Archive for the ‘Postnatal Rat Testis’ Category


DISCUSSION(8)

This correlates to p.n. Day 14 and p.n. Days 17-18 in the mouse, meaning acquisition of early and late pachytene spermatocytes, respectively. Haploid round spermatids were first detected by p.n. Days 2425, corresponding to p.n. Days 20-21 in the mouse; elongating spermatids started to accumulate by p.n. Days 3031 (as evidenced by cells that began to occupy the R7 region in the first window), corresponding to p.n. Days 2425 in the mouse; and rat pups older than 36 days seem to have condensed spermatids in their testes (as evidenced by the first signs of cells within the R5 group), corresponding to pups older than 27-28 days in the mouse. This rat testicular developmental schedule in comparison to that for the mouse is summarized in Table 2. It is noteworthy that the similarity between the rat and mouse along the eight developmental stages is not confined to the flow cytometric picture but includes also the proportion of the various cell types within each developmental stage (Table 1). Nevertheless, the stoichiometry of the various cell types varies among reports and this study), suggesting that the specific analysis procedure is an important parameter that should first be normalized when quantitative assessment is made. This is important, for example, when FACS is used to determine the efficiency of spermatogenesis in response to hormonal manipulation. buy ortho tri-cyclen online

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  • In the rat, a very similar acquisition pattern for the various subpopulations, composed of the same eight developmental stages, was found. As in the mouse, rat testis at p.n. Days 6-7 contains only mitotically dividing spermatogonia cells and somatic cells, some of which are still undergoing mitotic divisions. The developmental stage of p.n. Days 13-14 in the rat correlates to p.n. Day 10 in the mouse in the sense that it is the last postnatal age showing no increase in the proportion of 4d cells, although mitotic activity of the somatic cells either ceased or at least dramatically declined. This suggests that, as in the mouse, the rather constant portion of 4d cells is attributable to primary spermatocytes that have entered the leptotene stage of prophase I. ventolin inhalers

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  • DISCUSSION(6)

    It is noteworthy that although the mouse testicular developmental schedule obtained in the present study is similar to the morphologically based developmental schedule reported by Bellve et al., there is an advantage to determining the FACS pattern of each developmental stage. This enables an efficient separation of the various subpopulations at each developmental stage (with purity more than 90%) and hence analysis of stage-specific events. For example, we were able to obtain a very pure population of early round spermatids from p.n. flovent inhaler

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  • At p.n. Day 10 (stage II), although the FACS pattern seemed unchanged in both the FSC-H and the FL2 parameters, the constant portion of 4d cells (~3%)—despite thegreatlyre-duced frequency of mitotically dividing somatic cells—is consistent with cells of the first spermatogenic wave reaching the leptotene stage of prophase I. There are no R1 cells (in the first window) in this developmental stage, since lep-totene spermatocytes are small cells. As the developmental process progresses, more cells from the first spermatogenic wave enter prophase I. buy levaquin online

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  • DISCUSSION(4)

    A morphologically based determination of the mouse testicular developmental schedule was documented by Bellve et al.. According to this developmental schedule, seminiferous epithelium from p.n. Day 6 pups contains only primitive type A spermatogonia and Sertoli cells. At p.n. Day 8, type A and type B spermatogonia are present, and by p.n. Day 10, cells from the first spermatogenic wave can be found at preleptotene and leptotene stages of the first meiotic prophase. Zygotene primary spermatocytes are first detected on p.n. Day 12, and early pachytene and late pachytene spermatocytes first appear on p.n. buy asthma inhaler

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  • A flow cytometric follow-up on the development of the postnatal testis has been executed in the past in both the mouse and rat. However, these studies focused on the changes in the DNA content of the cells without further staging within each DNA containing group, especially within the 4d group. Concerning changes in the DNA content, the results reported in the present study on the mouse are in accordance with those of Janca et al.. Regarding rat spermatogenesis, Zhengwei et al. reported that primary spermatocytes first appear on Day 15 and round spermatids on Day 25. buy ampicillin

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  • DISCUSSION(2)

    The 2d cells, having intermediate FSC-H values and consisting of somatic cells, secondary spermatocytes, and spermatogonia cells at the G1 stage of the cell cycle (although at a very small proportion, as mentioned above), exhibited two subpopulations based on their SSC-H values (R3 and R4). On the basis of morphological characteristics, we were not able to conclusively associate these two subpopulations with specific testicular cells. Nevertheless, the SSC-H differences between these two subpopulations, which are more apparent in earlier developmental stages, might result from differences in biochemical activities. buy asthma inhalers

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  • In this study we used four-parameter flow cytometry to determine the testicular developmental schedule in the rat as compared to that of the mouse. Using the FSC-H/SSC-H parameters, we were able to determine seven distinct subpopulations (R1-R7) that were divided into four major levels of fluorescence (Figs. 1 and 2). The positive correlation between the size of the cells (FSC-H) and the DNA content (FL2-A), demonstrated by the fact that the cells with the highest FSC-H values (R1 and R2) were those containing 4d DNA and that the cells with the intermediate FSC-H values (R3 and R4) were those containing 2d DNA, is in agreement with the results reported by Bellve et al.. The R1 and R2 subpopulations consist of primary spermatocytes that have gone through premeiotic DNA synthesis and have entered meiotic prophase I. buy prednisone

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