Effects of melatonin and metformin on the ovaries of rats with polycystic ovary syndrome

OBJECTIVE

To study the combined and isolated effects of melatonin and metformin in the ovarian tissue of rats with PCOS.

DESIGN

Experimental study using a rat model of PCOS induced by continuous light exposure.

INTERVENTION(S)

Forty adult female rats were divided into 5 groups: physiological estrus phase (Sham); permanente estrus with PCOS induced by continuous lighting exposure for 60 consecutive days (control); with PCOS treated with melatonin; with PCOS treated with metformin; with PCOS treated with melatonin + metformin. After 60 days of treatments, all rats were killed, and ovaries were collected and processed for paraffin-embedding. Formalin-fixed paraffin-embedded sections were stained with hematoxylin and eosin or subjected to immunohistochemistry for proliferation (Ki-67) and apoptosis (cleaved caspase 3) detection markers.

SETTING

Federal University of São Paulo, Brazil.

ANIMALS

Forty adult female Wistar rats (Rattus norvegicus albinus).

MAIN OUTCOME MEASURE(S)

Number of corpus luteum and ovarian cysts, number of ovarian follicles (primary and antral follicles), number of interstitial cells, percentage of ovarian follicles (primary and antral follicles), and of interstitial cells immunostained to cleaved caspase-3 and Ki-67.

RESULTS

Absence of corpus luteum, a higher number of cysts, and increased nuclear volume and area of interstitial cells, along with a decrease in primary and antral follicle numbers, were noticed in the control group compared with the Sham group. Melatonin and metformin treatments attenuated these effects, although the combined treatment did not mitigate the increased number of cysts and ovaries induced by PCOS. An increase in theca interna cell apoptosis was observed in the control group, whereas melatonina and metformin treatments reduced it significantly. A higher percentage of caspase-3-immunostained granulosa cells was noted in the Sham and all treated groups compared with the control group; no aditive effects on ovarian cell apoptosis were observed in the combined treatment. The percentage of Ki-67- immunostained granulosa cells was significantly higher in the control group compared with the Sham group. However, the combined treatment, not melatonin and metformin alone, mitigated this effect. A higher percentage of Ki-67-immunostained interstitial cells was observed in all treated groups compared with the Sham and control groups, whereas no additive effects in that immunoreactivity were observed in the combined treatment.

CONCLUSIONS

Melatonin and metformin may improve ovarian function in rats with PCOS. The combined melatonin and metformin treatment is more effective in attenuating excessive granulosa cell proliferation, but it is not more effective in improving ovarian function than these drugs applied alone in rats with PCOS.

Histomorphometric and immunohistochemical changes in interstitial cells and ovarian follicles of rats with polycystic ovaries treated with clomiphene citrate

OBJECTIVE

To evaluate the histomorphometric and immunohistochemical changes in interstitial cells and ovarian follicles of rats treated with clomiphene citrate during and after induction of permanent estrus.

METHODS

Twenty four adult-female rats with regular estrous cycle were equally divided into three groups: (1) GCtrl-at estrous phase. (2) GPCOS-at permanent-estrous phase. (3) GCC-PCOS rats, which remained exposed to 60 days of continuous illumination and treated with Clomiphene Citrate. After that, the animals were euthanized, and the ovaries were removed and processed for paraffin embedding. Sections were stained with H.E. for histomorphometry or subjected to immunohistochemistry for Ki-67 and cleaved caspase-3 detections.

RESULTS

The GPCOS showed lack of corpus luteum and several ovarian cysts, as well as interstitial-like cells. The presence of corpus luteum and a significant increase in primary and antral follicles were observed in GCC, which also showed a decrease in the number of ovarian cysts and in the area occupied by interstitial-like cells, as well as a decrease in nuclear volume of interstitial cells. The percentage of cell proliferation was significantly higher in granulosa cells of the GCC. On the other hand, the percentage of apoptosis was significantly higher in the granulosa cells of GPCOS than the GCC.

CONCLUSION

The ovaries of rats treated with clomiphene citrate showed a decrease in the number of cysts, an increase in the number of ovarian follicles, the presence of corpus luteum along with a decrease in the nuclear volume in the area occupied by interstitial cells.

Electromyographic analysis of muscle activation of the trunk and lower limbs during human gait and hippotherapy using different ride mount materials

OBJECTIVE

Activation of the trunk and lower limb muscles, namely the multifidus, rectus abdominis, rectus femoris, and tibialis anterior, was analyzed using surface electromyographyin 40 young, healthy, and sedentary individuals.

METHODS

Data were collected from sneaker-clad subjects with independent gait and during hippotherapy using saddles and blankets, with the feet in and out of the stirrups.

RESULTS

Surface electromyography results demonstrated a statistically significantly greater activation of the rectus femoris comparison to tibialis anterior muscle during hippotherapy. No statistically significant differences were observed when comparing variables related to the mount materials used in hippotherapy and human gait.

CONCLUSION

In this study, similarities were observed between activation of the trunk and lower limb muscles during hippotherapy and human gait. In addition, the mount materials and practices used in hippotherapy did not influence muscle activity.

Is the inferior occlusal plane a reliable anatomic landmark for inferior alveolar nerve block? A study on dry mandibles of Brazilian adults

PURPOSE

To investigate the relationship between the mandibular foramen (MF) and the inferior occlusal plane (IOP) of anatomic specimens, in order to guide clinicians in the inferior alveolar nerve block (IANB).

METHOD

Eighty-two dry mandibles (totally or partially toothed) of Brazilian adults were selected, totalizing 66 left and 66 right antimeres. A flat plate of rigid PVC plastic was placed on the occlusal surfaces of posterior teeth and pressure was then manually applied to simulate the IOP. Following, the perpendicular distance from the IOP to the lowest point of the MF was measured by the use of a digital caliper, adopting negative values inferiorly and positive values superiorly.

RESULTS

Regarding the antimeres, the majority of the lowest limits of the MF was below the IOP (right: 86.4%, left: 81.8%) with a mean of -4.2mm (±4.8) in the right and -4.1mm (±4.8) in the left ones, without any statistical significance. Considering both sexes, no statistically significant difference was obtained between them.

CONCLUSION

The IOP seems not to be a good anatomical landmark to localize the MF and, its turn, to guide clinicians during the IANB for Brazilian adults, given the marked topographic variations.

Melatonin may prevent or reverse polycystic ovary syndrome in rats

OBJECTIVE

To evaluate the ovarian effects of melatonin (Mel) in a rat model of polycystic-ovary-syndrome (PCOS) before and after permanent estrus induction.

METHODS

Thirty-two adult-female rats with regular estrous cycle were equally divided into four groups: 1) GCtrl - at estrous phase. 2) GPCOS - at permanent-estrous phase. 3) GMel1 - treated for 60 days with Mel (0.4 mg/Kg) during permanent estrus induction and 4) GMel2 - rats with PCOS and treated for 60 days with Mel. After that, the animals were euthanized, and the ovaries were removed and processed for paraffin embedding. Sections were stained with H.E. for histomorphometry or subjected to immunohistochemistry for Ki-67 and cleaved caspase-3 (Casp-3) detections.

RESULTS

The GPCOS showed lack of corpus luteum and several ovarian cysts, as well as interstitial-like cells. The presence of corpus luteum and a significant increase in primary and antral follicles were observed in Mel-treated groups, which also showed a decrease in the number of ovarian cysts and in the area occupied by interstitial-like cells. These results were more evident in GMel1. The percentage of Ki-67-positive cells was significantly higher in the Mel-treated groups, mainly in the GMel2, as compared to GPCOS. On the other hand, the percentage of Casp-3-positive cells was significantly lower in granulosa cells of GMel1, whereas it was significantly higher in the interstitial-like cells of GMel2, in comparison to GPCOS.

CONCLUSION

Melatonin administration prevents the permanent estrus state in the PCOS rat model. This effect is more efficient when melatonin is administered before permanent estrus induction.

Evaluation of retromolar canals on cone beam computerized tomography scans and digital panoramic radiographs

PURPOSE

The purpose of this study was to carry out morphologic and topographic analyses of retromolar canals on cone beam computerized tomography (CBCT) scans, comparing findings to others obtained from the corresponding digital panoramic radiographs.

METHODS

Sixty-one CBCT scans were analysed digitally, as well as their corresponding digital panoramic radiographs. The prevalence and distribution of these canals, foramen diameters, and intraosseous communications were also evaluated.

RESULTS

On CBCT scans, we found that 24.6% of individuals had at least one retromolar canal. The mean foramen diameter was slightly higher than 1 mm and we could not determine the intraosseous anatomical connections in most cases. The morphology and topography of the retromolar canals were not affected by gender and antimere. In addition, only 22.2% of all tomographically identified canals could be confirmed on digital panoramic radiographs (26.7% of such patients). Regarding all sample, 6.6% of individuals showed retromolar canals on digital panoramic radiographs.

CONCLUSION

We may consider that these structures are clinically relevant findings and, due to the low accuracy of the panoramic radiographs, high-quality tomographic exams should always be asked for presurgical treatment planning.

Immunohistochemical evaluation of proliferation, apoptosis and steroidogenic enzymes in the ovary of rats with polycystic ovary

Objective: to evaluate the immunohistochemical expression of proliferative, apoptotic and steroidogenic enzyme markers in the ovaries of rats with polycystic ovary syndrome (PCOS). Methods: twenty rats were divided into two groups: GCtrl - estrous phase, and PCOS - with polycystic ovaries. The GCtrl animals were subjected to a lighting period from 7 am to 7 pm, while the animals with PCOS group remained with continuous lighting for 60 days. Subsequently, the animals were anesthetized, the ovaries were removed and fixed in 10% formaldehyde, prior to paraffin embedding. Sections were stained using H.E. or subjected to immunohistochemical methods for the detection of Ki-67, cleaved caspase-3, CYP11A1, CYP17A1 and CYP19A1. The results were analyzed using Student's t-test (p < 0,05). Results: morphological results showed evidence of interstitial cells originating from the inner theca cells of degenerating ovarian cysts in PCOS. Immunoexpression of Ki-67 was higher in the granulosa cells in GCtrl, and the theca interna cells in PCOS, while cleaved caspase-3 was higher in granulosa cells of ovarian cysts from PCOS and in the theca interna cells of GCtrl. Immunoreactivity of CYP11A1 in the theca interna, granulosa and interstitial cells was similar between the two groups, while CYP17A1 and CYP19A1 were higher in the granulosa and interstitial cells in the PCOS group. Conclusion: the results indicate that the interstitial cells are derived from the theca interna and that enzymatic changes occur in the theca interna and interstitial cells in ovaries of rats with PCOS, responsible for the high levels of androgens and estradiol.

[Morphology of the interstitial cells of rat polycystic ovaries: an experimental study]

PURPOSES

To evaluate the histomorphometry of ovarian interstitial cells, as well as the blood sex steroid concentrations of female rats with polycystic ovaries induced by continuous light.

METHODS

Twenty female rats were divided into two groups: Control Group - in the estrous phase (CtrlG), and a group of rats with polycystic ovaries induced by continuous illumination (POG). CtrlG animals were maintained on a light period from 07:00 a.m. to 07:00 p.m., and POG animals with continuous illumination (400 Lux) for 60 days. After this period all animals were anesthetized and blood was collected for the determination of serum estradiol (E2), progesterone (P4), and testosterone (T), followed by removal of the ovaries that were fixed in 10% formalin and processed for paraffin embedding. Five-µm histological sections were stained with hematoxylin and eosin and used for histomorphometric analysis. Morphological analyses, cyst count, determination of concentration and of the nuclear volume of interstitial cells were performed with the aid of a light microscope adapted to a high resolution camera (AxioCam), whose images were transmitted to and analyzed by the computer using AxioVision Rel 4.8 software (Carl Zeiss). Data were analyzed statistically by the Student's t-test (p<0.05).

RESULTS

Morphological analysis showed the presence of ovarian cysts in POG animals and corpora lutea in CtrlG animals, as well as evidence of the origin of interstitial cells from the internal theca of these cysts. POG animals presented increased serum estradiol levels (pg/mL) compared to CtrlG animals (POG=124.9 ± 4.2>CtrlG=73.2 ± 6.5, p<0.05), the same occurring with testosterone levels (pg/mL) (POG=116.9 ± 4.6>CtrlG=80.6 ± 3.9, p<0.05). However, progesterone levels (ng/mL) were higher in CtrlG than in POG animals (CtrlG=16.3 ± 2.0>POG=4.2 ± 1.5, p<0.05). Morphometry showed a significant increase in nuclear volume in POG animals (POG=102.1 ± 5.2>CtrlG=63.6 ± 16.5, p<0.05), as well as in the area occupied (%) by interstitial cells (POG=24.4 ± 6.9>CtrlG=6.9 ± 3.2, p<0.05) compared to CtrlG animals.

CONCLUSION

The interstitial cells of the rat polycystic ovary probably originate from ovarian cysts due to the degeneration of granulosa cells and differentiation of the internal theca cells. The elevations of serum testosterone and estradiol were probably due to the significant increase in cell activity and in the area occupied by interstitial cells.