Immunocytochemical study of the subcommissural organ of rats with induced postnatal hydrocephalus

Abstract

The subcommissural organ (SCO)-Reissner's fiber (RF) complex of rats suffering from postnatal hydrocephalus was investigated immunocytochemically (peroxidase-antiperoxidase technique) by use of an anti-serum against bovine RF. Hydrocephalus was induced by injecting kaolin into the cisterna magna or by intracerebral infection with Borna disease virus. The kaolin-injected, hydrocephalic male rats were divided into two groups: (1) possessing an open communication between the fourth ventricle and the central canal of the spinal cord; (2) enduring an obliteration of this communication. In the latter group of rats the dilation of the ventricular cavities was far greater than in the former group. The Borna disease virus-infected female rats developed a severe hydrocephalus although in these animals all ventricular cavities and the central canal were in fully open communication. All rats belonging to the above-mentioned three groups displayed essentially the same alterations of their SCO-RF complex: (i) A reduction in the size of SCO and in the height of the ependymal secretory cells. (ii) A progressive disappearance of the immunoreactive hypendymal cells. (iii) The amount of AFRU-immunoreactive secretory material located in the rough endoplasmic reticulum was reduced. (iv) In contrast, the amount, location and immunoreactivity of the apical secretory granules did not undergo variations in comparison to sham-operated rats. (v) In the area of the SCO the layer of pre-RF material was thin or missing and a RF was not formed, and thus the central canal was also free of such secretory products. (vi) Clusters of AFRU-immunoreactive material were found attached to the wall of the Sylvian aqueduct.(ABSTRACT TRUNCATED AT 250 WORDS)

The subcommissural organ

“…Olsson (1958a) and Oksche (1961) postulated that the hydrodynamic of the aqueductal CSF plays a role in the aggregation of the secreted material in the form of a typical RF. This hypothesis is supported by the fact that hydrocephalic rats do not form an RF (Irigoin et al, 1990). However, a recent finding in our laboratory supports the view that a CSF factor different from its hydrodinamic would participate in the assembly of the proteins into RF: the rat SCO grafted into a lateral ventricle of an intact rat forms a typical RF (unpublished observation).…”

“…There is evidence that part of the SCO secretion released into the CSF remains soluble. Under certain physiological conditions, such as the embryonic period (chicken, rat, and human) and under specific experimental conditions, such as hydrocephalus, the SCO would secrete CSF-soluble compounds that do not form an RF, although they react with anti-RF sera (Irigoin et al, 1990;Schöebitz et al, 1993).…”

Hypertension effects on p73 expression in the rat circumventricular organs and cerebrospinal fluid

“…The human SCO has a great development during the foetal life [8,9], variations in the CSF and SCO have been reported in different kinds of hydrocephalus [4,10,11]. Alterations of the SCO in hydrocephalic mice and rats have been described, Takeuchi et al [12] de-scribes agenesis of the SCO and the posterior commissure (PC) in hydrocephalic mice, Irigoin et al [11], Rodriguez et al [4] and Carmona-Calero et al [7] found alterations in the secretion of the SCO in induced and spontaneously hydrocephalic rats. In addition, alterations in the secretions of cerebrospinal fluid proteins from the SCO have been described in spontaneously hypertensive rats [6].…”

Neuropathological Changes in Hydrocephalus—A Comprehensive Review

“…In regards to its main function, CSF overproduction by the choroid plexus is a rare a cause of hydrocephalus [3] [8] [241]. [252] and exhibits decreased glycoprotein immunoreactivity [253], and the subfornical organ can become damaged as the condition progresses [254].…”