2002, "Comparative Oncology", Ed. Academia Romana

2.  Folch J. et al., 1957, J.Biol.Chem. 226:497-509

3.  Piintea A. et al., 2001, Phytochem. Anal. 12: 293-298