دراسة نسيجية ووظيفية لتأثير إزالة المبايض في الغدة النخامية، والرحم والغدة اللبنية في الأرانب المحلية Oryctolagus cuniculus

Study histological and physiological effects of Ovariectomy on pituitary, uterus and mammary gland in local rabbits.(Oryctolagus cuniculus)

    This study aimed to investigate the effect of bi- and uni- lateral ovariectomy on mammary gland, uterine tissues and pituitary gland in female rabbits Oryctolagus cuniculus. Forty eight animals were divided randomly into two groups, one of them at virgin stage and anther at lactating stage. Each group subdivided into four groups (control(sham)) the first group , second one (bilateral ovariectimized) group ,the third and fourth groups (left and right unilateral ovariectomized ) respectively , (6 rabbits in each group). Thereafter, the animals were sacrificed after a month of operation to provide mammary, uterine and pituitary tissues for the histological, histochemical ,imunohistochemical and morphometrical studies .
Blood samples were collected for biochemical tests including Estrogen , Progesterone , Prolactin , Follicle stimulating and Luteinizing hormones concentration and LH hormons concentration in pituitary tissue, Malondialdehyde and Reduced Glutathion in serum .The Alkaline phosphatase and 5 – Nucleotidase in mammary and uterus tissue. The following results were obtained:
– Histological section with hematoxylin and eosin stain of mammary
gland in bilateral ovariectomy of virgin animals revealed that decrease in the size of lobules and alveoli with less dilated and increase in adipose tissue compared with their control, while in lactating rabbits bilateral ovariectomy animal showed small lobules containing less branching alveoli with in inactive alveoli and increased in stroma. Staining sections with trichrome have revealed there is excessive amount of collagen fibers in the stroma of the mammary gland tissue in all treatment groups of lactating and virgin in comparison with their controls.
Beside that histochemistry studies of the Periodic Acid Schiffʹs (PAS) staining showed a positive reaction in histological section of mammary tissue in all groups of lactating stage, while the virgin groups showed a negative reaction to the PAS stain. On the other hand , there is a significant decrease(p<0.05) in the diameters and numbers of alveoli in all treatment groups in compared with their controls.
Histological study of the uterus sections showed many changes caused by bilateral ovariectomy , this included: decreased in thickness and folded with atrophy of uterus layers , absence of uterine glands and infiltration of inflammatory cells in compared with other groups in virgin and lactating stages. While trichrome stained sections showed an excessive amount of collagen fibers in the uterus in all treatment groups in compared with their controls.
Histological section with hematoxylin and eosin stain of pituitary gland in bilateral ovariectomy of virgin and lactating groups showed no pathological changes ,in addition , the staining with immunohistochemical stain of progesterone receptors in gonad cell showed large cells with vacuoles in their cytoplasm in bilateral ovariectimized in compared with other groups .
The estrogen and progesterone receptors expression in mammary and uterine tissue of animals treated in virgin and lactating treated groups showed weakly positive (+) stain reactions and no expression(-) of estrogen and progesterone receptors in the mammary and uterus tissue of bilateral ovariectomized virgin group. Weak expression(+) of estrogen and progesterone receptors in mammary tissue, no expression (-) of estrogen receptors and weak expression (+) of progesterone receptors in uterus tissue of lactating group. The virgin and lactating showed a strong expression (+ + +)(++) for estrogen and progesterone receptors The mammary and uterus tissue respectively in right unilateral ovariectomy , and moderate positive (++), weakly positive stain reaction (+) to estrogen receptors and progesterone receptors in the mammary and uterus in of virgin and lactating groups of left unilateral ovariectomy .
The results showed a significant increase (p<0.05) in the level of hormones (FSH, LH) in bilateral ovariectomized groups for two physiological stages( virgin , lactating ) compared to their control. In addition, there is no significant differences in prolactin hormone level in treatment groups for virgin compared with control (sham), while the prolactin hormone level significantly increased (P<0.05) in right removal of ovarian in lactating stage ,significant decrease (P<0.05) in the concentration of progesterone and estrogen hormone in bilateral ovariectomized groups for virgin and lactating stages compared with their controls .The significant decrease (P<0.05) showed in the level of LH hormone in the pituitary gland tissue.
Significant decrease (P<0.05) in the level of alkaline phophatase enzyme (ALP) and 5,- Nucleotidase enzyme (NTD) in bilateral ovariectomized group in virgin , lactating groups compared to the control in the mammary and uterus tissue.
The present study showed a significant decrease (P < 0.05) in the serum concentration of reduced glutathione (GSH) and a significant increase (P<0.05) in the serum malondiaaldehyde (MDA) concentration in ovariectomized groups for two physiological (virgin , lactating) compared with control. In conclusion , the bilateral ovariectomy caused histological , histochemical and physiological changes in the mammary ,uterus and pituitary tissue in virgin and lactating groups of female rabbits.