الفهرس 
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Abstract
The present study aims to demonstrate the histological and immunohistochemical (IHC) alterations of T- cells in the thymus glands and spleen of hyperprolactinemia (HPRL) of adult male mice (Mus musculus) by using metoclopramide (MCP) for different durations. The mice were divided into five groups; group I: control mice injected i.p. with saline solution for 10 weeks, groups II, III, IV and V mice groups treated i.p. with MCP in a daily dose of 2.2 mg/kg/ b.w for different durations 2, 4, 7 and 10 weeks, respectively. A significant increase in the level of prolactin hormone and in the body weight of mice groups III, IV and V was recorded. HPRL mice group II for 2 weeks showed slight histological alterations in thymus tissues represented by relatively tenuous thymic atrophy as: the adipose tissue replaced few of the thymic tissue, decrease in cortical lymphocytic population, aggregation of cortical thymocytes forming Rosette- like formation, appeared with focal areas of macrophages; medulla became predominant over the cortex with proliferation of epithelial cells and increased lymphocytes population and it had some scattered relatively small sized cyst-like formation with pyknotic nuclei, and appearance of widen congested blood vessels. HPRL mice group III for 4 weeks illustrated a marked severe thymic involution represented by the decrement of total thymic mass and the replacement of most thymic tissue with adipose tissue, marked sever depletion in cortical lymphocytes population, extensive reduction in cortical thickness, and obviously increased numbers of huge cyst like formations with large vacuolated clear areas of lesion with tissue residues and with numerous macrophages. Formation of Hassall corpuscles were also seen in the medullary region which invaded with some fibroblasts, as well as the increased of adipocytes. While HPRL mice groups IV and V for 7 and 10 weeks illustrated clearly histological changes in the thymic tissues and their change were a time dependent.
IHC study expressed intense immunoreactivity to CD4+/ CD8+ T-cells (helper and cytotoxic T cells, respectively) in the thymus tissue of control group (I) while in all HPRL mice groups (II-V), CD4+/ CD8+ T-cells immunostain were markedly reduced. Image analysis of the mean percentage areas of both types of T cells immunostain expression recorded highly significant decrement in the thymic T cell population of all HPRL mice groups. Moreover, IHC study expressed immunoreactivity to CD68 macrophage in cortical thymocytes and some medullary thymocytes in thymus sections of control adult mice (group I). Furthermore, CD68 immunostaining was marked increased in hyperprolactinemia MCP treated adult mice groups (III, IV&V). while, CD68 immunostaining was decreased in hyperprolactinemia MCP treated adult mice groups (II). Image analysis of the mean percentage areas of CD68 recorded gradual increase starting after 4 weak of MCP administration, in which it recorded increase in group (III),significant increase in group (IV) and highly significant increase in groups (V) compared with control group. While it recorded decrease in group(II).
IgG In thymus sections of control adult mice (group I) showed that most IgG positive B cells was detected in distinct areas in cortex under the capsule and in medulla surrounding the blood vessels, they exhibited intense cytoplasmic staining. In addition , IgG was increased in HPRL, MCP treated adult mice groups (II&V) and was marked increased in HPRL, MCP treated adult mice groups (IV) .while, IgG immunostaining was decreased in HPRL, MCP treated adult mice groups (III). Image analysis of the mean percentage areas of immunoglobulin G (IgG) recorded increase in groups (II and V ) and significant increase in group (IV) compared with control group. While, it recorded a decrease in group (III) compared with control group.
Spleen of HPRL mice group II for 2 weeks showed obvious changes noticed in both red and white pulps. A large vacuolated areas with some lymphocytes were appeared all over the sections. Pyknotic picture was detected in red pulps as well as in PALS and in marginal zone which also became large with low intense of cellularity and also many giant cells were detected. HPRL mice group III for 4 weeks illustrated clear marked sever histological alteration in both red and white pulps. In which, many large vacuolated areas of lesion with some lymphocytes were appeared all over the sections. In addition, there was significant increase in macrophages, pyknotic nuclei, vesicular nuclei, giant cells, cell fragments in all splenic sections and some plasma cells. Moreover, The white pulp was detected with large dilated blood artery and vein which appeared with thick hyaline wall. While HPRL mice groups IV and V for 7 and 10 weeks illustrated marked histological changes in compared with spleen of control mice group I and their change were a time dependent.
IHC study expressed intense immunoreactivity to CD4+/ CD8+ T-cells in the spleen tissue of control group (I), while in HPRL mice groups (III) CD4+ T-cells immunostain were markedly reduced and were reduced in other HPRL mice groups. CD8+ immunostain was marked decreased in HPRL mice groups (III &V) & decreased in HPRL mice groups (II & IV). Image analysis of the mean percentage areas of CD4+ / CD8+ T-cells immunostain confirm the IHC study.
The CD68 immunoreactivity was detected as stained granules in macrophages in spleen sections of control adult mice (groupI). Furthermore, CD68 immunostaining was inecreased in HPRL, MCP treated adult mice groups (III, IV&V). While, CD68 immunostaining was slight decreased in hyperprolactinemia MCP treated adult mice groups (II).Image analysis of mean of percentage area of CD68 expression in the spleen of mice in the different groups recorded gradual increase starting after 4 weak of MCP administration, in which it recorded increase in group (III , IV&V) compared with control group. While, it recorded slight decrease in group (II).
In spleen sections of control adult mice (group I), most IgG positive B cells were detected in distinct areas under the capsule and in red pulp surrounding the blood vessels, they exhibited intense cytoplasmic staining. In addition, immunoglobulin G (IgG) was marked increased in hyperprolactinemia MCP treated adult mice groups (II) and was increased in hyperprolactinemia MCP treated adult mice groups (IV). While, IgG immunostaining was slight decreased in hyperprolactinemia MCP treated adult mice groups (III&V). Image analysis of the mean of percentage area of IgG expression in the spleen of mice in the different groups recorded significant increase in group (II) and increase in group (IV) compared with control group. While, it recorded slight decrease in group (III and V) compared with control group.
In conclusion, MCP caused an increase in prolactin levels causing HPRL which in turn led to histological and immunohistochmical changes in thymus glands and spleen, and such change were a time –dependent that finally led to atrophy of the thymus which accelerate thymic involution and immune senescence in spleen and subsequently weight gain. Also, the current study revealed that HPRL led to highly significant decrease in CD4+/ CD8+ T-cells and led to increase or decrease in CD68 macrophages and IgG expressions depending on time.
Recommendations, MCP must be used under medical supervision and MCP should not be used for long duration, and must be used with caution as a therapy. Additional studies of PRL and its regulation are needed in order to more understand the role of PRL in the physiology and pathophysiology of extra pituitary tissues, especially in the immune organs.