동종태반 및 Adjuvant 반복주사로 인한 백서신장의 조직화학적 및 전자현미경적 관찰

Abstract

[한글]

[영문]Toxemia of pregnancy, a disorder of the human characterized by hypertension, proteinuria, edema and in certain cases, convulsion an coma, is a peculiar symptom complex with unknown etiology and mechanism.

McKay and his associates (1953), reported that intravascular fibrin deposition in arterioles and capillaries, throughout the body is responsible for the necrosis and hemorrhage seen in eclampsia and speculated that the mechanism behind the fibrin

deposition is similar to that in the generalized Schwartzman reaction.

Certainly, lesions of the brain, pituitary, liver and kindney may occur in toxemia of pregnancy, but it is generally accepted that the lesions of the kidney constitute the specific pathologic disturbance and many excellent studies have been carried out dealing with the renal lesions in the toxemia of pregnancy (Bell, 1932; Baird & Dunn, 1933; Sheehan, 1950; Govan, 1954; Dieckmann, 1957; and Spargo, et al. 1959).

In 1947, a condition closely simulating toxemia of pregnancy with albuminuria, hypertension and edema was produced in rats by sensitizing them against placenta protein before they became pregnant and the histopathologic changes of the kidney corresponded closely to the early lesions in the human toxemia of pregnancy (Lin, 1947).

With the improvement of biopsy technique, fresh renal tissue became available and renal lesions at various stages of toxemia were observed with light and electron microscope by many authors. Certain lesions were felt to be diagnostic (Dieckman, et al., 1957; Hopper, et al., 1961; Altchek, 1961; Mautner, 1962; Pirani, et al., 1963; Altchek, 1964; Altchek, et al., 1968).

In 1967, Irino and his associates induced similar renal lesions to those of human toxemia by repeated intraperitoneal injections of homologous placenta in rats and concluded that the lesions were closely resembled the vascular lesions which are caused by autoimmune reactions.

The present study is an attempt to establish the pathologic changes induced by sensitizing the rat against homologous placenta and to compare them with the lesions of kidney in human toxemia.

Materials and Methods

Healthy male and female rats weighing around 200gm were used and a total of 50 rats were subjected to the experiment . The animals were divided into 4 major groups and treated as follows:

Group Ⅰ : Normal control (6 rats)

Group Ⅱ : Adjuvant only (6 rats)

Group Ⅲ : Placental emulsion with adjuvant (32 rats)

A. 14th day whole placenta

B. 18th day whole placenta

C. Labyrinth of 20th day placenta

D. Junctional zone of 20th day placenta

Group Ⅳ : Homologous kidney emulsion with adjuvant (6 rats)

The antigens were prepared as follows: Placentae were removed on the 14th, 18th, and 20th day of pregnancy. After washing them with sterile isotonic saline solution several times, a 30% saline suspension of placena was made with the tissue homogenizer, and added to the same amount of Freund's complete adjuvant (Difco

laboratories, U.S.A.). Antigens were injected at weekly nitervals for eight weeks intra-peritoneally and each dosage was 0.5cc per animal. During this period, body weight and urine protein were checked weekly. All animals were sacrificed and necropsied about 4 to 6 weeks after the last injection of antigen. After gross

examination, one part of the kidney was fixed in 10% formalin and cut in 6 micron thickness after paraffin embedding. It was then stained with routine hematoxyline-eosin and Periodic acid Schiff (PAS). For electron microscopic examination, the kidney was subdivided into 3 parts, outer cortex, inner cortex and medulla. Tissues were fixed in 1% osmium tetraoxide in veronal buffer at pH of 7.4, for 2 hours each, and were dehydrated at 4'C in a graded series of ethanol solutions and embedded in Epon 812 or 815. Ultrathin sections were made with glass knife in 400 to 500 A and were stained with uranyl acetate and with lead hydroxide.

sections were examined in Hitachi HU-11E electron microscope.

Result and Summary

The changes of body weight of the rats in Group Ⅰ, Ⅱ and Ⅲ-B were not significant. But in Group Ⅲ-A, Ⅲ-C, and Ⅲ-D, the body weight was markdly increased during 4th to 7th week, and the increment corresponded to 7 to 15% of the body weight at initial point. In group Ⅳ, the body weight decreased 5% during the

first week, but gradually increased eventhough they failed to reach normal full recovery.

Proteinuria was seen in all animals in Group Ⅲ but in only one in Group Ⅳ. Proteinuria was noted at the 4th week and reached a peak level at the 6th week.

At necropsy, the kidney of the rats in group Ⅰ, Ⅱ and Ⅳ disclosed no specific gross changes. In group Ⅲ, increased perirenal fat tissue, mild edematous swelling of the kidney, adherent renal capsule and pale cortex on cut surfaces were noted

grossly.

On light microscopic examination definite lesions were identified only in the kidneys of the rats in Group Ⅲ. At the glomeruli, the endothelial and epithelial cells were enlarged with narrowed capillary lumen. Thickening of the basement membranes and ischemia were the constant findings and all glomeruli were affected equally. The enlargement of endothelial cells was more prominent in the kidneys of rats in Group Ⅲ-A, and Ⅲ-D, where as the epithelial changes had no group

preponderance.

Deposition of PAS-positive material was marked in Group Ⅲ-C and mild in remaining subgroups. Ischemic chagnes were more severe in glomeruli in Group Ⅲ-D.

At the tubules, mild hyaline changes were noted in proximal and distal tubules with occasional degeneration and destruction of epithelial cells of proximal convoluted tubules, and these lesions were rather severe in Group Ⅲ-C and Ⅲ-D.

Thickening of arteriolar walls were also more prominent in Group Ⅲ-C and Ⅲ-D.

In Group Ⅳ, only mild changes were noted, such as enlargement of endothelium, proliferation of epithelium and thichkening of arterioles.

On electron microscope, the findings of kidneys in control group were not differ from that of reported normal rat kidney. In Group Ⅱ, no ultrastructural alternations were identified, comparing with normal kidney. In Group Ⅲ-A, basement

membrane was focally thickened and endothelial cells were enlarged with swollen nuclei and narrowed capillary lumen. The nuclei of the epithelial cells were also enlarge and had irregular chromatin patterns which were clumped at the periphery.

The nuclear membranes became indistinct and in the cytoplasm, vacuoles and vesicle appeared in varying sizes and granulated endoplasmic reticulum almost completely disappeared. The Golgi apparatus were swollen and the foot processes were fused to

each other with infiltration of membranous materials in Bowman's spaces.

Mesangial cells disclosed similar alterations in the endothelium, such as mild enlargement at the capillary axis and decreased density of the cytoplasm.

In Group Ⅲ-B and Ⅲ-C, all alterations were more marked, but changes of the nuclear membrane was more mild and occasional osmophilic bodies were found in Group Ⅲ-C.

In Group Ⅲ-D, the enlargement of the endothelium is marked and the capillary lumen was almost completely obstructed. The basement membranes were focally thickened and similar to that of Group Ⅲ-B.

In summary, the renal lesions which were induced by repeated injection of homologous placenta in rats were closely related to that of human toxemia of pregnancy.