Kisspeptin (Kp-10) inhibits in vitro osteogenic differentiation of multipotent mesenchymal stromal cells extracted from the bone marrow of adult rats

Kisspeptin (Kp-10) is a neuropeptide that binds to GPR54 receptors, exerting several functions mainly in the nervous and reproductive systems of the body. However, its effects and mechanisms of action on the skeletal system remain poorly understood. This study evaluated the effects of different concentrations of Kp-10 on in vitro osteogenic differentiation of multipotent mesenchymal stromal cells (MSCs) extracted from the bone marrow (BM) of adult Wistar rats. Two-month-old female rats were euthanized to extract BM from long bones to obtain MSCs. Four experimental groups were established in vitro: a control and Kp-10 at concentrations of 0.01, 0.05 and, 0.1 µg/mL. After induction of osteogenic differentiation, cell viability was evaluated using the 3-(4,5-dimethylthiazol-2-yl)- 2,5-diphenyl tetrazolium bromide (MTT) assay, alkaline phosphatase activity, collagen synthesis, percentage of area covered by MSCs/field and mineralized nodules/field, and immunocytochemistry of the GPR54 receptor tests. Furthermore, evaluation of gene transcripts for type I collagen, Runx-2, Bmp-2, bone sialoprotein, osteocalcin and osteopontin was performed using real-time RT-qPCR. It was observed that MSCs expressed GPR54 receptor to which Kp-10 binds during osteogenic differentiation, promoting a negative effect on osteogenic differentiation. This effect was observed at all the Kp-10 concentrations in a concentration-dependent manner, characterized by a decrease in the activity of alkaline phosphatase, collagen synthesis, mineralized nodules, and decreased expression of gene transcripts for type I collagen, osteocalcin, osteopontin, and Runx-2. Thus, Kp-10 inhibits in vitro osteogenic differentiation of MSCs extracted from the BM of adult Wistar rats.

Effect of the addition of different concentrations of Solanum glaucophyllum desf. extract on chondrocyte cultures from the growth cartilage of newborn rats

Solanum glaucophyllum Desf. Is a calcinogenic plant responsible for enzootic calcinosis that affects ruminants and causes alterations in bone and cartilaginous tissues, among others. It is believed that changes in cartilage tissue, with reduced bone growth, are due to hypercalcitoninism, caused by excess vitamin D. However, we hypothesized that S. glaucophyllum Desf. Can act directly on chondrocytes and therefore, chondrocyte cultures from the epiphysis of the long bones of newborn rats were used as a model to elucidate the direct effects of S. glaucophyllum Desf. On bone growth. Plant samples were collected from Cañuelas, Argentina. An aliquot of the plant extract was used to quantify vitamin D (1,25(OH)2D3). The effects of the three concentrations of the plant extract were tested in cultures of chondrocytes extracted from the epiphyses of the long bones of 32 three-day-old Wistar rats. A control group (without extract treatment), and three groups treated with different concentrations of plant extract were formed: group 1 (100 μL/L); group 2 (1 mL/L), and group 3 (5 mL/L), containing respectively 1 × 10^-9 M, 1 × 10^-8 M, and 5 × 10^-8 M of 1,25(OH)2D3. After 7, 14, and 21 days of culture, MTT assay for cell viability, alkaline phosphatase activity, and quantification of the percentage of areas with glycosaminoglycans (GAG) stained with periodic acid-Schiff (PAS) were performed. On day 7, all chondrocytes in group 3, that is, those with the highest concentration of plant extract, died. On days 14 and 21, groups 1 and 2 showed a significant reduction in chondrocyte viability compared to the control. At 7, 14, and 21 days, groups 1 and 2 showed significantly lower alkaline phosphatase activity than the control. On day 21, group 2 showed a significant reduction in areas with PAS + GAGs. There were no significant differences between the groups in the expression of gene transcripts for Sox9, Col2, ColX, and aggrecan. The S. glaucophyllum Desf. Extract directly affected growing rat chondrocytes by reducing viability, alkaline phosphatase activity, and GAG synthesis without altering the expression of gene transcripts for Sox9, Col2, ColX, and aggrecan, which may be one of the mechanisms by which there is a reduction in bone growth in animals intoxicated by the plant.

Ethanol Alters Phenotype and Synthesis Activity of Rat Neonatal Articular Chondrocytes Grown in 2- and 3-Dimensional Culture

OBJECTIVE

We sought to evaluate the effect of different concentrations of ethanol on phenotype and activity of articular chondrocyte synthesis of neonatal rats in 2-dimensional (2D) and 3-dimensional (3D) culture.

METHODS

Chondrocytes were cultured in chondrogenic medium with different concentrations of ethanol: 0.0% v/v (control); 0.05% v/v (8.6 mM); 0.25% v/v (42.9 mM), and 0.5% v/v (85.7 mM). Chondrocytes under 2D culture were subjected to MTT assay, while chondrocytes under 3D culture were processed for paraffin inclusion and stained by periodic acid Schiff (PAS) to evaluate mean chondrocyte diameter and percentages of cells, nucleus, cytoplasm, well-differentiated matrix, and PAS+ areas. The expression of gene transcripts for aggrecan, Sox9, and type II collagen was evaluated by real-time quantitative polymerase chain reaction.

RESULTS

There was no difference between groups by the MTT assay. PAS staining revealed that chondrocytes treated with 0.5% v/v ethanol had higher percentages of cytoplasm and nuclear areas, but with a reduction in PAS+ matrix area. The mean diameter of chondrocytes was similar between groups. The expression of aggrecan in the group treated with 0.5% v/v ethanol was lower in comparison to that in the control. In the groups treated with 0.25% v/v and 0.5% v/v ethanol, the percentage of differentiated cartilage was lower in comparison with that in the control. The group treated with 0.05% v/v ethanol was similar to the control in all parameters.

CONCLUSIONS

Ethanol acted directly on in vitro cultured articular chondrocytes of newborn rats, altering the chondrocyte phenotype and its synthesis activity, and these effects were dose dependent.

Differentiation of canine adipose mesenchymal stem cells into insulin-producing cells: comparison of different culture medium compositions

The aim of this study was to differentiate canine adipose-derived mesenchymal stem cells (ADMSCs) into insulin-producing cells by using culture media with different compositions to determine the most efficient media. Stem cells isolated from the fat tissues close to the bitch uterus were distributed into 6 groups: (1) Dulbecco's modified Eagle medium (DMEM)-high glucose (HG), β-mercaptoethanol, and nicotinamide; (2) DMEM-HG, β-mercaptoethanol, nicotinamide, and exendin-4; (3) DMEM-HG, β-mercaptoethanol, nicotinamide, exendin-4, B27, nonessential amino acids, and l-glutamine; (4) DMEM-HG, β-mercaptoethanol, and nicotinamide (for the initial 8-d period), and DMEM-HG, β-mercaptoethanol, nicotinamide, exendin-4, B27, nonessential amino acids, l-glutamine, and basic fibroblast growth factor (for the remaining 8-d period); (5) DMEM-HG and fetal bovine serum; and (6) DMEM-low glucose and fetal bovine serum (standard control group). Adipose-derived mesenchymal stem cells from groups 1 to 5 gradually became round in shape and gathered in clusters. These changes differed between the groups. In group 3, the cell clusters were apparently more in numbers and gathered as bigger aggregates. Dithizone staining showed that groups 3 and 4 were similar in terms of the mean area of each aggregate stained for insulin. However, only in group 4, the number of insulin aggregates and the total area of aggregates stained were significantly bigger than in the other groups. The mRNA expression of PDX1, BETA2, MafA, and Insulin were also confirmed in all the groups. We conclude that by manipulating the composition of the culture medium it is possible to induce canine ADMSCs into insulin-producing cells, and the 2-staged protocol that was used promoted the best differentiation.

The Solanum glaucophyllum Desf. extract reduces mineralized matrix synthesis in osteogenically differentiated rat mesenchymal stem cells in vitro

The Solanum glaucophyllum Desf. has been used to treat and prevent diseases in human and veterinary medicine. On the other hand, plant poisoning causes several bone diseases, among them osteoporosis, which is characterized by osteoblastic hypoplasia. Because the osteoblast is a cell derived from the differentiation of mesenchymal stem cells (MSCs) from bone marrow, the hypothesis is that the plant reduces the osteogenic differentiation of MSCs. The objective of this study was to evaluate the effects of S. glaucophyllum Desf. extract on MSCs cultured in osteogenic differentiation medium. We determined by liquid chromatography that 1 ml of plant extract contained 3.8 μl of 1,25(OH)₂ D₃ (calcitriol). Four groups of MSCs cultivated in osteogenic medium were evaluated as follows: (a) treated with 100 μl of extract/L containing 0.4 μg/L of calcitriol; (b) treated with 1 ml of extract/L containing 4 μg/L of calcitriol; (c) treated with 5 ml of extract/L containing 20 μg/L of calcitriol; and (d) a control group without extract. We performed alkaline phosphatase activity assay, analysis of MTT conversion to formazan, and evaluated the percentage of cells, and number and diameter of mineralization nodules. The expression of gene transcripts for osteopontin, bone sialoprotein and BMP-2 was analysed by RT-qPCR. After 21 days, there was a significant reduction in MTT conversion to formazan in treated groups, of the cellularity in the group with 5 ml of extract/L, and in the number and size of mineralization nodules in the groups treated with 1 and 5 ml of extract/L. The 5 ml extract/L concentration also reduced transcript expression of osteopontin. It is concluded that S. glaucophyllum Desf. at concentrations of 1 and 5 ml extract/L reduced mineralized matrix synthesis in MSCs cultivated in osteogenic differentiation medium, which suggests that this is one of the mechanisms by which osteoporosis occurs in intoxicated animals.

Didelphis albiventris: an overview of unprecedented transcriptome sequencing of the white-eared opossum

BACKGROUND

The white-eared opossum (Didelphis albiventris) is widely distributed throughout Brazil and South America. It has been used as an animal model for studying different scientific questions ranging from the restoration of degraded green areas to medical aspects of Chagas disease, leishmaniasis and resistance against snake venom. As a marsupial, D. albiventris can also contribute to the understanding of the molecular mechanisms that govern the different stages of organogenesis. Opossum joeys are born after only 13 days, and the final stages of organogenesis occur when the neonates are inside the pouch, depending on lactation. As neither the genome of this opossum species nor its transcriptome has been completely sequenced, the use of D. albiventris as an animal model is limited. In this work, we sequenced the D. albiventris transcriptome by RNA-seq to obtain the first catalogue of differentially expressed (DE) genes and gene ontology (GO) annotations during the neonatal stages of marsupial development.

RESULTS

The D. albiventris transcriptome was obtained from whole neonates harvested at birth (P0), at 5 days of age (P5) and at 10 days of age (P10). The de novo assembly of these transcripts generated 85,338 transcripts. Approximately 30% of these transcripts could be mapped against the amino acid sequences of M. domestica, the evolutionarily closest relative of D. albiventris to be sequenced thus far. Among the expressed transcripts, 2077 were found to be DE between P0 and P5, 13,780 between P0 and P10, and 1453 between P5 and P10. The enriched GO terms were mainly related to the immune system, blood tissue development and differentiation, vision, hearing, digestion, the CNS and limb development.

CONCLUSIONS

The elucidation of opossum transcriptomes provides an out-group for better understanding the distinct characteristics associated with the evolution of mammalian species. This study provides the first transcriptome sequences and catalogue of genes for a marsupial species at different neonatal stages, allowing the study of the mechanisms involved in organogenesis.

Rat mesenchymal stem cell cultures as a model to elucidate the cellular and molecular pathogenesis of bone metaplasia induced by Solanum glaucophyllum intoxication

The hypothesis of this experiment is that mesenchymal stem cells (MSCs) are involved in the genesis of the bone metaplasia caused by Solanum glaucophyllum intoxication. We determined using liquid chromatography that 1 mL of plant extract contained 3.8 μl of 1,25(OH)₂D₃. The ability of 100 μL, 1 mL and 5 mL of extract/L, containing 1 nM (0.4 μg/L), 10 nM (4 μg/L) and 50 nM (20 μg/L) of 1,25(OH)₂D_3, respectively, in inducing the osteogenic differentiation in bone marrow MSCs from rats was tested. At the concentrations of 1 and 5 mL of extract/L of culture medium without osteogenesis-inducing factors, the plant extract induced the osteogenic differentiation of the MSCs, as was evidenced by the greater synthesis of mineralized matrix. At the higher concentration (5 mL of extract/L), an increase in the relative expression of BMP-2 gene was observed. It was concluded that rat bone marrow MSC culture is a good model for studying the effects of the S. glaucophyllum extract on the osteogenic differentiation of undifferentiated cells. Also, S. glaucophyllum extracts containing 10 nM (4 μg/L) and 50 nM (20 μg/L) of 1,25(OH)₂D₃ induce the osteogenic differentiation of MSCs, suggesting that this is one of the mechanisms by which S. glaucophyllum causes bone metaplasia.

Nonlinear effects of caffeine on the viability, synthesis and gene expression of chondrocytes from the offspring of rats treated during pregnancy

OBJECTIVE

Evaluate the effects of doses of caffeine administered to pregnant rats on the articular cartilage chondrocytes of their offspring.

METHODS

Twenty-four adult Wistar rats were randomly assigned to four groups, with one control group and three groups being treated with caffeine at doses of 25, 50 and 100 mg/kg throughout pregnancy. At birth, three offspring/females were euthanized so that the chondrocytes could be extracted. At 7, 14 and 21 days of culture, the chondrocytes were subjected to the MTT cell viability assay and an evaluation of their alkaline phosphatase activity and collagen synthesis. Chondrocytes were also stained by Hematoxylin-eosin, PAS, Safranin-O and Alcian Blue. The Sox-9, Runx-2, aggrecan, collagen-II and alkaline phosphatase gene transcript levels were also evaluated. Mean comparisons were performed by the Student-Newman-Keuls test.

RESULTS

Chondrocyte cultures from the 25 mg/kg group had the lowest results, as chondrocytes from this group had reduced viability, percentage of cells, alkaline phosphatase activity and collagen and chondrogenic matrix synthesis. A reduced expression of Sox-9, alkaline phosphatase and collagen-II was also detected in the 25 mg/kg group. Chondrocyte cultures of the group treated with 50 mg/kg caffeine showed reduced collagen synthesis and Sox-9 expression. The caffeine dose of 100 mg/kg also reduced collagen and Sox-9 and alkaline phosphatase expression.

CONCLUSION

Caffeine administered to pregnant rats negatively alters the articular cartilage chondrocytes of their offspring, reducing the synthesis of collagen and Sox-9 expression regardless of the dose. This study also concluded that the effects of caffeine are not linear or dose-dependent.

Effects of excess maternal thyroxin on the bones of rat offspring from birth to the post-weaning period

Objective To evaluate, in rat offspring, bone changes induced by excess maternal thyroxin during pregnancy and lactation, and to assess the reversibility of these changes after weaning. Material and methods Twenty Wistar rats were distributed in two groups, hyperthyroid and control, that were treated daily with L-thyroxin (50 mcg/animal) and placebo, respectively. The treatment was initiated seven days before mating and continued throughout pregnancy and lactation. From every female of each of the two groups, two offspring were euthanized after birth, two at 21 days of age (weaning), and two at 42 days of age (21 days after weaning). In newborns, the length of pelvic and thoracic limbs were measured, and in the other animals, the length and width of the femur and humerus were measured. Bones were dissected, decalcified, embedded in paraffin, and analyzed histomorphometrically. Results Excess maternal thyroxin significantly reduced the length of the pelvic limb in neonates. In 21-day-old individuals, excess maternal thyroxine reduced the length and the width of the femur and the humerus. It also increased thickness of the epiphyseal plate and the percentage of trabecular bone tissue. In 42-day-old individuals, there were no significant differences between groups in relation to the parameters evaluated in the previous periods. Conclusion Excess maternal thyroxine reduced growth in suckling rats both at birth and at weaning, and it also increased the percentage of trabecular bone tissue in 21-day-old animals. These changes, however, were reversible at 42 days, i.e., 21 days after weaning. Arch Endocrinol Metab. 2016;60(2):130-7.

Inhibition of the osteogenic differentiation of mesenchymal stem cells derived from the offspring of rats treated with caffeine during pregnancy and lactation

Caffeine is an alkaloid that is widely consumed due to its presence in drugs, coffee, tea, and chocolate. This compound passes to offspring through the placenta and milk; can cause teratogenic mutations; and reduces the formation, growth, and mass of bone. Because mesenchymal stem cells (MSCs) are responsible for generating the entire skeleton, we hypothesized that these cells are targets of caffeine. This study evaluated the osteogenic differentiation of MSCs derived from the offspring of rats treated with caffeine during pregnancy and lactation. Twenty-four adult Wistar rats were randomly divided into four groups, including one control group and three experimental groups treated with 25, 50, or 100 mg/kg of caffeine. At weaning, three 21-day-old pups from each dam in each group were euthanized for extraction of bone marrow cells for in vitro tests. Caffeine doses of 50 and 100 mg/kg significantly reduced the activity of alkaline phosphatase at 7, 14, and 21 days and the expression of collagen I at 21 days. However, the expression of gene transcripts for alkaline phosphatase, Runx-2, and bone sialoprotein, as well as the synthesis of mineralization nodules, decreased significantly in all groups treated with caffeine. The expression of osteocalcin was significantly reduced only in the group treated with 50 mg/kg caffeine. The caffeine that passes from the mother to the offspring during pregnancy and lactation reduces the osteogenic differentiation of MSCs. We propose that this reduction in the osteogenic potential of MSCs may be involved in the pathogenesis of osteopenia resulting from caffeine consumption.

Osteogenic potential of osteoblasts from neonatal rats born to mothers treated with caffeine throughout pregnancy

BACKGROUND

Caffeine is an active alkaloid that can cause damage to bones in formation during prenatal life into adulthood. This compound can pass across the placenta and into the mother's milk, causing a reduction in bone formation, growth and mass. The objective of this study was to examine the osteogenic potential of osteoblasts extracted from neonatal rats born to mothers treated with caffeine throughout pregnancy.

METHODS

Twenty-four adult Wistar rats were randomly divided into four groups, consisting of one control group and three groups that were treated with 25, 50, or 100 mg/kg of caffeine by an oral-gastric probe throughout the duration of the experimental period (pregnancy). At birth, three puppies from each dam in each group were euthanized, and osteoblasts were extracted from the calvaria of these pups for in vitro testing.

RESULTS

The osteoblasts extracted from the pups of rats that received 50 mg/kg caffeine during pregnancy exhibited increased expression of osteocalcin, osteopontin, sialoprotein, runx-2, alkaline phosphatase and type I collagen transcripts, resulting in increased synthesis of mineralization nodules.

CONCLUSIONS

Neonates from rats treated with 50 mg/kg caffeine during pregnancy contained osteoblasts with a higher osteogenic potential characterized by increased expression of osteocalcin, osteopontin, sialoprotein, runx-2, alkaline phosphatase and type I collagen and increased synthesis of mineralization nodules.

In vitro effects of caffeine in growth cartilage of rats

OBJECTIVE

To evaluate the in vitro effetcs of caffeine on proliferation, apoptosis a nd gene transcripts expression of chondrogenic differentiation in growth cartilage.

METHODS

THE CARTILAGINOUS EPIPHYSES OF FEMURS OF NEWBORN RATS, WHICH WERE DIVIDED INTO TWO SUBGROUPS: treated with caffeine and control group, both observed over the time periods of 0, 7, 14 and 21 days. The cartilaginous epiphyses of femurs of each subgroup and each time span were subjected to histomorphometric, immunohistochemical analysis, Tunel technique and RT-PCR in real time.

RESULTS

The decrease in proliferative activity and the increase of apoptotic chondroblasts at 21 days were found regardless of the subgroup. However, the decrease in cell proliferation caused by caffeine was lower than in the control group and significantly increased the expression of gene transcripts for chondrogenic differentiation, represented by Sox-9 and Runx-2. However, the in vitro culture with caffeine revealed antagonistic effects: despite the positive effect on chondroblasts proliferation and differentiation, caffeine increased apoptosis, characterized by increased expression of caspase 3 and of the number of cells undergoing apoptosis (p<0.05).

CONCLUSION

Caffeine presents antagonistic effects in vitro on growth cartilage, increasing the proliferation, differentiation and cell apoptosis. Experimental Study .

Role of autologous mesenchymal stem cells associated with platelet-rich plasma on healing of cutaneous wounds in diabetic mice

BACKGROUND

Chronic cutaneous lesions affect 15% of human patients with diabetes, and the associated risk of limb amputations is 15-46 times greater than that of people with normal glycaemia. It is estimated that half of these limb amputations could be avoided by opportune treatment with somatic stem cells or platelet-rich plasma (PRP).

METHODS

We evaluated the effects of autologous transplant of mesenchymal stem cells (MSCs) with or without combination with autologous PRP in the re-epithelialization of cutaneous lesions induced in diabetic mice.

RESULTS

Animals treated with MSCs alone showed a similar level of re-epithelialization of cutaneous lesions to those treated with MSC plus PRP, and no significant difference was found between the two treatments.

CONCLUSION

Both treatments gave better results than daily cleaning of the cutaneous lesions with saline or covering of the lesions with semipermeable adherent bandage.