范文《轉(zhuǎn)基因大豆對(duì)幼鼠出生時(shí)體重和存活率的影響》對(duì)照試驗(yàn)性研究

1、Influence of Genetically modified Soya大豆 on the Birth-Weight and Survival of RatPups仔Abstract1 Investigation of the influence of GM soya on the birthrate and survival of the offspring后代of Wistar rats2 were performed. A group of female rats were fed GM soya flour beforemating 交配and pregnancy. The con

2、trol group of females were fed traditional soya andthe third group of females, the positive control group, received feed without any soya.The weight and the mortality死亡 rate of the newborn pups were analyzed. The studyshowed that there was a very high rate of pup mortality (55.6%) in the GM soya gro

3、upin comparison with the control group and the positive control group (9% and 6.8%respectively. Moreover, death in the first group continued during lactation哺乳, and theweights of the survivors are lower those from the other two groups. It was revealed inthese experiments, that GM soya could have a n

4、egative influence on the offspring ofWistar rats.Introduction2 The term genetically modified organism (GMO3s) refers to plants, microbes andanimals with genes transferred from other species in order to produce certain novelcharacteristics (for example resistance to pests, or herbicides) and are prod

5、ucedby recombinant DNA technology. Four main sources of the hazards危險(xiǎn) of GMO arediscussed by scientists worldwide: 1) those due to the new genes, and gene productsintroduced; 2) unintended effects inherent內(nèi)在的 to the technology; 3) interactions betweenforeign genes and host genes; and 4) those arisin

6、g from the spread of the introducedgenes by ordinary cross-pollination異花授粉 as well as by horizontal gene transfer (WorldScientists Statement 2000).3 GM crops contain material, which is not present in them under natural conditions,and they form a part of our daily diet. To understand what effect they

7、 can have on usand on our animals it is vitally important to study the influence of these GM plants indifferent organisms for several generations. At the present, these studies are lackingfrom the scientific literature. Also, several detrimental effects of GM crops had beenshowed on the metabolism o

8、f animals. The hazard of genetically modified organisms(GMO) was shown for animals and the environment in many investigations (Traavik1995; Ho and Tappeser 1997; Pusztai 1999 and 2001; Kuznetcov et al. 2004 and others).Earlier it was shown that consumption of GM food by animals led to the negativech

9、anges in their organisms. Experiments, conducted by A. Pusztai showed thatpotatoes modified by the insertion of the gene of the snowdrop lectin4 (an insecticidalproteins), stunted the growth of rats, significantly affected some of their vital organs,including the kidneys, thymus, gastrocnemius muscl

10、e and others (1998) and damagedtheir intestines and their immune system (Ewen and Pusztai 1999). Similar effect ofGM potatoes on rats was obtained at Institute of Nutrition in Russia (Ermakova 2005).4 It is put forward in the risk assessment documents that the GM components oftransformed plants are

11、completely destroyed in the digestive tract of humans andanimals, together with the other genetic material found in them. However, foreignDNA plasmids5 are steadier against the digestion than it was originally believed.Plasmid DNA and GM DNA were found in microorganisms of the intestine and insaliva

12、 (Mercer et al. 1998; Coghlan 2002). Experimental researches in mice showedthat ingested foreign DNA can persist in fragmented form in the gastrointestinal tract,penetrate the intestinal wall, and reach the nuclei of leukocytes, spleen and liver cells(Schubbert et al. 1994). In another research of S

13、chubbert et al. (1998) the plasmidcontaining the gene for the green fluorescent protein6 (pEGFP-C1) or bacteriophageM13 DNA were fed to pregnant mice. Foreign DNA, orally ingested by pregnant mice,was discovered in blood (leukocytes), spleen, liver, heart, brain, testes and other organsof foetuses a

14、nd newborn animals. The authors considered that maternally ingestedforeign DNA could be potential mutagens for the developing fetus. At the same timeBrake and Evenson (2004) analyzing the testis in mice as a sensitive biomonitorof potential toxic, didnt find negative effects of transgenic soybean di

15、et on fetal,postnatal, puber talor adult testicular development.5 There is a lack of investigations on the influence of GM crops on mammals, especiallyon their reproductive function. Therefore, it was decided that we undertake a studyto see the effect of the most commonly used GM crop on the birth r

16、ate, mortality andweight gain of rat pups, whose mother were fed diets supplemented with the Roundup-Ready soya, a kind of GM food.MethodsAnimals6 Wistar rats were used in the experiment. The animals were brought up to sexualmaturity on laboratory rat feed. When their weight reached about 180-200g,

17、thefemale rats were divided into 3 groups, and housed in groups (3 rat/cage), and keptunder normal laboratory conditions.7 The feeding scheme was as follows. Females in every cage daily received dry pelletsfrom a special container placed on the top of their cage. Those rats receiving soya floursuppl

18、ement, were given the soya flour in a small container placed inside their cage (20gx 40 ml water) for three rats and, so 5-7g flour for each rat every day.Experiment8 One group of female rats of 180-200g weight was allocated to the experimental group,and received 5-7 soy a flour/rat/day prepared fro

19、m Roundup-Ready soya, added tothe rat feed for two weeks. Another group females (3) were allocated to the controlgroup, but their diet was supplemented with the same amount of soya flour, preparedfrom the traditional soya in which only traces (0.08+ 0.04%) of the GM construct waspresent, most likely

20、 resulting from cross-contamination. We also introduced a positivecontrol group (in two cages: 3x3), which had not been exposed to soya flour. Thereforefemales have only got the standard laboratory feed without any supplementation,although it is acknowledged that the energy and protein content of th

21、is diet was lessthan in the other two groups.9 After two weeks on the diets all groups of 3 females were mated with two healthy malesof the same age, who have never been exposed to soya flour supplements. First theone, then the other male was put into the cage for 3 days. In order to avoid infection

22、of females, the sperm count and quality has not been determined. We carried on withfeeding the respective diets to all females during mating and pregnancy. Upon delivery,all females were transferred to individual cages, and the amount of soya supplementwas increased by an additional g for every pup

23、born. Lab feed and water was availablefor all animals during the experimental period. When rat pups opened their eyes andcould feed themselves (from 13-14 days of age), the daily dose of soya supplement wasincreased till 2-3g for every pup, although all rats had free approach to the soya. Allrats at

24、e their soya portions well. Organs of some pups were taken out and weighed.Statistical analysis10 The level of mortality was analyzed by the one-way ANOVA7, using of Newman-Keulstest8 for share distribution. The pups weight and its distribution were checked byMann-Whitney test9 and Chi-square10 in S

25、tatSoft Statistica v6.0 Multilingua (Russia).Results11 By the end of the experiment, from the 15 females included in the experiment, 11gave birth and produced a total of 132 rat pups. The 4 rats who became pregnant from6 females on the positive control diet gave birth to 44 pups (an average of 11 pu

26、ps/female), while the four females, from the six on GM soya flour supplemented groupsgave birth to 45 (11.3 pups/female), and 3 from traditional soya group33 pups (11pups/mother).12 Supplementation of the diet of the females with GM soya led to the death of 25 pups,out of the 45 born by the end of t

27、he third week of lactation, while during the sameperiod on the traditional soya supplemented diets only 3 pups died from 33. Themortality in the positive control group was also 3, but from the larger number of pupsborn, as it seen in Table 1. High pup mortality was generally characteristic for femal

28、esfed the GM soya flour (Table2).13 Among the pups from the females fed the positive control diet, 2 pups died duringthe first week, and 1 during the second week after delivery. All pups from femalesfed traditional soya flour died during the first week after birth. However, pups fromfemales fed the

29、GM soya flour supplemented diet kept dying during lactation period asit is evident from Table3.14 In two weeks after their birth the weight of pups (with SE) from the GM soyasupplemented group was less (23.95g±1.5g) than that of the pups of the positivecontrol group (30.03g±1.1g; p<0.00

30、5), or from the traditional soya flour supplementedgroup (27.1g±0.9g; p< 0.1). Since the number of surviving pups were so different, theweigh distribution of the pups were compared in Table 4. From the data it is evident,that 36% of the pups from the GM soya group weighed less than 20 g, in

31、comparisonwith the 6% in the positive control group, and with the 6.7% found in the traditionalsoya supplemented diet group (Table 4). Study of pups organs mass showed that theorgans of small pups from GM group were tiny in comparison with the same of othergroups except the brain mass (Table 5). Thi

32、s fact indicated that the pups from the GMgroup were the same age as others, but changes were occurred with the developmentof internal organs. Slight negative effect was found in the group which receivedthe traditional soya, but this effect was not significant. No mortality of females andsurvived yo

33、ung pups eating the GM soya flour supplemented diet was observed.Discussion15 The reproductive behaviour of female rats fed on standard laboratory feedsupplemented with soya flour prepared from either genetically modified soya ortraditional soya was studied to see the effect of the diet on pregnancy

34、, lactation and thegrowth of the rat pups. Since it is well established that raw soybean contains a numberof anti-nutrients, such as the lectins, trypsin inhibitors, etc. (Pusztai et al. 1998), andalso female hormone-like substances, it was thought to be necessary to compare thesedata also with thos

35、e from a positive control group when animals were not exposed toany soya flour supplementation.16 In order to understand the mechanism how this widely consumed GM crop exertsits influence on the reproductive performance of mammals and their offspring, itwould be necessary to perform complex research

36、es, including histological, genetic andembryo-toxicological investigations. However, we had to restrict our experiments onlyfor a short time-span, and starting to feed the female rats two weeks before mating.However, unlike the experiments of Brake and Evenson (2004), who started to feedpregnant mic

37、e, in our experiments the diets supplemented with GM or traditionalsoya flours were already given to the female rats 2 weeks before mating already, and wecontinued to treat them with their respective diet until the pups were weaned.17 Upon delivery, very unexpectedly a very high rate of pup mortalit

38、y (55.6%) wasobserved in the the group of females whose diet was supplemented with the GMsoya flour in comparison with the pups of both the positive control (6.8%) andthe traditional soya flour supplemented (9%) groups. Also, in this group the pupscontinued to die over the period of lactation, which

39、 occurred only in the GM soya fedgroup. At the same time, the weights of the surviving rat pups were also lower. It is themore surprising, since the pups were smaller, about half, therefore more milk shouldhave been available for the individual pups. They should have a better chance to growoptimally

40、, unless the amount, and/or the quality of the milk were not affected byconsuming the GM soya flour.18 Our data allow us to speculate and presume that the negative effect of GM soya on thenewborn pups could be mediated by two possible factors. Firstly, it can be the resultof transformation, and inse

41、rtion of the foreign genes, which could enter into thesexual/stem cells, or/and into cells of the fetus, as it was observed by Schubbertet al. (1998). Secondly, negative effect of GM soya could be mediated by theaccumulation of Roundup residues in GM soya residues. However, no mortality wasobserved

42、with female rats, nor with the young pups survived, although they also beganto eat the GM soya, it is supposed that the effect could be mediated by the two firstfactors. (2,086 words)ReferencesBrake DG and Evenson DP (2004). A generational study of glyphosate-tolerantsoybeans on mouse fetal, postnat

43、al, pubertal and adult testicular development. FoodChemistry and Toxicology, 42: 29-36.Coghlan A (2002). GM crop DNA found in human gut bugs. New Scientist. 2002.Ermakova IV (2005). Conclusion to the report about feeding of rats by geneticallymodified potatoes Russet Burbank Agrarian Russia 2005. 62

44、-64.Ewen SW, Pusztai A (1999). Effect of diets containing genetically modified potatoesexpressing Galanthus nivalis lectin on rat small intestine. Lancet 354 (9187).Ho MW and Tappeser B (1997). Potential contributions of horizontal gene transfer tothe transboundary movement of living modified organi

45、sms resulting from modernbiotechnology. In Transboundary Movement of Living Modified Organisms Resultingfrom Modern Biotechnology: Issues and Opportunities for Policy-Makers (K. J.Mulongoy, Ed.) InternationalAcademy of the Environment, Switzerland:171-193.Kuznetcov W, Kulikov AM, MitrohinIA and Cidendambaev VD (2004). Geneticallymodified organisms and biological safety. Ecos 2004