활액막 재생에 관한 실험적 연구

Abstract

[한글]

Experimental Studies on the Regeneration of Synovial Membrane in Rabbits

Yun Ku Choi, H.D.

Department of Medical Science Graduate School, Yonsei University

(Directed by Prof. In Hee Chung)

Over the past century a great deal of interest has been rekindled in the

regeneration of synovial membrane after synovectomy.

The regeneration of synovial membrane has been studied repeatedly by numerous

investigators in animals and membrane has been found to return to its previous form

in thirty to sixty days Sumita(1912) performed synovectomies on one knee in each of

two dogs and studied joints after synovectomies arid Sumita's two dogs are the only

first reported cartes in the literature on the conditions after synovectomies.

The mechanism of synovial regeneration following synovectomy was widely debated

during the early part of this century. It is possible that a new membrane is either

regenerated from remnants left behind at the operation or reformed by a metaplasia

of cells in the underlying tissue. Previous to the report of Key(1925), it was a

accepted general belief that regeneration of synovial membrane took place largely

as the result of extension over the denuded surface from remaining synovial pouch

tags rather than by specialization of new fibrous tissue cells.

Segale (1913) also thought regeneration occured from residual synovial cells.

However. Key(1925) and Wolcott (1927), working independently, excised varying

amounts of synovium from animal joints and studied regeneration of the membrane.

They concluded that the tissue was reconstituted in about sixty days by metaplasia

of underlying connective tissue elements in the area, rather than by ingrowth from

the remaining synovium. On the other hands, Mitchell and Cruess(1967) established

the mechanism of synovial regeneration using an autoradiographic study with

tritiated thymidine.

Mitchell and Blackwell (1969) studied ultrastructure of regenerating synovial

membrane in rabbits after subtotal synovectomy and revealed that macrophages

transformed into type A cells, fibroblasts transformed into type B cells and a new

membrane was established by thirty-five days and continued to mature until 100 days

at which time regenerated synovium could not be distinguished from the normal ender

the electron microscope.

In clinical practices, Schuller (1887) was the first who did synovectomies for

rheumatoid arthritis and Mignon (1900) reported a case of chronic traumatic

arthritis successfully treated by synovectomy.

Recently, Peterson (1968), Geens(1969), Dick et at. (1970), Goodie(1972),Patzakis

et al. (1979) and Graham et at. (1973) Performed synovectomies (or rheumatoid

arthritis independently and had demonstrated that after synovectomy the regenerated

synovium showed histological appearances suggesting a recurrence of the rheumatoid

process and an increased amount of lysosomal enzymes, as in the original diseased

membrane.

Untill the present time, histochemical studies of normal synovium in hymen and

animals have been reported by numerous investigators, but no histochemical changes

of regenerating synovial membrane in experimental animals have yet been reported in

the literature. The purpose of the present investigations is mainly to observe

histochemical changes as well as macroscopic, histological and electron microscopic

findings of regenerating synovial membrane after synovectomy.

Healthy mature rabbits weighing about 2 Kg were used as experimental animals.

Under seconal intravenous anesthesia subtotal synovectomy was carried 7ut on one

knee of the rabbit. The joint was exposed through a medial parapatellar incision

and the fat pad, suprapatellar pouch, both menisci and all available synovium were

removed. On the opposite knee of each rabbit, partial synovectomy was done. In the

cartes of partial synovectomy only the medial half of the synovium was removed and

the process of synovial membrane regeneration between subtotal and partial

synovectomized groups was compared and 5 rabbits served as normal controls. The

rabbits were sacrified by air embolism in groups of 5 at 2, 4, 8, 15, 35 and 70

days after synovectomy.

Samples of regenerating synevium were removed from the areas previously occupied

by normal synovium. For histological examinations, aerial sections were prepared

and stained with hematoxylin-eosin. To demonstrate the activity of adenosine

triphosphatase, the method presented by Wachstein and Meisel (1957) was uses. The

sections were stained by the periodic acid-Schiff method of Hotchkiss(1948) and the

malt diastase digestion method for synovial mucin. Methyl green-pyronin staining

with Lillie's method (1954) was usee for ribonucleic acid. For metachromasia, the

sections were stained with toluidine blue. Electron microscopic studies of synovium

were carried out in normal controls and 35 days after synovectomy. To observe the

influences of synovectomy on articular cartilage, articular cartilages of medial

condyle of femur were sectioned and after decalcification, paraffin blocks made,

stained with hematoxylin-eosin for histological examinations and stained with

toluidine blue for metachromasia.

The results concluded from the present studies are ;

1. Underlying connective cells began to proliferate from 2 days after

synovectomy. Four days after synovectomy, the fibroblasts had greatly increased in

number and had wondered out into the fibrin layer. Eight nays after synovectomy,

the denuded surface was begun to cover by 1-2 layers of fibroblasts incompletely

but fibroblasts were still more numerous and 15 days after synovectomy, the number

of cells had decreased great1y and synovial membrane was reconstituted to its

normal control form in 35 days after synovectomy macroscopically, histologically

and electron microscopically.

2. In normal controls, strong PAS reactions were present in cytoplasms of

synovial cells and in some places the cells appeared to be coverer by a thin band

of PAS positive materials. Two days and 4 days after synovectomy, PAS positive

materials in cytoplasms of proliferating fibroblasts were greatly decreased and 8

days after synovectomy. proliferating cells showed moderate PAS reactions. From 15

days after synovectomy, cells had strong PAS positive material in their

cytoplasms as in that of normal controls.

3. Synovial cells of normal controls showed a strong ATP-ase activity. ATP-ase

activity was markedly diminished in 2 days after synvectomy. From 4 days after

synovectomy, ATP-ase activity began to rice. From 35 days after synovectomy,

surface lining cells showed a strong ATP-ase activity and could not be

distinguished from that of normal controls.

4. With methyl green-pyronin staining for RNA, almost all synovial cells of

normal controls had few pyroninophilic granules in their cytoplasms.

Two days after synovectomy, proliferating cells showed moderate staining

reactions. Four days and 8 days after synovectomy, cells showed a definite increase

in number of pyroninop-hilic granules in their cytoplasms. From 15 dabs after

synovectomy, pyreninophilic granules of cells began to decrease and 38 days after

synovectomy, cells showed only a faint staining reactions as in that of normal

controls.

5. Toluidine blue gave only faint metachromasia to the very rarely seen masts

cells at 35 days after synovectomy and fibroblasts at 8 dabs and 15 days after

synovectomy.

6. There were no alterations in the appearances of chondrocytes throughout the

experiments, but metachromasia of articular cartilages decreased markedly from 2

days to 15 days after synovectomy. From 35 days after synovectomy, metachromasia

returned to its normal staining character.

7. In all specimens, no differences could be found between subtotal and partial

synovectomized groups in the process of synovial membrane regeneration.

It is suggested that in the Process of synovial membrane regeneration after

synovectomy, a part of the functional aspects paralell the morphological changes.

[영문]

Over the past century a great deal of interest has been rekindled in the regeneration of synovial membrane after synovectomy.

The regeneration of synovial membrane has been studied repeatedly by numerous investigators in animals and membrane has been found to return to its previous form in thirty to sixty days Sumita(1912) performed synovectomies on one knee in each of

two dogs and studied joints after synovectomies arid Sumita's two dogs are the only first reported cartes in the literature on the conditions after synovectomies.

The mechanism of synovial regeneration following synovectomy was widely debated during the early part of this century. It is possible that a new membrane is either regenerated from remnants left behind at the operation or reformed by a metaplasia of cells in the underlying tissue. Previous to the report of Key(1925), it was a accepted general belief that regeneration of synovial membrane took place largely as the result of extension over the denuded surface from remaining synovial pouch tags rather than by specialization of new fibrous tissue cells.

Segale (1913) also thought regeneration occured from residual synovial cells. However. Key(1925) and Wolcott (1927), working independently, excised varying amounts of synovium from animal joints and studied regeneration of the membrane. They concluded that the tissue was reconstituted in about sixty days by metaplasia of underlying connective tissue elements in the area, rather than by ingrowth from the remaining synovium. On the other hands, Mitchell and Cruess(1967) established the mechanism of synovial regeneration using an autoradiographic study with

tritiated thymidine.

Mitchell and Blackwell (1969) studied ultrastructure of regenerating synovial membrane in rabbits after subtotal synovectomy and revealed that macrophages transformed into type A cells, fibroblasts transformed into type B cells and a new

membrane was established by thirty-five days and continued to mature until 100 days at which time regenerated synovium could not be distinguished from the normal ender the electron microscope.

In clinical practices, Schuller (1887) was the first who did synovectomies for rheumatoid arthritis and Mignon (1900) reported a case of chronic traumatic arthritis successfully treated by synovectomy.

Recently, Peterson (1968), Geens(1969), Dick et at. (1970), Goodie(1972),Patzakis et al. (1979) and Graham et at. (1973) Performed synovectomies (or rheumatoid arthritis independently and had demonstrated that after synovectomy the regenerated

synovium showed histological appearances suggesting a recurrence of the rheumatoid process and an increased amount of lysosomal enzymes, as in the original diseased membrane.

Untill the present time, histochemical studies of normal synovium in hymen and animals have been reported by numerous investigators, but no histochemical changes of regenerating synovial membrane in experimental animals have yet been reported in the literature. The purpose of the present investigations is mainly to observe histochemical changes as well as macroscopic, histological and electron microscopic findings of regenerating synovial membrane after synovectomy.

Healthy mature rabbits weighing about 2 Kg were used as experimental animals.

Under seconal intravenous anesthesia subtotal synovectomy was carried 7ut on one knee of the rabbit. The joint was exposed through a medial parapatellar incision and the fat pad, suprapatellar pouch, both menisci and all available synovium were

removed. On the opposite knee of each rabbit, partial synovectomy was done. In the cartes of partial synovectomy only the medial half of the synovium was removed and the process of synovial membrane regeneration between subtotal and partial synovectomized groups was compared and 5 rabbits served as normal controls. The

rabbits were sacrified by air embolism in groups of 5 at 2, 4, 8, 15, 35 and 70 days after synovectomy.

Samples of regenerating synevium were removed from the areas previously occupied by normal synovium. For histological examinations, aerial sections were prepared and stained with hematoxylin-eosin. To demonstrate the activity of adenosine

triphosphatase, the method presented by Wachstein and Meisel (1957) was uses. The sections were stained by the periodic acid-Schiff method of Hotchkiss(1948) and the malt diastase digestion method for synovial mucin. Methyl green-pyronin staining

with Lillie's method (1954) was usee for ribonucleic acid. For metachromasia, the sections were stained with toluidine blue. Electron microscopic studies of synovium were carried out in normal controls and 35 days after synovectomy. To observe the

influences of synovectomy on articular cartilage, articular cartilages of medial condyle of femur were sectioned and after decalcification, paraffin blocks made, stained with hematoxylin-eosin for histological examinations and stained with toluidine blue for metachromasia.

The results concluded from the present studies are ;

1. Underlying connective cells began to proliferate from 2 days after

synovectomy. Four days after synovectomy, the fibroblasts had greatly increased in

number and had wondered out into the fibrin layer. Eight nays after synovectomy,

the denuded surface was begun to cover by 1-2 layers of fibroblasts incompletely

but fibroblasts were still more numerous and 15 days after synovectomy, the number

of cells had decreased great1y and synovial membrane was reconstituted to its

normal control form in 35 days after synovectomy macroscopically, histologically

and electron microscopically.

2. In normal controls, strong PAS reactions were present in cytoplasms of

synovial cells and in some places the cells appeared to be coverer by a thin band

of PAS positive materials. Two days and 4 days after synovectomy, PAS positive

materials in cytoplasms of proliferating fibroblasts were greatly decreased and 8

days after synovectomy. proliferating cells showed moderate PAS reactions. From 15

days after synovectomy, cells had strong PAS positive material in their

cytoplasms as in that of normal controls.

3. Synovial cells of normal controls showed a strong ATP-ase activity. ATP-ase

activity was markedly diminished in 2 days after synvectomy. From 4 days after

synovectomy, ATP-ase activity began to rice. From 35 days after synovectomy,

surface lining cells showed a strong ATP-ase activity and could not be

distinguished from that of normal controls.

4. With methyl green-pyronin staining for RNA, almost all synovial cells of

normal controls had few pyroninophilic granules in their cytoplasms.

Two days after synovectomy, proliferating cells showed moderate staining

reactions. Four days and 8 days after synovectomy, cells showed a definite increase

in number of pyroninop-hilic granules in their cytoplasms. From 15 dabs after

synovectomy, pyreninophilic granules of cells began to decrease and 38 days after

synovectomy, cells showed only a faint staining reactions as in that of normal

controls.

5. Toluidine blue gave only faint metachromasia to the very rarely seen masts

cells at 35 days after synovectomy and fibroblasts at 8 dabs and 15 days after

synovectomy.

6. There were no alterations in the appearances of chondrocytes throughout the

experiments, but metachromasia of articular cartilages decreased markedly from 2

days to 15 days after synovectomy. From 35 days after synovectomy, metachromasia

returned to its normal staining character.

7. In all specimens, no differences could be found between subtotal and partial

synovectomized groups in the process of synovial membrane regeneration.

It is suggested that in the Process of synovial membrane regeneration after

synovectomy, a part of the functional aspects paralell the morphological changes.