Quantitative studies of the testicle. II. Pattern and total tubule length in the testicles of certain common mammalsкод для вставкиСкачать
QUANTITATIVE STUDIES O F THE TESTICLE 11. PATTERN AND TOTAL TUBULE LENGTH IN THE TESTICLES O F CERTAIN C O M M O N MAMMALS K. 3’. BASCOM AKD H. L. OSTERUD Medical College of Virginia INTRODUCTIOK Studies of the morphology of the testicle have been largely qualitative in character. Quantitative data, however, exist with reference to gross weight, tubule diameter, tubule length, and cell counts. As examples may be mentioned the work of Bouin and Ancel, Hatai, Jackson, Massaglia, Latimer, and Ressesen and Carlsoii, who have rocordecl gross weights of the testicles of various animals. Siperstein, in addition to gross weights, also gives the diameter of the seminiferous tubules and diameter of nuclei of interstitial cells. Moore, in a later paper on experimental cryptorcliidism, gives gross weights and tubule diameters. T.l.Tatson records seasonal changes in testicular diameter in the green finch. Riddle off’ers data on size and length relations in the right and left testes of the pigeon. Rasmussen, in his study of the seasonal changes in the marmot, employed cell counts of interstitial cells and records percentage weights of the testicles. Lengths of individual tubules were determined in the mouse, rabbit, and dog by Curtis. Huber and Curtis, writing on the seminiferous tubules in mammals, mention in an incidental way some quantitative data as to tubule length. Cunningham’s Nanual of Practical Anatomy, without citing the source of information, makes the statement that the human testicle “~onsists of four to six hundred fine hairlike , each of which is ahout 60 em. (two feet) long.” tuhcs 169 160 I<. F . RASCOM AND H. 1,. OSTERUI) To our knowledge, no quantitative method has been applied to the measurement and comparison of total tubule length of the seminiferous tubules in a series of laboratory ant1 domestic animals. I n this paper such a method and the results of its application are set forth. MATERIALS APU’D METHODS Total tubule lengths of single normal testicles were computed for the following species: albino mouse, albino rat, Guinea pig, cat, Belgian hare, dog, man, pig, sheep, and bull. T h c ~testicles were separated from the cpididymis and other extraneous tissue and were weighed in the fresh condition 1wfor.e fixation. I n tlic case of certain representative testicles of the bull and pig, the tunica albuginea was stripped off and the mediastinum dissected out in the fresh condition and w-ciglied separately from the rest of the testicle. Bouiri’s fluid was used in general as the fixative, Zenker’s fluid and 10 per cent formalin in a few cases. The testicles of the mousc’, rat, Guinea pig, cat, hare, and dog were fixed for a brief interval entire and then sliced with a razor for further fixation. From the larger testicles blocks of tissue were removed with a razor and fixed. Both celloidin and paraffin were used for embedding, the former, to the greater extent, proving also the more satisfactory. The combination of stains most frequently used was hematoxylin-eosin. The quantitative technique employed for determining total tubule length may best be presented by following successive steps in two typical examples. E ~ a n a p l e 1. Hull iesticle X 3. Fresh weight, 274 grums By the steps previously outlined it was determined that the tnnica albuginea and mediastinum weighed 15.5 grams (5.6 per cent of the total weight of this testicle). Hence tubules and interstitial t weighed 258.5 grams. Several representative fields in sections of this testicle were projected with an Edinger drawing apparatns and the tubules drawn in outline. Then the relative amounts of tubules and interstitial tissue present in these drawings were measured in two ways: by QUANTITATIVE STU1)IES OF T H E TESTICLE 161 use of a polar planimeter and by the paper method already employed by Baseom in estimating the amounts of interstitial tissue in testicles of swine. In testicle X 3 the relative percentages of tubules and interstitial tissue were, respectively, 83.9 per cent and 16.1 per cent. Since, as already stated, tubules and interstitial tissue together weighed 258.5 grams, according to the above percentages the testicle was calculated to contain 216.88 grams of tubules. For all practical purposes the specific gravity of fresh tissue may be taken as 1.0, hence the 216.88 grams of tubules are assumed to be very nearly equivalent to a volume of 216.88 cc. or 216,880 cu.mm. By means of a microscope with eyepiece micrometer, the average diameter of fifty seminiferous tubules was found to be 0.238 mm. Using the formula rr2, the average cross-sectional area of the seminiferous tubules was calculated to be 0.0446 sq.mm. Dividing total tubule volume in cubic millimeters (216,880) by cross-sectional area in square millimeters (0.0446) gives the total tubule length of this testicle in millimeters (4,862,000). This sum is more compactly expressed as 4862 meters or as 4.862 kilometers. Eza.nzple 2. Guinea-pig testicle X .I2A. Fresh weight, 1.2423 gmms In this case the tunica albuginca and mediastinurn could not conveiiient.ly be dissected away in the fresh condition. Representat.ive transverse sections from different, parts of the testicle were prepared. Ry means of the Edi.riger apparatus, a drawing was made from 'one of these sections and, with the aid of the planimeter, the percentage of mediastinum present was calculated (8.89 per cent). This was assumed to be the percentage of mediastinum in this testicle. The volume of tunica albuginea was det,ermined i n a different way. Its thiclrness was measured with a n eyepiece micrometer and found to average 0.031 mm. The Guinea-pig testicle approaches the spherica.1 form rather closely. Accordingly, testicle X 12 A was assumed t o be a sphere having a volume of 1.2423 cc., or 1242.3 cu.mm., t.he volume assumed to be equivalent to the weight of this testicle. The volume of a sphere equals &, hence a sphere of the above volume has a radius of 6.668 mm. The thickness of the tunica albuginea (0.031 mm.) subtracted from t.his ra.dius gives 6.637 mm. as t.he radius of the smaller sphere, wit.h a volume of 1223.6 cu.mm., representing t.ubules and interstitial tissue and mediastinurn. The percentage of mediastinum in t.his testicle, calculat.ed as shown above, was 8.89 per cent, equivalent to 110.4 cu.mm. Hence t.he net volume of t.ubules and int.erstit.ia1tissue becomes 1223.6 minus 110.4, or 1113.2 cu.mm. Of this volume 91.83 per cent, or 1022.25 cu.mm., was seminiferous tubules, determined as in example 1. Average t,ubule diameter was determined by micrometer measurement to be -:. 162 K. F. BASCOM AND H. L. OSTERUD 0.244 mm. Employing the formula d, the average cross-sectional ar~lais 0.0467 sq.nirn. Dividing volmne of tnbules (1022.2,?) by (.row-sectional area (0.0467) therefore gives 21,889 inin., o r 21.889 iiictcr-s as the total Inbule length in this testicle. We believe these two examples sufficiently illustrate the methods by which the results to be set forth in this paper were obtained. Corrections have not been made and could not easily be made f o r certain minor. errors, such as assuming tlic (lninea-pig testicle to be pcrfectly spherical, assuming the specific gravity of the testicle i o be 1.0, or assuming that all elements of the testicle shrink equally under such technical treatment as we have employed, but we do not believe that they substantially affect our result.' Tlianks are due A h . IIermari Neltori for tec2mical assistance. RESULTS The iiumerical data obtained by the above methods are summarized in table 1. 1)IBCTJSSlOA la table 1 the column of gross weights of testicles sl~ows great variation in weight in the cliEcrcnt species-from 0.0556 gram in the mouse to 367 grams in a boar. I n view of this great ciisparity in testicular weights, it is interesting t o fiud that the diameters of the tubules in the above-mentioned testicles are, respectively, 0.191 mm. and 0.223 mm.-a cliffcl*'All ctilculations as t o perceiiinge composition a r e based on the p1:ininwtrr method for the sake of uniformity and because we believe it t o be more accurate tliiin the piper method. We hare also found it t o be more rapid and less tedious. Results obtained by applFing both methods to each of twenty-six testicles of :~nimals of ten different species show a n :iver:rge discrepancy between the two scts of resultx of 3.45 per cent, figures olitained with the planimeter metliotl 1)csing on tlic :ivcr:igc sliglitly Iiiglier t1i:in those woykerl out by tlie paper metlioil. T n the first p:ipcr of this series (B:iscom, '2.5) no :illow:mce \\:IS m:ittr for tunic1 :ilbugine:i and medi:istiiiuni in ciilcn1:tting the amounts of tubules :ind i n t c w t i h l tissue m i pig testicles. 1lel:itive peiwntnges of tubules and interstitial I k s u e :ire not affected I)? this error, but :tbsolute weights of these clcinents as gi\cn i t 1 that picper are :il,ont 8 per cent too large. 16.3 QUAKTITATIVE STUDIES OF THE TESTICLE TABLE I - _. .. . Albino mouse SL 1 M2 I ;Ii 3 Albino mt 1 It1 li 2 3* 1C SA ' x K 3B K. 11 (;oillea pig s 1IA s 11B s 12.1 s 1211 0 .chi56 0.0Mfi 0.0746 0.0477 0.0321 0.0641 0.191 0.191 0.2008 0.0286 0.0286 0.0316 1.67 1.82 2.03 1.2% 1.13 0 . m 1 .-"497 1.288.3 1 .0283 1.a584 0. !I834 0.2422 0.248 0.0458 0.2"48 1 .087.5 1.1414 0 .9031 0.1652 0.2494 0.2589 0.2654 23.1 20.3 10.55 2 2 , :3 21.i 16.3 I .ti4 1 .493 1.5074 I .0222 0.9794 1 .0:31 I .W3B 1.7160 0.197!) 0.2084 0.244 0.2391 0.2262 0.231 A 0. Y3i9 0 . ;imi 0 .titi'25 0.1 7%; 0.1806 1.8556 0.183; 0.07 1.67 1,2m 1 .1 (itE 1 . 1ti& 1,1846 1.9!E%5 S 13A s 1311 s 20 Cat s lA* s 113" 0.8 0.94 Belgian 1i:irc x in 2.307 0.1075 s I!)* , I 0 . 1193 0.0484 0 . 0 2 13 0.0487 0. aw 0.0533 0.0307 o.o:x39 ().CCz(ji 0.0448 0.0402 0. ot2 0.0443 0.CMi4 I).0037 48.6 44.4 21.8!) 21.8 2,j.f i 24. r; 38.7 70.2 3L.2 I)0g s "h x 21i ti.5 137. 8 167.7 12.21 244'3.7 6.0 I 218.0 M i .O 15.0 89.0 1 (it\ ,o 125.29 246. 18 3 1 64 63 1 2 10.2113 70.44 129.4s 1092 41 19 37.53 2lti.88 4862 4LMl 4814 :3::19 lti4 I<. F. BASCOM A N D H. L. OSTRKUI) ~ i i of ~ eonly 14.3 per cent. Rat testicle R 11 had a greater tuhulc diameter (0.2654 mm.) than writs foiiiid in an>- other t eslicle stutlicd, not excepting even those of thc hoar, bull, o r ixm. The smallest a r e m g c tubnle diameter in the adult mas found in the human testicle X 10 (0.1834 mm.). The maxiniiirn vnr*iatioii ill tixhnle diameter iii this series of testicles is t l i e I 1 , i l l rouiitl iiumhers, 30 per cent. There is no direct rclatjoilship hettvceii tubule diameter arid the size of the adult ti~iimnlso far as our evidencv goes. TABLE 2 i fil'EU1r:s ... . . . .~~ ! ~ hIo11se .................. Kilt (adr1lt) .... ... ... (.:at#( n c l t frill grow11) . . . . t h o (:1dnlt) . . . . . . . . . . . Hiire (i tiiiri:itii R:) . . . . . . . 'I )"Is_. . . . . . . . . . . . . . ., . . . . : Iht (iiniiiiit < i n i ~ i c ~pig n 31il I1 ................... 1. . .......... 1.. 2T .2 -30.3 15.8 18.2 39.8 1 7 . 6 21 .!I 27.4-28. $5 31.4 1f i3 .0 22.9 "5.8 m.4 Pig. .................... Sheep ($1 170, wdult) . . . . . Shccp (M 135, (imos.). . . 46.2 Sht?qJ(M %!), 3 mos. j . .. 'I1I l l 1.................... Id. 1-23. i 14.tj l i . 2 2 . 6 iO.0 Thc average cross-sectional area of the lubnle in the rat tcnticlc R 11 is 0.0553 sq.mm. and in the human testicle X 10 is 0.0263-in rouiitl iiumhers, a difereiice of 50 per cent. r1.i he significance of tubule size may perliaps bc more easil~* gi*aspetlwlitlri expressed as in table 2, column 1, in terms of tlw nnml)cr of rncdors of tuhiile,s cqixivaleat t o 1 gram iii weiglit or 1 cc. i u volume. Kveri after allowance is made for tuiiica albugiiiea am1 metliastiinim, normal adult testicles vary in relative percent ages of tnhules and interstitial tissue. These variations in the species studied arc summarized in table 3. In each case 165 QUANTITATIVE STUDIES OF THE TESTICLE the percentage of interstitial tissue is therefore equal to 100 miniis the perccntage of tubules given in the table. Table 3 consequently indicates numerically the differences in pattern found in this series of normal adult testicles due t o varyiiig amounts of interstitial tissue. Total tubule lengths f o r the adult ariimals studied are summarized in round numbers in table 4. Incidental data exist from which total tubule length in the testicle of man and of the mouse may be calculated. Cunningham gives figures indicating a total tubule length in the human testicle of 800 to 1200 feet. Our calculation, involving a different method, gives 249.7 meters, or 819 feet. Guinea. pip I Dog. . . . . . . . 1 M ~ I I R .~ .. . . . I Hare. ...... , Rat . . . . . . . . Cat ........ Sheep . . . . . . . Bull. . . . . . . . ! Alan ....... ’ Pig ........ 8!). 8-97.0 92.2-94.2 88.9-90.3 89.0 88.5-89. f i 84.5-86.9 84.6 76.4-83.9 72.8 62.2-72.6 i ............. 2 Rat ................ 20 (hinea pig. . . . . . . . . , 40 Cat (not full grown) 25 Belginn hare . . . . . . . 70 Dog ............... 150 &Ian... . . . . . . . . . . . . I 260 Pig ................ 3 o o o ~ ~ - m Sheep .............. 4000 Rull . . . . . . . . . . . . . . . 5000 Moiise 1 ~ . . .. -. ... Huber and Curtis state that the mouse testicle contains sixteen tubules. One tubule was found to be 13 em. in length. These figures imply a total tubule length for the mouse testicle of about 2 meters. Our figure, iridependently calculated, is also about 2 meters. To this extent previous data secured by methods entirely different from ours confirm our comput at i on s. At first glance the disparity in total tubule length between the larger and smaller mammals seems fairly incredible, but a little arithmetic will reveal that actually the smaller animals have a greater length of tubules per unit of body weight 16li I<. I,’. BRRCOM A N D H. L. OSTERUD t l ~ do n the larger ones. F o r example, in round numbers, a molls(’ would h a r c iihoiit 1 meter of tubules per 10 grams of I)ody weight, while a bull would have approximately 1 meter of tnhnles per 100 grams of body weight. If the testicle made up tho same percentage of body weight in the bull as it does in the mouse, tho bull testicle u70dd have, instead of 5000 rncLtvix of tubules, upwards of‘ 300,000 meters. In this conion it is iiitevesting to refer oiice more to table 1 and note that tho mouse has a tuhule diameter of almost 0.2 mm., \vIlilc. the bull has an average tubule dianieter only 16 pcr cent greater (0.24 mm.). In other words, increased volume of germinn1 fyitholium in larger tc*sticAlcs comes largely or wholly from iiici-ease in tubiile lwgtli, not from increase iu tiilnde diameter. ( ‘pi-tail1immature animals are marked in tnhle 1 witli ast(’i0isks. Rat K 3 was thirty-nine (lays old arid weighed 59..? gixrns. His tcsticle \wiglit was approximately 25 pcr cent t h a t of a iiormal atlnlt, but the total tubulc leiigtli of his tcsticlc was iilwut 50 per cent that of the adult. ]<;it K 2 \$rils sixty-six (lays oh1 N I I ~weighed 150 grams. His testicolar weight anti t ul)iile length were almost those of thr. aclult, although oiily i n the carlimt stages of sexual miit nrit y. Rat R 1 was 190 clays old and weighed 304 grams, yet his 1chsticillar weight am1 total tu’lntle leiigth olily sIight1~-oxccwied tliosv of H 2, \\-1io w a s oiici-third his age a d 011c-11;iIf liis 1)od:- w-eight. Kclgiaii hart X 19 TWS less tl1a11 i i third ~ T O M - I ~ . His t(hbticular 1s-eight was ahout oiie-elerenth and his tuhule lc11gt11 two-fifths that of X 18, an iitlnlt of the> same spccics. JI 399 1i7:is ii lamb, pcrlinps three months old. Its testiciil a r weight was ahout one-ele\-mitIi that of the atfult, hnt its ir i l ) i i l ( l It~iigtlim o w t l i a i i oiic-fourth that of the atlillt. Ji 13i w w ;I laml) akout six months old. Its tes:tic.111;11* wt.ig-tit w i s ahout Iialf that of the adnlt, h t its tnbnle lellgtll ;it loiisf ( v l i i a l t o t1i:it (JI’ acliilt ,I1 I i O . QUANTITATIVE STUDIES OF THE TESTICLE 167 These comparisons of immature with mature testicles lead to the conclusioii that total tubule length is greater in proportion to testicular weight in the young than in the adult testicle and that adult tubule length is probably attained in the growing animal a considerable time before adult testicular weight and adult tubule diameter have been reached. The factors which determine testicular pattern are tubule diameter, relative amount of interstitial tissue, and amount of tunica albuginea and mediastinum. These factors are individually variable. Tlie combined effect of their variability upon testicular pattern may he expressed numerically as in table 2, column 11,in terms of the number of meters of tubules per gram of testicular weight. These data are obviously secured by dividing the total tubule length of given testicles in meters by their respective weights in grams. This column illustrates the following points : similarity in pattern in tlie adult testicles of certain species, differences in pattern in the adult testicles of other species, a r i d changes in pattern during growth in a given species. BCMNAlIY AND COKCLUSIONS 1. A quantitative method is described for determining the amounts of interstitial tissue and seminiferous tubules as well as the total length of these tubules. Testicles from animals of the following specics wei’cl studied : albino mouse, albino rat, Guinea pig, cat, Belgian hare, dog, man, pig, sheep, and bull. 2. The gross weights of these testicles ranged from 0.0556 gram (albino mouse) to 367 grams (boar). 3. Adult tubule diameter had a maximum variation of only 0.1834 mm. (man) to 0.2654 mm. (albino rat). 4. Total tubule length in the adult varied from 1.67 meters (albino mouse) to 6312 meters (hoar). 5. The small variation in tubule diameter in conjunctioii mitli tlie tremendous differences in total tubule length indicate that space f o r increased volume of germinal epithelium in the larger testicles is afforded largely and sometimes 1C58 Xi. %’. BASCOM Ah’D H. L. OSTERUD wliolly by iiicrease iii total tubule lengtli, not b y increase in t nhule diamet cr. ti. In spite of the great total tubule length encountered iii the larger species. the smaller animwls, such as the mouse and rat, actually have a greater length of seminiferous tnbides per unit of body weight. 7. The pattern of a given testicle depends upoii the relative arnooiits of tunica albuginea, mediastinurn, interstitial tissue, aiitl tubules, ant1 upoii tuhule diameter. The combination of these factors as they occur iri a given testicle may be iiumcrically expressed in terms of number of meters of tubules per gram of total testicular weight. This slim varies with thtl species studied as well RS with the state of development of the individual (table 2, column 11). 8. Total tubule length is greater in proportion to total testicular weight in the poung than in the adult. 9. Adult tubule length probably is attained in the growing aiiimal a considerable time bef ore adult testicular weight and adult tubule diameter have been reached. QUANTlTATITrE STUDIES OF THE TESTICLE 169 BIBLIOGKAYII Y BASCON,K. F. 1926 Qu:intitative studies of the testis. T. Some observations on tlir ervptorcliid testes of sherp and swine. Anat. Rec., vol. 30. RESSESEN,A. N., AND CABLSOX,H. A. 1923 Postnatal growth in weight of the various orguns in the guinea pig. Am. Jour. Anat., vol. 31. BOUIN AND ANCEI, 1903 Testicule des M:immifcres. Arch. de Zool. Exp. et Gm., T. 1. 1904 Ulande interstitielle du testicule. Jour. de Phys. et de Path. Gen., T. 6. BREMER,J. L. 1911 Moiphology of the tubules of the liunian testis and epididymis. Am. Jour. Amit., vol. 11. CURTIS, G . M. 1918 The morpl~ology of the mammalian seminiferous tubule. Am. Jour. Anat., vol. 21. HATAI, SHINKISHI1913 On the weights of the abdominal and thoracic viscera, the sex glands, duetless glands, a n d the eyeballs of the albino rat (ItIus norvegicus albiiius) according t o body weight. Am. Jour. Anat., vol. la. JACKSON, C. M. 1913 Postnatal growth m d variability of the body and the various organs in the albino rat. Am. Jour. Anat., vol. 15. LATIMER,H. B. 1920 The weights of the viscera of the common frog. Anat. Rrc., ~ o l .18. 1920 The weights of the viscera of the turtle. Anat. Roc., vol. 19. MASSAGLIA,A. C. 1920 The internal secretion of the testis. Endocrinologp, vol. 4. IIUBER, G. C., AND CURTIS, C . M. 1913 Thr morpl~ology of the seminiferous tubules of mammalia. Anat. Rev., vol. 7. MOORE, C. R. 1924 Properties of the gonads iLS rontrollers of somatic an d psychieal characteristics. VI. Testicular reactions in experimental eryptorchidism. Am. Jour. Anat., vol. 34. RASNUSSEN, A. T. 1917 Seasonal changes in the interstitial cells of the testis in the woodrhuck (Marmota monax). Am. Jour. Anat., vol. 22. 1918 C;yclic changes in the interstitial rells of the ovary and testis in the woodchuck (Marmota rnonax). Endocrinology, vol. 2. RIDDLE,OSCAR 1916 Size and length relations of the right an d left testicles of pigeons in health and disease. Anat. Rec., vol. 11. 1918 Further observations on the relative size and form of the right and left testes in pigeons in health an d disease as influenced by hybridity. Anat. Rec., vol. 14. ROBINSON, ARTHUR 1920 Cunningham’s manual of practical anatomy, 7th edition. Vol. 2. Thorax and abdomen. SIPERSTEIN,D. M. 1921 The effects of acute and chronic inanition upon the development and structure of the testis in the albino rat. Anat. Rec., vol. 20. WATSON,ALEXAKDER1919 A study of seasonal changes in avian testes. Jour. of Phys., vol. 53.