Essay, Research Paper: The Effects Of Tetracycline On Chick Embryos

THE EFFECTS OF TETRACYCLINE ON GALLUS DOMESTICUS TRIMESTER 3 Professor J. P. Ellis T.A. Tom Pinard Bryan Dumanski Mike Hale Dean Tower Heather Mammon Joe Hull July 15, 1996 Abstract Our Embryology lab experiment was performed to observe the effects of tetracycline on the development in chicken embryos, such as bone and beak growth. Five control and seven experimental eggs were used for the experiment. The five control eggs were not injected with tetracycline, six of the experimental eggs were injected with 0.05 mg of tetracycline, and one of the experimental eggs was injected with 0.2 mg of tetracycline. On the seventeenth day of embryo development, all eggs were opened and observed. Good conclusive results were noted. Out of the seven injected eggs, all had some sort of abnormality. Conversely the control group eggs appeared normal. Table of Contents I. Introduction II. Methodology III. Results and Observations IV. Discussion and Conclusion V. Bibliography I. Introduction and Review Tetracycline, an antibacterial drug, is used to treat many infectious diseases such as gonorrhea, syphilis, sinusitis, upper respiratory infections. The usual adult dosage ranges from 100mg to 200mg once a day. Possible allergic reactions include: 1) swelling of the face, 2) skin rash, 3) loss of appetite with vomiting, 4) soar throat, and 5) abdominal cramping. There are more serious side effects , such as anaphylactic reactions, liver and renal damage, discoloration of teeth with malformation in children under 8 years of age. Results of animal studies shows that tetracycline class drugs cross the placenta and are found in fetal tissues. This has toxic effects on developing fetuses. These effects include retardation of skeletal development, decreased white cells, and increased eosionophils. Due to the findings, it is advisable to completely avoid tetracycline class drugs during pregnancy and breast feeding. Tetracycline drugs are used specifically in chick embryos autoradiographic studies. The chick's bones have the ability to fluoresce tetracycline at the active sites of calcification. Tetracyclines have effected not only chick embryos, but also weight and bone formation in the offspring of rats and mice. It causes reduction in fetal size with serious physical defects. II. Methodology The effect of tetracycline infections were demonstrated on twelve New Hampshire Red Chicken eggs. The control group included five eggs numbered eight through twelve and were not injected. The injections were given on June 12, 1996 to seven eggs numbers one through seven. Eggs one though six received 0.05mg of tetracycline and egg seven was given an increased amount of 0.2mg tetracycline. All of the eggs were incubated at an ideal temperature of 101 degrees, sixty to eighty percent humidity in the incubator (model no. 624-E) for seventeen days. The eggs were turned twice daily before being sacrificed on the seventeenth day June 28, 1996. III. Results and Observations Experimental Group Amount of Tetracycline injected Eggs Number Embryo Weight No fertilization, pseudo white masses, no development 0.05mg 1 N/A Twice as large as control group, no malformations 0.05mg 2 23.8g Twice as large as control group, slightly malformed feet 0.05mg 3 22.5g Twice as large as control group, no malformations 0.05mg 4 22.0g Twice as large as control group, no malformations 0.05mg 5 22.5g Twice as large as control group, no malformations 0.05mg 6 20.95g Twice as small as control group, not fully developed, internal organs exposed, malformed legs, dead 0.2mg 7 16.9g III. Results and Observations (con't) Control Group Amount of Tetracycline injected Eggs Number Embryo Weight Normal development, medium size N/A 8 18.6g Normal development, medium size N/A 9 18.8g Not fertilized; pseudo white masses present N/A 10 N/A Normal development, medium size N/A 11 19.3g Not fertilized;pseudo white masses present N/A 12 N/A IV. Discussion and Conclusion The results of the experiment were compared and found to be conclusive. Distinguishing characteristics were noted between the control group and the experimental group which included size of embryo, overall weight, feather growth, and bone development. Internal development was not observed in this experiment. Weights of embryos two through six injected with 0.05mg of tetracycline were: 23.8g, 22.5g, 22.0g, 22.5g, and 20.95g, respectively. These embryos appeared to be abnormally larger than the control group embryos. Embryo number three also had external defects; malformed legs. We also noted that all of these embryos had more feather growth than the control group. Embryos number seven, injected with 0.2mg of tetracycline showed the most dramatic results. This embryo was smaller and weighed significantly less than the other experimental embryos (16.9g). In addition, the external organs were exposed, there was no feather growth and the embryo died during the experimental period. Our experiment found that three embryos did not fertilize (embryos 1, 10, and 12) and were not part of the conclusions. In conclusion, our experimental findings showed that tetracycline is inhibitive to normal embryo growth as found in embryos two through six. Further, higher dosages of tetracycline are detrimental to embryonic growth as noted in embryos seven. If future testing is done, more embryos should be injected at the higher 0.2mg dosage to validate the findings from embryo seven and an internal study of embryos two through six (with 0.05mg tetracycline) should be conducted to determine possible contributing factors to the abnormally large growth of these embryos. . V. Bibliography Beckman, D., Brent, R., Mechanisms of Teratogenesis, Ann Rev. Pharmacol Toxicol, No. 24, p. 483-500. (1984) Greene, G.: Tetracycline in Pregnancy, New England Journal of Medicine, Vol. 295, No. 9, (1976) Halme, Jouko, Aer, J: Effect of Tetracycline on Synthesis of Collagen and Incorporation of Calcium into Bone in Foetal and Pregnant Rats, Biochemical Pharmacology, Vol. 17, p. 1479-1484. Hoolingsworth, M.: Drugs and Pregnancy, Clinic in Obstetrics and Gynecology, Vol. 4, No. 2, p. 503-520 (1977) Long, J., Rybacki, Doxycycline, The Essential Guide to Prescription Drugs, p. 461-464, (1994). Saivin, S., Houin, G., Clinical Pharmacokinetics of Doxycycline and Minocycline, Clinical Pharmacokinetics, No. 15, p. 355-366 (1988)