Strukturne i funkcionalne promene paraštitastih žlezda i bubrega nekon primene steroida, izoflavona i kalcijuma u animalnom modelu andropauze
Structural and functional changes of parathyroid glands and kidneys after treatment with steroids, isoflavones and calcium in an animal model of the andropause
2013
Authors:
Živanović, Jasmina B.Contributors
Filipović, BrankoČakić-Milošević, Maja
Milošević, Verica
Šošić-Jurjević, Branka
Ajdžanović, Vladimir
Document Type:
Doctoral thesis (Published version)
Metadata
Show full item recordAbstract:
Andropause is defined as a gradual decline of serum testosterone concentration during
ageing, which is related to an increased incidence of cardiovascular diseases, benign and
malignant prostate diseases and osteoporosis. Using steroid hormones, as well as
vitamin D and calcium in the treatment of osteoporosis and other ageing symptoms, in
both genders, have some undesirable side effects, such as increased risk of
cardiovascular diseases, hyperphosphaturia and prostate cancer.Taking into account the
potentially harmful aspects of the hormone replacement therapy, an increasing emphasis
is placed on the alternative, plant-originated therapeutics for osteoporosis.
Accumulating evidence suggests that soy isoflavones may represent a promising
alternative remedy for aging symptoms in both genders.
This study aimed to examine the effects of steroids, isoflavones and calcium on the
structural and functional changes in parathyroid glands and specific functional proteins
in the kidney tubules, responsible for Ca and Pi regulation, in an animal model of the
andropause, and to determine their potential impact in the preservation of mineral
metabolism impaired with ageing.
Fifthteen-month-old Wistar rats were orchidectomised (Orx) or sham (SO) operated
under ketamine anesthesia. After 2 weeks of recovery, Orx animals were divided into
experimental groups and treated subcutaneously with testosterone-propionate (5 mg/kg
b.w.; TP), estradiol-dipropionate (0.625 mg/kg b.w.; EDP), vitamine D (50 μg/kg b.w.;
Vit D), genistein (30 mg/kg b.w.; G), daidzein (30 mg/kg b.w.; D) or calcium
intramuscularly (28.55 mg/kg b.w.; Ca) every day, for 3 weeks. Every treated group had
a coresponding SO and Orx control groups treated with the proper amount of vehicle,
following the same regime. Animals were fed a soy-free diet with corn oil as the fat
source. The rats were decapitated 24h after the last injection, parathyroid glands and left
kidneys were excised, their weight was measured and they was processed for light and
electron microscopic examinations. Techniques of histochemical staining and
immunohistochemical labeling, transmission electron microscopy, and stereological
analyses were performed. Gene expression levels were determined with Real-time PCR.
Concentrations of PTH, Ca2+, Pi and creatinin levels in serum and concentrations of
Ca2+, Pi and creatinin in urine were determined biochemically. The obtained data were
statistically processed.
The volume of parathyroid glands in Orx rats was increased compared to the SO group.
After treatments with TP, EDP or Vit D the parathyroid glands volumes were decreased,
when compared to Orx animals. The volume density of chief cells after treatment with
EDP was decresed, while the volume density of interstitium was increased, comparing
to Orx rats. Treatment with genistein led to an increase of parathyroid gland volume,
while treatment with daidzein decreased the same parameter, with regards to Orx group.
The volume densities of chief cells were decreased after treatments with genistein or
daidzein, while the volume densities of interstitium were increased, in comparison with
Orx animals. Administration of calcium to Orx rats provoked the reduction of
parathyroid glands volume, while the volume density of interstitium after same
treatment was increased, comparing to the Orx rats. The lack of steroid hormones,
provoked by Orx, led to the increment of serum PTH, when compared to the SO control
group, while treatments with TP, EDP, Vit D, genistein, dadizein or calcium decreased
the mentioned parameter, comparing to the Orx group. NaPi 2a expression in Orx
animals was reduced in regards to its abundance in SO animals, although it was
increased in TP, Vit D, genistein or daidzein groups, compared to the Orx rats. The
treatment with EDP attenuated NaPi 2a expression, in comparison with Orx group. In
Orx rats, the staining for PTH1R was stronger when compared to SO group, while the
treatments with TP, Vit D, genistein, daidzein or calcium induced reduction of the
PTH1R immunofluorescence, compared to Orx animals. The intensity of the PTH1R
signal after EDP treatment was slightly reduced in regards to its abundance in Orx
group. FGFR and Klotho receptor expression weren’t significantly changed in Orx
animals, when compared to the SO controls. After treatment with EDP, the expression
of FGFR and Klotho receptors was increased, when compared to the Orx rats.
Administration of genistein or daidzein caused the decrease in FGFR expression level,
compared to Orx animals. Genistein treatment of Orx rats induced enhancement of
Klotho receptor expression level, while daidzein treatment decrease it, in comparison
with Orx rats. In Orx animals, Ca2+ and Pi serum concentrations were decreased, while
urine Ca2+ and Pi content was increased, in comparison with the SO control. After
treatments with TP, EDP, Vit D, genistein, daidzein or calcium serum
Ca2+concentrations were increased, when compared to Orx animals. Treatments with
TP, genistein, daidzein or calcium induced the increment of Pi serum concentrations,
with regards to Orx rats. Aplication of TP, EDP, Vit D, genistein, daidzein or calcium to
Orx rats led to decrease Ca2+ urine concentrations, comparing to Orx animals. Urine Pi
concentrations after treatment with Vit D, genistein, daidzein or calcium were
decreased, while EDP treatment induced enhancement of Pi urine concentration, with
regards to Orx rats.
Our results showed that the treatments with steroids, isoflavones and calcium of
andropausal male rats demonstrate some differences in the level of the same direction
effects, demarcating widespread, commonly used therapies and alternative approaches
in the regulation of Ca2+ and Pi homoestasis. Application of isoflavones led to the
stronger increment in abundance and the expression level of NaPi 2a cotransporter,
intensively decreased the presence of PTH1R, abundance and expression of FGFR in
the kidney tubules was noticeable reduced, and decreased the concentrations of Ca2+
and Pi in urine, as well as more pronouncely increased the concentrations of Ca2+ and Pi
in the serum, when compared to the milder effects of treatments with steroids and
calcium. The listed changes may reestablish mineral homeostasis, disturbed by the
aging process.
Keywords:
Andropause; Steroids; Isoflavones; Calcium; Parathyroid gland; NaPi 2a; PTH1R; FGFR; Klotho receptorSource:
University of Belgrade, Faculty of Biology, 2013, 1-116Funding / projects:
- The effects of select plant extracts, phytoestrogens, steroid and peptide hormones on the rat neuroendocrine system (RS-MESTD-Basic Research (BR or ON)-173009)
URI
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http://nardus.mpn.gov.rs/123456789/2116
https://radar.ibiss.bg.ac.rs/handle/123456789/2433