تأثير عقار الديكساميثازون في غرس الكيس الارومي وغضروف و عظم الجنين وبعض المعايير الكيموحيوية في مصل دم الجرذان الحوامل .

Effect of Dexamethasone on blastocyst implantation, Cartilage ,bone embryo and some serum biochemical parameters in pregnant rats .

Dexamethasone (DX) is considered one of the steroidal drugs which have varieties of clinical application in medicine for treatment of many different   cases.

The present study was aimed to know the effect of DX on the implantation of blastocyst during the days 7 and ten of pregnancy, and the process of development of cartilage and bones in the fetuses of albino rats during the days 15 and 20 of pregnancy. In addition to that some physiological parameters aimed to be elucidated in the pregnant rats.

The study was conducted in the department of Biology College of Education for Pure Sciences/ University of Karbala in the period of April, 2016 to May 2017. Ninety four albino rats have been used, among them 10 male rats were used for matting with 84 female rats .The females were divided into three groups, with 28 rats for each group  . The first control group was injected with physiological normal saline (0.9%) intraperitoneally. The other two groups were received daily injection via the same route with 0.2 and 0.4 of DX 250 gm. of  body weight   respectively.

Each group was further subdivided into four subgroups with seven pregnant female rats for each one. The pregnant rats of each subgroup were sacrificed on the following days: 7,10,15, and 20 respectively The subgroups of the latter two days were used to study the development of the cartilage and bones. Half of the embryos on day 20 of pregnancy from the control and treated groups were used for histological sectioning; while the other half were used to stain the embryonic skeleton according to double staining technique of Whitaker and Dix .

All the collected samples which include the implantation sites from the pregnant uteri at days 7 and 10, together with whole embryos from days 15 and 20 of pregnancy, were put in two types of fixatives: 10% formalin and Boun’s solution. The collected samples then processed according to the traditional methods of paraffin embedding to be cut into sections of five µm thicknesses. The sections were stained by haemotoxylin and eosin (H&E); one step trichrome; periodic acid Schiff’s (PAS) with and without diastase; Alcian blue at pH 1.0 and 2.5.

Blood samples from pregnant rats were collected on days  7,10,15,and 20 of pregnancy to check for  the following biochemical parameters: concentration of calcium  ,phosphate and potassium ions ;alkaline phosphatase ,and acid phosphatase enzymes; and estimation of parathyroid and calcitonin hormones.

The results of the H&E stained section of pregnant sites of both the control and treated groups have shown that blastocyst was implanted in the antimesometrial side of the uterus. Most of this side of the uterus has become  decidualized tissue, where four zones could be identified: the primary decidual zone; secondary decidual zone ;implantation site; and undifferentiated decidual basal zone. On day 10 of pregnancy the embryos have shifted their position from the antimesometrial side to the mesometrial side of the uterus. The decidual tissue has grown wider and included most of stromal cells of the endometrium. The changing of the position of the embryos at day 10 is important for their survival because they will become nearer to the main blood supply to uterus which are running in the mesometrium.

The results of the one step trichrome stained sections from both the control and treated groups have shown clear distribution of collagen fibers in the decidual tissues at days 7 and 10 of pregnancy, which gave an indication of the success of pregnancy up to these stages. The primary decidual zone was devoid of collagen fibers but they are evident in the secondary decidual zone. At day 10 of pregnancy the collagen fibers were more in evidence especially at the mesometrial side of the uterus. The importance of collagen fibers was to give support to the blood vessels supplying the placenta which are coursing through the mesometrium.

Positive stain has been revealed in PAS reaction in decidual tissue on day seven of pregnancy without diastase, but it was negative with diastase. No reaction ,in the decidual tissue, with and without diastase was noticed at day ten of pregnancy. With Alcian blue pH 1.0 no reaction was noticed in the decidual tissue of both control and treated groups at days seven and ten of pregnancy. On the other hand positive reaction has come out at pH 2.5. The reaction at that pH was more prominent at the antimesometrial decidual tissue. But it was only depicted in the wall of blood sinusoid of the mesometrial decidual tissue.

Tongue like extensions of trophoblasts was noticed to be extending from the recently implanted embryo toward the endometrium, at day seven of pregnancy of both the control and treated group. The trophoblasts were pushing themselves in the direction of mesometrial decidual tissue in order to reach and settle nearer and in the wall of the blood sinusoids of that area. The invasion trophoblasts destination was to reach to the spiral arteries supplying the labyrinthine placenta in the rats.

At the 15th day of gestation there was no significant change in the cartilage model in the posterior limbs of the two treatment groups from the control group. The important signal indicated by the present study was observation of cartilaginous cell necrosis, hyperplasia and inflammatory cell infiltration, At the age of near the end of pregnancy in the treatment groups, many of the effects on the bone tissue, which are the existence of a vacuum around the bone cells and the infiltration of inflammatory cells in addition to bone erosion and arthritis and the reduction of cartilage and irregularity of medicine Surface area, hyperlipidemias and leavicular necrosis. Bone marrow squeaks in the control group and the first dose group of dexamethasone were found to be more extensive than the second treatment group. The bones of control group embryos stained with alizarin red has acquired much more red coloration than the treated group embryos, which indicated a slowdown of  ossification in their bones compared with control group, Showed that the length of the skull, spine, forelimbs and hind limbs of the fetal fetus at the age of 20 days of gestation of from the treatment groups has decreased for length in the control group but the decline was not significantly level (P <0.05) .

The calcium, phosphate and potassium ions concentration was low in the blood serum of treated group ( P< 0.05) during the whole period studied. However the phosphate ions  was low in the control group .

For the alkaline phosphatase level, it was significantly low ( P< 0.05) in the treated groups compare with the control. On the other hand the level of the acid phosphatase was high in the treated group ( P< 0.05).

The concentration of both the parathyroid and calcitonin hormones was significantly higher ( P< 0.05)  in the treated groups compared with control.

In conclusion, the present study has revealed that DX treatment showed no interference with the process of implantation during the days seven and ten, and with chondrogenesis on day fifteen of pregnancy.  While the effect on cartilage formation on the fifteenth day and bone on the twentieth day of pregnancy.

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