Glycyrrhizic acid attenuated lipid peroxidation induced by titanium dioxide nanoparticles in rat liver

OBJECTIVE

to investigate the hepatoprotective effect of glycyrrhizic acid (GA) against hepatic injury induced by titanium dioxide nanoparticles (NTiO2) in rats.

BACKGROUND

Many recent studies demonstrate that most nanoparticles (NPs) have an adverse or toxic action on liver.

METHODS

NTiO2- intoxicated rats received 300 mg/kg of NTiO2 for 14 days by gavage method. Protection group was pretreated with 10 mg/kg of GA for 7 days before NTiO2 administration. Alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP) were detected as biomarkers in the blood to indicate hepatic injury. Product of lipid peroxidation (MDA), superoxide dismutase (SOD) and glutathione peroxidase (GPx) were evaluated for oxidative stress in hepatic injury. Light microscopy for histopathological studies was also done.

RESULTS

Administration of NTiO2 induced a significant elevation in plasma AST, ALT and ALP. In the liver, NTiO2 increased the oxidative stress through the increase in lipid peroxidation and decrease in SOD and GPx enzymes. Pretreatment of GA significantly decreased ALT, AST and ALP, attenuated the histopathology of hepatic injury, ameliorated oxidative stress in hepatic tissue, and increased the activities of SOD and GPx.

CONCLUSION

These findings indicate that GA effectively protects against NTiO2-induced hepatotoxicity in rats and might be clinically useful (Fig. 4, Ref. 47). Text in PDF www.elis.sk.

Protective effect of beta-carotene against titanium dioxide nanoparticles induced apoptosis in mouse testicular tissue

In this study, the effects of beta-carotene (BC) on testicular germ cell apoptosis arising from titanium dioxide nanoparticles (NTiO2 ) have been evaluated. In NTiO2 -treated mice, expression of apoptotic related genes including Bid, FasL, caspase-3 and p38MAPK was significantly increased. Measurement apoptosis using TUNEL method showed significant increase in apoptotic index of germ cells in NTiO2 -treated mice (P < 0.05). TUNEL assessments showed that the increase of apoptotic index of testicular germ cells in NTiO2 -treated mice was reversed by BC. Beta-carotene pre-treatment could also effectively attenuate the expression of apoptotic related genes. The application of BC may serve as a beneficial medication to protect germ cells against apoptosis induced by nanoparticles and be helpful for male fertility.

Effect of bone morphogenetic protein-2 on normal and osteoarthritic human articular chondrocytes

In this study, we investigated whether Bone Morphogenetic Protein-2 (BMP-2) could modulate dedifferentiation, apoptosis and proliferation capacity in the normal and OA cultured chondrocytes. The articular chondrocytes from normal (n = 4) and OA (n = 4) cartilages were harvested separately. The chondrocytes were cultured in monolayer in the presence of 100 ng mL(-1) BMP-2 and 1% FBS as a test group and 1% FBS alone as a control group. Then, the chondrocytes were harvested and assessed for morphology with invert microscopy, proliferation by using MTT-assay and apoptosis with caspase-3 immunocytochemistry. The results indicated that the normal and the most OA chondrocytes showed round and polygonal appearance with chondrocyte-like morphology in BMP-2 treated groups after 6 days. The MTT proliferation test didn't show significant difference between test and control groups. The OA cells showed proliferation rate higher than the normal cells and significant difference in the presence of BMP-2 was observed (p<0.05). Positive immunostaining of caspase-3 in test and control groups was 1 and 20% in normal and 30 and 43% in OA groups, respectively. The percentage of apoptosis was reduced in the presence of BMP-2. In conclusion, it appears that BMP-2 involves in suppression of dedifferentiation and apoptosis processes of cultured human chondrocytes.

Protective effect of minocycline on dexamethasone induced testicular germ cell apoptosis in mice

BACKGROUND

Apoptosis involves in testicular germ cell loss in animals and humans, and plays an important role in male fertility. Previous studies have reported neuroprotective and antiapoptotic effects of minocycline.

AIM

In this study the protective effect of Minocycline on testicular germ cell apoptosis arising from dexamethasone (Dex) has been evaluated. Dex is a widely used as a glucocorticoid (GC) agent that its apoptotic effect has been shown.

MATERIALS AND METHODS

Experimental groups of 8 male mice received one of the following treatments daily for 7 days: 100 mg/kg Minocycline, 7 mg/kg Dex and 7 mg/kg Dex +100 mg/kg Minocycline. Control group was treated with 0.5 ml saline given orally for a week. Then the mice were sacrificed, and their testes processed for assessment of germ cell apoptosis (TUNEL method), the quality of spermatogenesis (Johnsen score system) and testicular sperm counts.

RESULTS

Germ cell apoptosis were significantly increased in Dex treated mice compared with control (P < 0.01). Spermatogenesis and the number of sperms head were significantly reduced in Dex treated mice compared with those of the control group (P < 0.01). Treatment with Dex and Minocycline resulted in an inhibition effect on germ cell apoptosis and a significant increase in the Johnsen score and the number of head sperm compared with Dex treated mice (P < 0.05).

CONCLUSION

The application of Minocycline may serve as a beneficial medication to protect germ cells against apoptosis.

Dexamethasone effects on fas ligand expression in mouse testicular germ cells

The aim of this study is to investigate the effect of Dex, a widely used GC, on apoptosis and expression of FasL protein in the mouse testicular germ cells. The effects of dexamethasone (Dex) on expression of Fas ligand (FasL), an important proapoptotic protein, in the mouse testicular germ cells were investigated. Six groups, each of 8 male NMRI mice were chosen for the experiment. Experimental groups received one of the following treatments daily for 7 days: 4, 7 and 10 mg kg(-1) Dex. Control groups were treated with equivalent volumes of saline. Experimental and control animals were sacrificed 24 h after the last injection. Immunohistochemical procedure was used to evaluation of FasL expression and the deoxyuridine nick-end labeling (TUNEL) was applied to assessment of the apoptotic germ cells. FasL expression of testicular germ cells were significantly increased in 10 mg kg(-1) Dex treated mice (p < 0.05), particularly at stages VII-VIII of spermatogenic cycle. Apoptotic indexes (AIs) of germ cells were significantly increased in 7 and 10 mg kg(-1) Dex treated mice.

Mechanical responses and integrin associated protein expression by human ankle chondrocytes

Metabolic, biochemical and biomechanical differences between ankle and knee joint cartilage and chondrocytes including resistance to the effects of catabolic cytokines and fibronectin fragments may be relevant to differences in prevalence of OA in these joints. Although there is increasing information available on how chondrocytes from knee and hip joint cartilage recognise and respond to mechanical stimuli, knowledge of mechanotransduction in ankle joint chondrocytes is limited. This study was undertaken to (i) establish whether the response of normal ankle joint derived chondrocytes to mechanical stimulation in vitro was similar to that of normal and osteoarthritic knee joint derived chondrocytes and (ii) to investigate whether these chondrocytes showed differences in expression of integrin associated regulatory and signalling molecules. Unlike normal knee joint chondrocytes, ankle joint chondrocytes did not show an increase in relative levels of aggrecan mRNA when mechanically stimulated. No obvious change in protein tyrosine phosphorylation was seen in ankle chondrocytes subsequent to mechanical stimulation but these cells expressed elevated levels of tyrosine phosphorylated proteins at rest when compared to normal knee joint chondrocytes. Ankle joint chondrocytes showed an increase in protein kinase B phosphorylation following 1 min 0.33 Hz stimulation which was inhibited by the presence of antibodies to alpha5beta1 integrin. Ankle joint chondrocytes appeared to show significant differences in levels of the integrin-associated proteins CD98, CD147 and galectin 3, PKCgamma and differences in responses to glutamate were seen. Chondrocytes from ankle and knee joint cartilage respond differently to 0.33 Hz mechanical stimulation. This may be related to modified integrin-dependent mechanotransduction as a result of changes in expression of integrin regulatory molecules such as CD98 or differential expression and function of downstream components of the mechanotransduction pathway such as PKC or NMDA receptors.