Myoid cell proliferation in rat seminiferous tubules after ischaemic testicular atrophy induced by epinephrine. Morphometric and immunohistochemical (bromo‐deoxyuridine and PCNA) studies*

Abstract

The proliferation of peritubular myoid cells in the testes of rats treated for 1-11 weeks with intra-scrotal injections of epinephrine was investigated using immunohistochemistry and quantitative histology. The percentage of peritubular cells that were immunopositive for proliferating cell nuclear antigen (PCNA) or that were labelled with 5'-bromodeoxyuridine (BrdU) in the S-phase of the cell cycle, were calculated in control and treated rats after 1,3,5,8 and 11 weeks of treatment. In addition, the change in the number of peritubular cells per testis was calculated using two different stereological methods. The possible correlation between the changes observed using the two proliferation indices (PCNA immunoreaction and labelling of BrdU) in peritubular myoid cells was evaluated by regression analysis. The results of the study indicate that both proliferation indices increased in peritubular cells between the third and the eighth weeks of treatment, and that this increase was correlated with an increase in the number of these cells. From weeks 8-11 of treatment, both proliferation indices decreased and the same occurred with the number of peritubular cells. We hypothesize that proliferation of the peritubular cells occurs in order to increase their secretion of extracellular matrix components leading to enlargement of the lamina propria of the seminiferous tubule.

Immunohistochemical quantitative study of the peritubular lamina propria after induction of testicular atrophy induced by epinephrine

“…The increase in fibronectin immunostaining detected at the end of experiment in the present study may be related to the synthesis of type I collagen, which is abundant in the tubular lamina propria (Hadley & Dym, 1987). This collagen production, together with the increased formation of laminin and fibronectin, would be involved in enlargement of the tunica propria and fibrosis reported previously in epinephrine-treated rat testes at advanced stages of the experiment (Santamaria et al, 1995). .…”

“…The cooperation between Sertoli cells and peritubular myoid cells in the synthesis of extracellular matrix components of the tubular lamina propria, including glycosaminoglycans, collagen and laminin, is well known (Raychoudhury et al, 1992(Raychoudhury et al, , 1993a. A previous study of epinephrine-treated rat testes, using BrdU labelling, showed that the proliferation rate of peritubular myoid cells increase4during the first 8 weeks of treatment and decreased thereafter (Santamaria et al, 1995). Perhaps peritubular cell proliferation inhibits other functions of these cells, including their cooperation with Sertoli cells, which would temporarily decrease laminin synthesis; this would then return to normal values when proliferation ceased.…”

“…A previous report has demonstrated an increased rate of proliferation of peritubular myoid cells in testicular atrophy induced in rats by epinephrine. This finding has been interpreted as a reactive process by these cells, which then increase their secretion of extracellular matrix components and enlarge the tubular lamina propria (Santamaria et a/., 1995). Some components of the peritubular lamina propria, including extracellular matrix proteins and myoid cells, may be qualitatively or quantitatively altered by the ischaemic lesion caused by epinephrine.…”

Histological development of human testicular cords from 70 to 90 days of gestation

“…In the human adult testis, PCNA-staining are consistently detected in spermatogonia and early spermatocytes but hardly detected in the interstitial cells (Hall et al, 1990). However, PCNA can be also used as a marker for proliferation of testicular interstitial cells (Santamaria et al, 1995;Tauber et al, 1995;Schlatt et al, 1999;Murray et al, 2000). In the present study, it was found that not only germ cells but also other testicular cells during 70-90 days of gestation had been detected by a positive PCNA monoclonal antibody reaction.…”

Testicular histomorphometry and the proliferative and apoptotic activities of the seminiferous epithelium in Syrian hamster during spontaneous recrudescence after exposure to short photoperiod

“…We chose three 5‐m sections (25 random fields per section) and calculated following histomorphometric variables using the Cell D Olympus image analysis software: (i) the volume density of seminiferous tubules (VD ST ), as the seminiferous tubule surface/reference area (142,049.28 m 2 ) ratio; (ii) the testicular interstitium volume density (VD TI ), as the ratio of interstitium surface/reference area (142,049.28 m 2 ) ratio; (iii) the total volume of seminiferous tubule per testis ( V ST ) multiplying VD ST V T ; and (iv) the length of seminiferous tubule per volume unit ( L v ) using the established formula: L v = VD ST / R 2 (Santamaría, Martín, Codesal, & Paniagua, ). In addition, for the total length of seminiferous tubules ( L ST ), we assumed that all tubules form a single cylinder with a length L , a radius R (MTD/2) and a volume V ST .…”