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Uterine Skin Grafts and Fertility Control in the Rat
FERTILITY AND STERILITY Copyright c 1976 The American Fertility Society
Vol. 27, No.8, August 1976 Printed in U.SA.
UTERINE SKIN GRAFTS AND FERTILITY CONTROL IN THE RAT WOLFE Z. POLISHUK, M.D.,*
AND
HAIM YAFFE, M.D.
Department of Obstetrics and Gynecology, Hadassah University Hospital, Jerusalem, Israel
Autologous intrauterine skin grafting was studied as a method of fertility contol in the rat. Skin taken from the ear was grafted onto the right horn in 52 rats. All skin grafts "took" and developed into one of three forms: (1) replacement ofendometrium over a wide area, (2) polypoid formations, or (3) skin bridges. Curettage before the skin grafting did not affect the ,.,.take" or subsequent course of the graft. After mating, no pregnancy occurred in skingrafted horns, whereas control horns behaved like those in control rats. Results obtained in rat uteri indicate another approach to the treatment of uterine bleeding and possibly to contraception.
Laparotomy was performed under ether anesthesia. Uterine horns and ovaries were inspected to exclude gross pathology. A small (1 to 2 mm) incision was made in the lower part of each right hom. Through this incision, curettage was performed in 26 rats, using an especially constructed umbrella-shaped curette. One ear of each of the 52 rats was carefully shaved and a strip (4 x 10 mm) of full-thickness skin was dissected out and placed in the uterus, through the small incision previously made. There was no need to suture this incision. Twenty-one days after implantation, MATERIALS AND METHODS 40 rats that had received the skin transSixty-two mature virgin rats of the plant and 10 control rats were allowed Hebrew University Sabra strain, each to mate for 7 days. After another 7 days, weighing 170 to 190 gm, were used in the female rats were killed. The 12 rethis study. They were housed five to a maining rats, in groups of three, were cage and maintained under uniform conmated 3, 6, 9, and 12 months after the ditions. Of these rats, 10 served as conskin transplantation. They were killed trols and skin was transplanted into the 1 week later. uteri of the other 52. Uteri were removed and fixed in 10% formaldehyde. Transverse sections of the Accepted March 12, 1976. *Established Investigator, Chief Scientist's Of- fixed uteri were made at various levels, fice, Department of Health, Israel. from the vagina to the upper border of Endometrial regeneration following its denudation by curettage or menstruation is usually not accompanied by scar formation. Successful interference with this regenerative process could offer several clinical advantages. Previous attempts in laboratory animals1• 2 and humans 3 have brought partial success in this area. This report concerns the ability of autologous skin grafts to replace the endometrium, with and without previous curettage, and the possible role of such a graft in fertility control.
I
•
975
POLISHUK AND YAFFE
976
August 1976
TABLE 1. Pregnancy in Rats with Skin Graft in Right Horn and in Control Rats Site of pregnancy Treatment
Skin graft Controls
No. of rats
52
10
No. pregnant
42 (80%) 7 (70%)
Right hom
Left horn
0
42 7
7
FIGs. 1 AND 2. Autologous skin graft "took" over a wide area of the uterine wall, followed by epidermization of opposite and adjacent walls.
...
Vol. 27, No.8
UTERINE SKIN GRAFTS AND FERTILITY CONTROL IN THE RAT
the uterine hom. Tissue blocks were embedded in paraffin, sectioned, and stained with Mayer's hematoxylin and eosin. Four to six sections from different levels were examined under a light microscope.
977
RESULTS
Of the 52 rats bearing the skin transplant, 42 became pregnant in the left hom only. This rate was similar to that of the control group (Table 1).
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FIGs. 3 AND 4. Autologous skin graft "took" over a limited area: of the uterus, to form a polypoid structure protruding to a different extent into the lumen. The surrounding endometrium was invaded by squamous cells, which may be seen exfoliating into the uterine lumen.
POLISHUK AND YAFFE
978
Examination of all sections of the right uterine horns in which autologous skin grafts were implanted showed that the grafts took well. The degree of extension of the graft, replacing the normal endometrium, was not related to the time elapsed from the operation. Replacement of the normal endo-
August 1976
metrium by the skin graft was always segmental and corresponded to the area in which the graft was placed. There was no difference in behavior of the graft in curetted and noncuretted horns. The ultimate course of skin growth in the grafted horns took one of three forms: (1) replacement of endometrium over a
,,'',-,,:<,
••• 5 AND 6. The autologous skin grafted onto the uterine lumen forms bridges to opposite uterine walls. FiGs.
Vol. 27, No.8
r 1 I
l..l,
UTERINE SKIN GRAFI'S AND FERTILITY CONTROL IN THE RAT
wide area, with epidermization of large sections of endometrium (Figs. 1 and 2); (2) polypoid growths of the grafted skin, partially filling the uterine cavity and inducing atrophy of adjacent endometrium (Figs. 3 and 4); or (3) grafted skin bridge formations joining opposite uterine walls (Figs. 5 and 6). One or more of these forms of "take" were found in every uterus in which the skin transplant was performed. Sections from the left horn (control horn) of each of the 42 pregnant rats and 7 of 10 control rats showed normal decidual changes. There was no evidence of squamous metaplasia or squamous cell invasion in this horn. DISCUSSION
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I I
We studied various methods of inducing scar tissue formation to replace endometrium. These studies had as an object the transformation of a functional, menstruating, decidua-forming lining into an inert cover of the uterine wall. This alteration could serve to reduce or eliminate menstrual loss as well as induce infertility. 4 • 5 Such attempts have met with partial success. The intrauterine skin graft was studied with these objectives in mind. Curettage was not essential for the success of the graft, and the same results were observed in curetted and noncuretted horns. The growth of the skin graft was always limited to the area of contact at grafting and to a limited surrounding area. We could not confirm the observations of Zipper et al., 6 who saw proliferation of squamous cells over the entire horn and extending into the control horn through the external os. The limited extent of squamous cell proliferation was also observed in rats in which the grafting had taken place 12 months before sacrifice. Blood vessels were seen in the grafts, which would account for the prolonged survival of the graft.
979
No pregnancy occurred in the skingrafted horns. The mechanism whereby the graft acts as a contraceptive is not well understood. The grafts did not completely replace the endometrium, so that implantation should not have been inhibited at a site of normal endometrium in the grafted horn. It is possible, however, that the graft acted as an intrauterine device or induced increased uterine motility, with extrusions of zygotes. Another possibility is that the exfoliated squamous cells interfered with implantation of the egg (see Figs. 1 to 6). The results obtained in rat uteri indicate another approach to the treatment of uterine bleeding and another possible approach to contraception. At diagnostic curettage, in cases of menometrorrhagia when malignancy has been excluded, a full-thickness skin graft taken from the vulva or lower vagina could be placed in the uterus so as to form an intrauterine skin graft. This would be expected to reduce the bleeding area and might also serve as an intrauterine device. The same procedure could be attempted at curettage for abortion, when the patient is not interested in additional pregnancies. REFERENCES 1. Polishuk WZ, Schenker JG: Induction of intra-
2.
3. 4.
5.
6.
uterine adhesions in the rabbit with autogenous fibroblast implants. Am J Obstet Gynecol 115:789, 1973 Polishuk WZ, Yaffee H, Laufer A: Induction of intra-uterine adhesions in the rat uterus. Harefuah 86:144, 1974 Polishuk WZ: Endometrial regeneration and adhesion formation. S Afr Med J 49:440, 1975 Schenker JG, Shoshan SH, Polishuk WZ: Delayed regeneration of endometrium induced by enriched collagen solutions. Isr J Med Sci 9:195, 1973 Schenker JG, Polishuk WZ: Regeneration of rabbit endometrium following intrauterine instillation of chemical agents. Gynecol Invest 4:1, 1973 Zipper J, Fernando G, Saez G, Tchernitchin A: Intrauterine grafting in rats of autologous and homologous adult rat skin. Am J Obstet Gynecol 94:1056, 1966
Vol. 27, No.8, August 1976 Printed in U.SA.
UTERINE SKIN GRAFTS AND FERTILITY CONTROL IN THE RAT WOLFE Z. POLISHUK, M.D.,*
AND
HAIM YAFFE, M.D.
Department of Obstetrics and Gynecology, Hadassah University Hospital, Jerusalem, Israel
Autologous intrauterine skin grafting was studied as a method of fertility contol in the rat. Skin taken from the ear was grafted onto the right horn in 52 rats. All skin grafts "took" and developed into one of three forms: (1) replacement ofendometrium over a wide area, (2) polypoid formations, or (3) skin bridges. Curettage before the skin grafting did not affect the ,.,.take" or subsequent course of the graft. After mating, no pregnancy occurred in skingrafted horns, whereas control horns behaved like those in control rats. Results obtained in rat uteri indicate another approach to the treatment of uterine bleeding and possibly to contraception.
Laparotomy was performed under ether anesthesia. Uterine horns and ovaries were inspected to exclude gross pathology. A small (1 to 2 mm) incision was made in the lower part of each right hom. Through this incision, curettage was performed in 26 rats, using an especially constructed umbrella-shaped curette. One ear of each of the 52 rats was carefully shaved and a strip (4 x 10 mm) of full-thickness skin was dissected out and placed in the uterus, through the small incision previously made. There was no need to suture this incision. Twenty-one days after implantation, MATERIALS AND METHODS 40 rats that had received the skin transSixty-two mature virgin rats of the plant and 10 control rats were allowed Hebrew University Sabra strain, each to mate for 7 days. After another 7 days, weighing 170 to 190 gm, were used in the female rats were killed. The 12 rethis study. They were housed five to a maining rats, in groups of three, were cage and maintained under uniform conmated 3, 6, 9, and 12 months after the ditions. Of these rats, 10 served as conskin transplantation. They were killed trols and skin was transplanted into the 1 week later. uteri of the other 52. Uteri were removed and fixed in 10% formaldehyde. Transverse sections of the Accepted March 12, 1976. *Established Investigator, Chief Scientist's Of- fixed uteri were made at various levels, fice, Department of Health, Israel. from the vagina to the upper border of Endometrial regeneration following its denudation by curettage or menstruation is usually not accompanied by scar formation. Successful interference with this regenerative process could offer several clinical advantages. Previous attempts in laboratory animals1• 2 and humans 3 have brought partial success in this area. This report concerns the ability of autologous skin grafts to replace the endometrium, with and without previous curettage, and the possible role of such a graft in fertility control.
I
•
975
POLISHUK AND YAFFE
976
August 1976
TABLE 1. Pregnancy in Rats with Skin Graft in Right Horn and in Control Rats Site of pregnancy Treatment
Skin graft Controls
No. of rats
52
10
No. pregnant
42 (80%) 7 (70%)
Right hom
Left horn
0
42 7
7
FIGs. 1 AND 2. Autologous skin graft "took" over a wide area of the uterine wall, followed by epidermization of opposite and adjacent walls.
...
Vol. 27, No.8
UTERINE SKIN GRAFTS AND FERTILITY CONTROL IN THE RAT
the uterine hom. Tissue blocks were embedded in paraffin, sectioned, and stained with Mayer's hematoxylin and eosin. Four to six sections from different levels were examined under a light microscope.
977
RESULTS
Of the 52 rats bearing the skin transplant, 42 became pregnant in the left hom only. This rate was similar to that of the control group (Table 1).
r
I.
I
r ~
I
I
'I'
FIGs. 3 AND 4. Autologous skin graft "took" over a limited area: of the uterus, to form a polypoid structure protruding to a different extent into the lumen. The surrounding endometrium was invaded by squamous cells, which may be seen exfoliating into the uterine lumen.
POLISHUK AND YAFFE
978
Examination of all sections of the right uterine horns in which autologous skin grafts were implanted showed that the grafts took well. The degree of extension of the graft, replacing the normal endometrium, was not related to the time elapsed from the operation. Replacement of the normal endo-
August 1976
metrium by the skin graft was always segmental and corresponded to the area in which the graft was placed. There was no difference in behavior of the graft in curetted and noncuretted horns. The ultimate course of skin growth in the grafted horns took one of three forms: (1) replacement of endometrium over a
,,'',-,,:<,
••• 5 AND 6. The autologous skin grafted onto the uterine lumen forms bridges to opposite uterine walls. FiGs.
Vol. 27, No.8
r 1 I
l..l,
UTERINE SKIN GRAFI'S AND FERTILITY CONTROL IN THE RAT
wide area, with epidermization of large sections of endometrium (Figs. 1 and 2); (2) polypoid growths of the grafted skin, partially filling the uterine cavity and inducing atrophy of adjacent endometrium (Figs. 3 and 4); or (3) grafted skin bridge formations joining opposite uterine walls (Figs. 5 and 6). One or more of these forms of "take" were found in every uterus in which the skin transplant was performed. Sections from the left horn (control horn) of each of the 42 pregnant rats and 7 of 10 control rats showed normal decidual changes. There was no evidence of squamous metaplasia or squamous cell invasion in this horn. DISCUSSION
r
I I
We studied various methods of inducing scar tissue formation to replace endometrium. These studies had as an object the transformation of a functional, menstruating, decidua-forming lining into an inert cover of the uterine wall. This alteration could serve to reduce or eliminate menstrual loss as well as induce infertility. 4 • 5 Such attempts have met with partial success. The intrauterine skin graft was studied with these objectives in mind. Curettage was not essential for the success of the graft, and the same results were observed in curetted and noncuretted horns. The growth of the skin graft was always limited to the area of contact at grafting and to a limited surrounding area. We could not confirm the observations of Zipper et al., 6 who saw proliferation of squamous cells over the entire horn and extending into the control horn through the external os. The limited extent of squamous cell proliferation was also observed in rats in which the grafting had taken place 12 months before sacrifice. Blood vessels were seen in the grafts, which would account for the prolonged survival of the graft.
979
No pregnancy occurred in the skingrafted horns. The mechanism whereby the graft acts as a contraceptive is not well understood. The grafts did not completely replace the endometrium, so that implantation should not have been inhibited at a site of normal endometrium in the grafted horn. It is possible, however, that the graft acted as an intrauterine device or induced increased uterine motility, with extrusions of zygotes. Another possibility is that the exfoliated squamous cells interfered with implantation of the egg (see Figs. 1 to 6). The results obtained in rat uteri indicate another approach to the treatment of uterine bleeding and another possible approach to contraception. At diagnostic curettage, in cases of menometrorrhagia when malignancy has been excluded, a full-thickness skin graft taken from the vulva or lower vagina could be placed in the uterus so as to form an intrauterine skin graft. This would be expected to reduce the bleeding area and might also serve as an intrauterine device. The same procedure could be attempted at curettage for abortion, when the patient is not interested in additional pregnancies. REFERENCES 1. Polishuk WZ, Schenker JG: Induction of intra-
2.
3. 4.
5.
6.
uterine adhesions in the rabbit with autogenous fibroblast implants. Am J Obstet Gynecol 115:789, 1973 Polishuk WZ, Yaffee H, Laufer A: Induction of intra-uterine adhesions in the rat uterus. Harefuah 86:144, 1974 Polishuk WZ: Endometrial regeneration and adhesion formation. S Afr Med J 49:440, 1975 Schenker JG, Shoshan SH, Polishuk WZ: Delayed regeneration of endometrium induced by enriched collagen solutions. Isr J Med Sci 9:195, 1973 Schenker JG, Polishuk WZ: Regeneration of rabbit endometrium following intrauterine instillation of chemical agents. Gynecol Invest 4:1, 1973 Zipper J, Fernando G, Saez G, Tchernitchin A: Intrauterine grafting in rats of autologous and homologous adult rat skin. Am J Obstet Gynecol 94:1056, 1966