Observations on Tissue Grafts Established in Rabbit Ear Chambers

Abstract

Early experiments using in vivo microscopy on mammalian tissues were reviewed by Clark et al. (1). The introduction of the transparent rabbit ear chamber, first described by Sandison (2, 3) has allowed microscopic observations to be made of the structure and function of a thin layer of living tissue in the mammal for periods up to several years (4).A modification of the Sandison-Clark rabbit ear chamber which allowed the mica cover slip to be removed, exposing the surface of the stable vascular membrane and then replaced, was adapted by Williams (4) to study graft tissue fragments implanted on the membrane. He found that autografts of a wide variety of tissues in fragments less than 1 mm diameter became vascularized by the anastomosis of graft vessels to the chamber vessels immediately beneath, and slowly became incorporated into the membrane. These grafts retained their structure and visible function (5). On the other hand, allograft tissues, with the exceptions of choroid plexus, ciliary body, V2 carcinoma, and to some extent adrenal, did not survive (5).Recently Greenblatt and others (6) established renal allografts in the hamster cheek pouch chamber and described the glomerular blood flow occurring during their brief survival. However, only fetal graft tissues could be used successfully and the glomerular blood flow always followed a preferential path in a relatively direct stream from the afferent to the efferent arterioles. Subsequently he has described fetal and neonatal heart grafts functioning in these chambers (7).With the eventual aim of studying the process of allograft rejection in vivo, we implanted tissues into the rabbit ear chamber b y a method adapted by Cliff et al. (8). Tissues successfully grafted include liver, kidney, myometrium, and thyroid. Materials and MethodsAnimal.--Rabbits used as recipients were obtained from a closed colony of half-lop rabbits maintained at the Australian National University. They were hardy animals with durable half-lop ears 16 cm in length, very suitable for transparent chamber insertion. Donor rabbits were either of a similar strain, though unrelated, or of an albino strain. Animals were fed on * Present address:

Vascularization of Normal Human Thyroid Tissue Transplanted to Nude Mice

“…This has been ob served in previous studies on transplanted tissue but other mechanisms have also been observed such as formation of sprouts in the transplant [6,36] or fusion of sprouts from host and transplant [14,19,20]. These dif ferent mechanisms might be related to the size of the transplant.…”

A Study of Allograft Kidney Rejection Occurring Simultaneously in Whole Organ and Ear Chamber Grafts in the Rabbit

“…When pieces of kidney were allografted into the rabbit ear chamber, they reestablished their blood circulation in 2-4 days by anastomosis of their cut vessels to the adjacent vasculature of the ear chamber membrane (6). Autografts appeared to function indefinitely, since autologous renal tissue was observed in the rabbit ear chamber withe ut change for 6 mo after fixation, and functioning myometrial autografts were observed for periods of up to 1 yr (6). Allografted renal tissues in the rabbit ear chamber reject after periods of up to 3 mo (6).…”

“…Autografts appeared to function indefinitely, since autologous renal tissue was observed in the rabbit ear chamber withe ut change for 6 mo after fixation, and functioning myometrial autografts were observed for periods of up to 1 yr (6). Allografted renal tissues in the rabbit ear chamber reject after periods of up to 3 mo (6). A whole kidney allografted in similar rabbits is rejected in 7 days.…”

Role of Glomerular Basement Membrane Thixotropy and Influence of Glomerular Vascular Pressure in the Pathogenesis of Immune Complex-Induced Glomerulonephritis

“…Focal lesions are seen which may involve only a single vessel in a glomerulus, and the origin of such lesions is not understood. Hobbs and Cliff [25] reported that preferential blood flow patterns had been observed in glomeruli maintained in rabbit ear chambers. It is possible that focal lesions may represent the presence of greater amounts of complex deposited simply because of the greater volume of blood passing along the preferred pathway.…”