Myocardium and cortex cerebri xenografts transplanted into the anterior chamber of the eye of athymic rats: a morphologic and electrophysiologic profile.

Heart atria and cortex cerebri from fetal rabbits (E14 and E18, respectively) were grafted into the anterior eye chamber of anesthetized athymic nude rats and allowed to mature for 2-11 weeks. All grafts received a rich vascular supply from the host iris. Atrial transplants survived well but showed no significant growth while cortex grafts increased in size an average of 320%. Spontaneous action potentials were recorded from cellular elements in both tissues and, in the case of the atria, were accompanied by observable contractions. Functional cholinergic innervation from the autonomic ground plexus of the iris was elicited in both types of grafts by phasic retinal illumination. No evidence of immunologic rejection was found by histological analysis. Taken together, these data suggest that athymic rats may provide an appropriate host environment to study transplants of the central nervous and peripheral tissue from immunologically otherwise incompatible mammalian species.