J Physiol Pharmacol 2002;46 (4);
Formation, Morphology and Fate of Multinucleated
Cells (Symplasts) in the Rat Testis Exposed to 5-Fluorouracil
(Received on May 15, 2002)
URBAN J. A. D’SOUZA AND NARAYANA. K.* Department
of Anatomy* and physiology,
Kasturba medical college,
Centre for basic Sciences, Bejai,
Mangalore – 575 004
(5-FU) is extensively used to treat tumours of head and neck, breast
and gastrointestinal system. Despite its clinical efficacy it is
cytotoxic and induces the cell death (1), and generates DNA strand
breaks in mammalian cells (2). It was previously reported that 5-FU
affects the cytoarchitecture of spermatids (3). Recently, we have
reported that 5-FU induces the formation of abnormal germ cells,
epithelial sloughing (4), decrease in testis weight and tubular
atrophy (5). However, the mechanism of formation, morphology and
fate of abnormal germ cells have not been previously described in
5-FU treated rats.
the present study, 5 male Wistar rats (11 weeks old; 130-150 g body
weight) were housed in plastic cages with paddy husk bedding. They
were maintained under controlled temperature and humidity. Rats
were treated with the single dose of 100 mg/kg (i.p.; Fluracil,
Biochem, Mumbai), as this dose level is known to induce the abnormal
cells after 72 h post exposure (4). At 72 h, the testes and epididymes
were dissected and prepared for light microscopical studies according
to the procedure explained in our previous reports (4, 5). Paraffin
sections were stained with H & E and periodic acid-Schiffs’s
reaction–haematoxylin (PAS-H) (6). These sections were screened
to evaluate the percentage incidence of tubules with abnormal cells
and number of nuclei/multinucleated cell (MNC). Diameters of 10
large and 10 small sized MNCs were measured by an ocular micrometer
calibrated with the stage micrometer. The processes of MNC formation
in the testis and its degeneration in the testis as well as in the
epididymis were studied.
were found in the seminiferous epithelium, lumina of tubules and
in the epididymis. Epithelial sloughing showed a positive correlation
with the number of MNCs. Some MNCs showed 2 or 3 nuclei, representing
the ongoing process of cell union in the epithelium. The MNCs were
found in 39% of tubules. In 3 testis examined from 5 animals, the
MNCs were observed. Incidence of MNCs ranged from 1-14/tubule and
the mean nuclei/MNCs was a 7.0 ±
2.83 (SD) with a range of 3-11. Mean diameters of small a large
sized MNCs were 53.2 ± 9.84 (SD) (range 13.3-66.5) and 85.12 ± 5.25 (SD) (range 79.8-156.0) m respectively. Nuclei of these MNCs resembled
the spermatid nuclei, but with the chromatin margination. Between
the nuclei no membrane residues were observed, however a reticulum
of cytoplasm mass was present. Some cells showed empty spaces. In
the testis, the MNCs showed degeneration (Fig. 1) which continued
even in the epididymis. In the epididymis the symplasts and other
sloughed cells showed altered morphology. All the nuclei of MNCs
joined together to form a single large basophilic mass (Fig. 2)
and in other exfoliated germ cells nuclei showed the degeneration.
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imparts its cytotoxicity by incorporating into RNA or DNA and inhibiting
the activity of thymidylate synthetase (7). It arrests the cell
cycle, induces the abnormal germ cell development and malorientation
of spermatids in the rat testis (3, 4) and epithelial sloughing
(8). Epithelial sloughing is mainly due to the Sertoli cell damage
and interruption of intercellular bridges. Formation of MNCs in
5-FU treated rats therefore indicates its damaging effect on the
Sertoli cells and intercellular bridges. Cells with 3-11 nuclei
also indicates that sloughed germ cells especially the spermatids
join together to form the MNCs. Chromatin margination in these MNCs
either in the testis or epididymis is an indicator of cell degeneration.
The MNCs, consequently reached the epididymis and the nuclei of
these cells gradually disappeared due to degeneration. These cells
could further migrate into the rest of the reproductive tract, or
in due course could be phagocytosed either in the epididymis or
elsewhere. These degenerating cells were PAS positive bodies with
well defined outline. We conclude that 5-FU affects the Sertoli
cells and intercellular bridges in the rat testis. This study also
concludes, that the MNCs were formed due to the cell union, and
they degenerate in the testis and epididmis.
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