Endosulfan and N-nitroso-N-methylurea could cause hepatomegaly and kidney tumor in rats

Abstract

Aim / Background: Pesticides and nitrites which could be available in foods are generally investigated individually, although they could be found in foods together and exhibit combined health effects. In this study we aimed to determine the combined effects of endosulfan which is a commonly used pesticide and N-nitroso-N-methylurea (NMU) which is a prototype for mammary tumor development in Sprague Dawley rats and could be formed in brine foods or also in body from nitrites which is commonly used in meat. Method: Ninety female Sprague Dawley rats had been used. Animals were divided three groups which consisted 30 animals. The first group took a single dose endosulfan intraperitoneal (ip) on 19th day and a single dose NMU ip on 21 day, the second group took endosulfan by their drinking waters for the first 60 days of their life and a single dose NMU ip on 21 day, and the third group took only a single dose NMU ip on 21 day. Animals were controlled for their general health status, mammary mass development, daily water consumption and weekly weight gain. At the end of the study rats were examined carefully under anesthesia, and tissue samples were prepared from their mammary glands and intraabdominal organs. Tissue samples taken from mammary glands, liver and kidneys were histopathalogically examined. Results: It was determined a statistically significant hepatomegally in the second group when we compared to other groups (p < 0.05). No animals developed mammary tumors. On the macroscopic examination and manual palpation of intraabdominal region, it was showed that solid tumors in kidneys as a ratio of 76.7% of the animals in the second group (bilateral in 1,3% of them, the others are unilaterally and 70% of the unilateral tumors are in the left kidneys while the rest of them are right localized). Also it was found that in the first group, 13.4% of the animals developed unilateral kidney tumors. The third group which had been applied only NMU developed no kidney or liver pathology macroscopically. Conclusions: As a result it was considered that a diversity which is named as “genetic shift” could be developed in our animal research center and because of this shift we could not developed NMU induced mammary tumors in our Sprague Dawley rats. But it has been showed that long term endosulfan expose has resulted in kidney tumor development for the first time. Because of the genetic shifting mentioned above, it should be tested whether this experimental animal cancer model is limited for our research center or not by obtaining Sprague dawley animals from different centers. Consumers and appliers should be educated about using pesticides, and healthy and safety food production and consumption should be considered as one of the primary subjects in public health studies. * This article was prepared from doctorate (PhD) thesis of Dr. Recai Ogur (The effect of some pesticides, used in production of foods which consumed frequently by public, on the development of mammary tumors formed by nitroso compounds. Ankara. 2006).