[ effect of flavonoid naringenin on contractile response of thoracic aorta isolated from diabetic rats]

Background and Aims: Considering increasing incidence of cardiovascular disorders in diabetes mellitus and some evidence on antioxidant and antidiabetic potentials of naringenin, this study was conducted to evaluate the beneficial effects of 6-week administration of naringenin on contractile reactivity of isolated thoracic aorta in diabetic rats

Methods: Male Wistar rats were divided into control, naringenin-treated control, diabetic and glibenclamide-treated, and naringenin-treated diabetic groups. For induction of diabetes, streptozotcin [STZ] was administered [60 mg/Kg]. Naringenin [10 mg/kg] was administered i.p. one week after diabetes induction in every other day intervals for 6 weeks. Serum glucose level was measured before naringeninadministration and at 6th week. Finally, contractile reactivity of thoracic aortic rings to KCl and phenylephrine [PE] was cumulatively determined

Results: Serum glucose level at week 6 showed a significant decrease in naringenin-treated diabetic group compared to diabetics [P<0.01]. In addition, naringenin-treated diabetic group showed a significantly lower contraction to PE [P<0.05] as compared to diabetic group and such significant reduction was also observed for KCl [P<0.05]. Meanwhile, there was also a significant difference between control and naringenin-treated control groups regarding their contractile reactivity to PE [P<0.05]

Conclusion: Subchronic administration of naringenin for 6 weeks could exert an anti-hyperglycemic effect and lowers contractile responsiveness of thoracic aorta rings to KCl and phenylephrine

[Study of expression level of cartilage genes in rat articular chondrocyte monolayer and 3D cultures using real time PCR]

To compare the expression level of certain genes related to cartilage and non-cartilage tissues at monolayer and alginate cultures derived from rat articular cartilage. Articular cartilage was harvested from knee joints of 10 male rats and was digested using enzymatic solution consisting of 0.2% collagenase I and 0.1% pronase. Released chondrocyte were then plated in 25-cm2 culture flasks and expanded. For alginate culture, about 5x10[6] passaged-5 cells were mixed with 1 ml alginate solution and cultivated as small beads for a period of two months. During the culture, the expression of Sox9, collagen II, I and aggrecan genes were quantified by real time PCR and compared with the gene expressions at monolayer cultures. Furthermore, the cell morphology, in this study, was observed using either conventional or inverted light microscopy. The cells at monolayer cultures were observed as spindly shaped cells, while within alginate, chondrocytes tended to be morphologically spherical cells. Real time PCR analysis indicated that at monolayer cultures, the expression of Sox9, collagen II and aggrecan were significantly down-regulated while the expression of collagen I was largely up-regulated. In contrast to monolayer cultures, the expression levels of sox 9, collagen II and aggrecan, at alginate cultures, tended to be statistically high while collagen I was observed to be expressed at negligible level. All these differences were statistically significant [p <0.05]. While at chondrocyte monolayer cultures, the cartilage-specific gene expressions appeared to be significantly down-regulated, alginate culture tended to stimulate the cells to express the genes in statistically high levels

Equine marrow-derived mesenchymal stem cells: isolation, differentiation and culture optimization

Most studies regarding the marrow-derived equine mesenchymal stem cells [MSCs] have mainly focused on the cell transplantation without considering the capacity of differentiation and in vitro requirements of the cells. These concerns were investigated in the present study. Equine MSCs were isolated from the sternal marrow aspirates and expanded through two successive subcultures. Passage-2 equine MSC cultures were then treated with appropriate supplements in order to examine the cell osteogenic, chondrogenic and adipogenic differentiation potential. Furthermore, the culture of the cells was investigated in terms of the optimal concentration of fetal bovine serum [FBS] and the initial cell-seeding density. Additionally, a growth curve was plotted for the cells to study their growth characteristics. According to our findings, equine MSCs were easily generated specialized bone, cartilage and adipose cell lineages as confirmed by specific staining and RT-PCR analysis. Moreover, the cells exhibited rapid expansion when being cultivated in the medium with 15% FBS at 100 cells/cm[2]. Growth curves indicated that these cells rapidly entered the log phase after a brief lag [adaptation] period. In summary, marrow-derived equine MSCs possess tripotent differentiation capacity and rapid growth rate in the appropriate culture conditions

[Study of differentiation potential of the dedifferentiated chondrocytes from rat articular cartilage into skeletal cell lineages]

Dedifferentiation of the chondrocyte from rat articular cartilage with multiple subcultures and study of the redifferentiation potential of the cells into bone, cartilage and fat cell lineages. In this experimental study, chondrocytes from rat articular cartilage were isolated and expanded through several successive subcultures during which the expression levels of cartilage-specific genes including aggreacan and type II collagen were measured by using real-time PCR to determine the cell dedifferentiation [the time in which cartilage genes ceased their expression]. Furthermore, during the culture period, the chondrocyte was examined morphologically by scanning electron microscopy [SEM]. At the end, the dedifferentiated cells were subjected to osteogenic, adipogenic and chondrogenic culture condition to investigate whether or not they are able to redifferentaite into specialized progenies. Differentiation state was examined by specific staining and RT-PCR analysis. Based on the findings by real time PCR, the expression levels of the both studied genes were high at passage 2 and dramatically decreased at passage 4. Aggreacan expression ceased at passage 10 and collagen II stopped expressing at passage 6. SEM images indicated the flattened morphology of the cells at early passages and the fibroblastic appearance at late passages. Differentiation examination revealed that the dedifferentiated cells were readily differentiated into bone, adipose and cartilage cell lineages. Considering all aspects together, this concluded that articular chondrocyte gradually lost their differentiated state during the long-term culture and changed into multipotent cells capable of differentiating into skeletal cell lineages