EFFECT OF THYMECTOMY IN RATS AND CALVES DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By EUGENE PAPP, D.V.M., M.Sc. The Ohio State University I960 Approved by Advise] Department of Veterinary Anatomy ACKNOWLEDGMENTS The author wishes to thank his adviser, Dr. W. G. Venzke, for his great aid and indispensable supervision, and Dean W. R. Krill of the College of Veterinary Medicine for his continuing interest and encouragement in this work. He is grateful to Dr. E. H. Bohl for his participation in the work with tissue cxilture. Thanks are due Drs. A. A. Gabel, R. L. Rudy, and W. J. Roenigk for their technical assistance in the field of surgery and to Dr. R. 0. Moore for his aid in the biochemical aspects of the problem. Gratitude is extended to Dr. M. Y . Andres for his technical assistance, to Mr. Bud Kramer for many of the excellent illustrations which appear in this dissertation, and to Mr. D. 0. Oliver for his aid in the preparation of the manuscript. Gratitude is extended to contributors to the Development Fund of Ohio State University. Finally, the author thanks his wife, Mrs. Helen Papp, both for her technical help and her forbearance. ii TABLE OP CONTENTS Chapter Page Introduction ..................... .... 1 Review of Literatiire...................... h. Developmental A;natomy................ 1+ Gross Anatomy........................ 5 Histology ............................ 6 Cytology .......................... 11 Reticulum C e l l s ................ 11 Thymic Lymphocytes.............. 13 Myoid C e l l s .................... 16 Hassall's Bodies ................ 17 Plasma Cells, Granulocytes, and Mast C e l l s .................. 19 Biochemistry of the Thymus ..... .20 Hi stones........................ 20 Protamines...................... 20 Lipoproteins .................... 21 E n z y m e s ........................ 21 Peptide .................. 22 Cholesterol.................... 23 Vitamins........................ 2lp Involution of the T h y m u s ............ 25 Hypertrophy and Hyperplasia .......... 31 Thymectomy.......................... 32 Irradiation.......................... 31+ Augmentation and Substitution .... 36 Experiment 1 .............................. 1+1 Part 1 .............................. !).l Part 2 .............................. 1+6 Experiment 2 .............................. 51+ Experiment 3 .......................... 69 Part 1 .............................. 69 Part 2 .............................. 73 Experiment 1+....................... 87 iii Chapter Page Experiment 5>................................. 93 Part 1 .............................. 93 Part 2 ................................. 100 Part 3 ................................. 10l|. Part ij......................... Ill Part 5 > ................................. 116 Part 6 .......... ,.................. 13£ Experiment 6 ................................. lJ+7 Experiment 7 ................................. 15>6 Experiment 8 ................................. 161 D i scus sion ................................... 170 S u m m a r y ..................................... 183 Bibliography................................ 187 Autobiography . ...................... 201 iv LIST OP TABLES Table Page 1 Hemogram in Intact Rats as a Function of A g e ......................................... £8 2 Weekly Concentrations of Certain Blood Constituents in Intact R a t s ................ $9 3 Hemogram in Intact Calves as a Function of Age '..................................... 60 I). Weekly Concentrations of Certain Blood Constituents in Intact Calves .............. 61 5 Weekly Concentrations of Certain Ions in the Blood of Intact C a l v e s ................ 62 6 Effect of Thymectomy on Numbers of Leuco­ cytes Per Cubic Millimeter of Blood Before and After Splenectomy .............. 96 7 Effect of Thymectomy on Numbers of Lympho- cytes Per -Cubic Millimeter Before and After Splenectomy . ................... 97 8 Effect of Thymectomy on Numbers of Segmented Neutrophiles Before and After Splenectomy........................... 98 9 Effect of Thymectomy on the Hematocrit Value in Rats Before and After Splenectomy................................. 99 10 Effect of Splenectomy on Numbers of Leuco­ cytes Per Cubic Millimeter of Blood in Thymectomized and Control Rats ............ 101 11 Effect of Splenectomy on Numbers of Lympho­ cytes Per Cubic Millimeter of Blood in Thymectomized and Control Rats ....... 102 v Table rage 12 Effect of Splenectomy on Numbers of Segmented Neutrophiles per Cubic Millimeter of Blood in Thymectomized and Control R a t s ............. 103 13 Effect of Hypophysectomy With or ’Without Thymectomy on Numbers of Leucocytes Per Cubic Millimeter of Blood on R a t s ............. 106 lk Effect of Hypophysectomy With or Without Thymectomy on Numbers of Lymphocytes Per Cubic Millimeter of Blood in Rats ...... 107 15 Effect of Hypophysectomy With or Without Thymectomy on Numbers of Segmented Neutrophiles Per Cubic Millimeter of Blood in R a t s ............................ 108 16 Effect of Hypophysectomy ‘With or Without Thymectomy on Hematocrit of R a t s ........... 109 17 Effect of Hypophysectomy With or Without Thymectomy on Body Weight of Ra t s ........... 110 18 Organ Weights in Thymectomized and Intact Calves on January 8, i9 6 0 .................... lklj. vi LIST OP ILLUSTRATIONS Figure Page 1 Transverse serial sections of thymus of three day old rat H and E. x L|7£.......... 50 2 Transverse serial sections of .thymus of three day old rat H and E. x l\.j5 .... 5>2 3 Parabolic regression of second degree based on blood samples drawn three times weekly from rats of group A . 63 k Parabolic regression of second degree based on blood samples drawn two times weekly from rats of group B . 6£ 5 Parabolic regression 'of second degree based on blood samples drawn once weekly from rats of group C ............ 67 6 Thymectomy of the rat. Splitting of the sternum before the removal of the thymus gland . ....................... 77 7 Split sternum up to the third sternal cartilage. Exposed thymus gland in the r a t .............................. 79 8 Removal of the thymus gland in the rat with the help of blended scissors and forceps .............................. 81 9 Exposed mediastinal region in the rats after thymus gland was re m o v e d ......... 83 10 Cross suture with cat-gut closing the split sternum and the mediastinum .... 11 Testicular and body weights of thy­ mectomized and intact rats as a function of a g e ........................ 112 vii Figure Page 12 Spleen and body weights of thymectoralzed and intact rats as a function of age . 112 13 Adrenals and body weights of thymecto­ mized and intact rats as a function of a g e ............................ lli(. llj. Cervical lymph node of a thymectomized littermate rat 22 days following operation H and E. x 1 0 0 .......... 118' 15 Cervical lymph node of an intact litter- mate of the same age as above. H and E. x 1 0 0 .................... ................ 118 16 Bone marrow of an thymectomized rat 22 days following operation. H and E. x 1x7 i? .......... ..................................... 1 2 0 17 Bone marroxtf of the above intact litter- mate of the same a g e .............. 120 18 Adrenal cortex of a thymectomized rat 22 days following operation. H and E. x h i S ........ ............................ 123 19 Adrenal cortex of an intact littermate of the same age as above. H and E. x hlS ....................... 123 20 Testis of a thymectomized rat SO days following operation. H and E. x [(.75 . • • 126 21 Testis of an intact littermate rat of the same age as above. H and E. x h7S • • 126 22 Kidney of a thymectomized rat of SS days following operation. H and E. x hlS • • • 128 23 Kidney of an intact littermate ra.t of the same age as above. H and E. x hlS .... 128 2l| Spleen of a thymectomized rat 28 day^s following operation. H and E. x hlS . • . 130 25 Spleen of an intact littermate rat of the same age as above. H and E. x hlS .... 130 viii Figure Page 26 Liver of a thymectomized rat 28 days following operation. H and E. x 1+75 . • 132 27 Liver of our intact littermate rat of the same age as above. Ii and E. x i+75? • • 132 28 Testis of the thvmectomized calf Sq_ born M a y 2 k , 1959 li-j.l 29 Testis of the intact calf S>2 Lorn June 17, 1959......................................... • li*l 30 Comparison of weights between calves 115 and 111+; Hi and H2; Si and S2; ?i and ?2 .’ 11+5 31 Thymus of the rat exposed to., whole-body irradiation of 150 r and removed on fifth day following tumor implantation H and E. x 1350 ............ 165 32 Thymus of an other rat exposed to whole- body irradiation of 150 r and removed on fifth day following tumor implantation. H and E. x 1350 .......................... 165 ix INTRODUCTION Jacob Berengar of Carpi (died l£50, quoted after Singer) (li^.6 ) was the first to give a clear account of the thymus. Since that time the thymus has attracted increasing interest among many investigators, and the majority of them have left the problems without’ determining its function. A solution to the problem of function of the thymus must be considered far from being solved. Some authors have ascribed an endocrine function to the thymus (e.g. Bomskov, (II4.), Comsa (33), Schmincke (llf.2) Lowenthal (101 )3 , while others do not regard this organ as a hormone-producing gland (e.g. Bargmann (9), Hammar (63)J. Metcalf (110), Bomskov (168), Metcalf and Buffett (ill), and Comsa