Exposure to cadmium during gestation and lactation affects development and function of Leydig cells in male offspring.

Toxic effects of maternal exposure to Cadmium (Cd) on Leydig cells of male offspring arises much concern recently, but its toxic effects on the development of Leydig cells and androgen synthesis have not been elucidated. In this study, female rats were exposed to Cd during gestation and lactation, and the development of Leydig cells in the first filial-generation (F1) male rats was investigated. The steroidogenic signaling pathway and biomarkers related to the development of Leydig cells were detected to disclose how maternal Cd-exposure caused reproductive damage. F1 male rats with maternal Cd-exposure gained a low relative weight of testis and declined levels of steroid hormones. Maternal Cd-exposure interrupted the development of Leydig cells with high expression of SRD5α and cell morphology of immature Leydig cells in adulthood, inhibited the activation of cyclic adenosine monophosphate/ protein kinase A signaling pathway and down-regulated the steroidogenic enzymes. These results would help to disclose the origin of male sexual dysfunction in the developmental stages of Leydig cells.

Recognition of Volleyball Player's Arm Motion Trajectory and Muscle Injury Mechanism Analysis Based upon Neural Network Model.

At present, in sports training for volleyball, it still mainly depends on the personal experience of the coach. Training costs are high, and the quality is difficult to maintain stable. Even with the introduction of training assistance software, it is often necessary to manually enter complex data, and the research samples are mostly single individuals. Serving is one of the basic and important technical movements of volleyball, and its standardization is of great significance to the stable performance of the scene. This article proposes an analysis of the volleyball player's arm trajectory based on the background of human posture recognition and analysis, based on the neural network model. The changes in the angles of the shoulders, elbows, and wrist when serving the ball reflect the different trajectories of the arm. Experiments show that the height of the throwing arm from the ground accounts for 98% of the height. The horizontal angle of the throwing arm at the moment the ball leaves the hand is positively correlated with the throwing time and height, and the reasonable trajectory has an impact on the stability of the throwing ball. The closer the trajectory of the tossing arm is to the vertical, the more stable the tossing is.

[Voltage-activated potassium channel blockers inhibit anisodamine-induced relaxation of rabbit aortic smooth muscles precontracted with noradrenaline].

Anisodamine, which is originally extracted from scopolia tangutica and is currently produced in China, is a tropane alkaloid and a muscarinic cholinoceptor blocker. Our previous study found that anisodamine did not alter high K(+)-evoked contraction of rabbit aortic rings using isometric tension recording methods, but could attenuate noradrenaline (NA)-, histamine- or 5-hydroxytryptamine-induced contraction in an endothelium-independent manner. Since the high K(+)-elicited depolarization non-selectively inhibits potassium channels in vascular smooth muscle cell (VSMC) membrane, the vasodilation effect of some potassium channel activators may be inhibited or abolished in high K(+) solution. We hypothesized that some potassium channels in VSMC membrane might play a role in the anisodamine-induced relaxation of blood vessels. The present experiment was designed to investigate whether potassium channel blockers inhibit anisodamine-induced relaxation of the rabbit isolated aortic rings. In a 8-min period, 1, 3 and 10 micromol/L of anisodamine, significantly relaxed the 0.01 micromol/L NA precontracted aortic ring by (19.1+/-3.1)%, (30.1+/-3.8)% and (38.3+/-4.2)%, respectively, compared with the controls [by (4.8+/-2.4)%, (5.1+/-1.8)% and (5.6+/-2.5)%, respectively] (P<0.01). 10 mmol/L of CsCl (a non-selective potassium channel blocker), 1 mmol/L of 4-aminopyridine [a selective voltage-activated potassium channel (K(V)) blocker], 10 mumol/L BaCl2 (a selective inwardly-rectifying potassium channel blocker), 10 micromol/L of glibenclamide (a selective ATP-sensitive potassium channel blocker), 3 micromol/L of charybdotoxin (a large- and intermediate-conductance Ca(2+)-activated potassium channels blocker) and 3 micromol/L of apamin (a selective small conductance Ca(2+)-activated potassium channel blocker) significantly increased the NA-induced contraction by (14.4+/-3.2)%, (16.3+/-5.8)%, (12.7+/-4.2)%, (13.6+/-2.0)%, (11.1+/-5.5)% and (13.4+/-4.3)%, respectively, compared with the control [by (5.6 +/-1.2)%] (P<0.01). In the presence of 10 and 30 mmol/L CsCl or 1 and 3 mmol/L 4-aminopyridine, anisodamine-induced relaxation of the 0.01 micromol/L NA contracted rabbit aortic rings [(28.8+/-3.0)% and (15.9+/-3.7)% or (29.7+/-3.9)% and (19.0+/-5.0)%] significantly deceased, compared with that in the absence of any potassium channel blocker [(38.3+/-4.2)% (P<0.01)] in a 8-min period. However, in the presence of 10, 30 micromol/L of BaCl2, 10, 30 micromol/L of glibenclamide, 3 micromol/L of charybdotoxin, or 3 micromol/L apamin, 10 micromol/L anisodamine-induced relaxation [(37.1+/-3.8)%, (36.2+/-4.7)%, (36.1+/-2.7)%, (35.6+/-3.3)%, (37.8+/-2.0)% and (39.3 +/-4.7) %, respectively] did not decrease, compared with the control [(38.3+/-4.2)%] (P>0.05). This study suggests that K(V) blockers inhibit anisodamine-induced relaxation of the rabbit aortic smooth muscle precontracted with NA and implies that the K(V) in VSMC membrane plays a role in anisodamine-induced relaxation of blood vessels.

Cytotoxic mechanism related to dihydrolipoamide dehydrogenase in Leydig cells exposed to heavy metals.

Heavy metals are common environmental toxicants with adverse effects on steroid biosynthesis. The importance of mitochondria has been recognized in cytotoxic mechanism of heavy metals on Leydig cells these years. But it is still poorly known. Our previous study reported that dihydrolipoamide dehydrogenase (DLD) located on the mitochondria was significantly decreased in Leydig cells exposed to cadmium, which suggested that DLD might be involved in the cytotoxic effects. Therefore, the altered expression of DLD was validated in rats and R2C cells exposed to cadmium, manganese and lead, and the role of DLD in the steroid synthesis pathway cAMP/PKA-ERK1/2 was investigated in this study. With a low expression of DLD, heavy metals dramatically reduced the levels of steroid hormone by inhibiting the activation of cAMP/PKA, PKC signaling pathway and the steroidogenic enzymes StAR, CYP11A1 and 3ß-HSD. After knockdown of DLD in R2C cells, progesterone synthesis was reduced by 40%, and the intracellular concentration of cAMP, protein expression of StAR, 3ß-HSD, PKA, and the phosphorylation of ERK1/2 were also decreased. These results highlight that DLD is down-regulation and related to steroid biosynthesis in Leyig cells exposed to heavy metals; cAMP/PKA act as downstream effector molecules of DLD, which activate phosphorylation of ERK1/2 to initiate the steroidogenesis.

Reactivation of the homeotic tumor suppressor gene CDX2 by 5-aza-2'-deoxycytidine-induced demethylation inhibits cell proliferation and induces caspase-independent apoptosis in gastric cancer cells.

The DNA methylation inhibitor 5-aza-2'-deoxycytidine (5-aza-CdR) is widely used as an anticancer drug for the treatment of leukemia and solid tumors. Gastric cancer (GC) patients who were positive for caudal type homeobox transcription factor 2 (CDX2) expression showed a higher survival rate compared with those who were CDX2 negative, which suggests that CDX2 performs a tumor suppressor role. However, the molecular mechanisms leading to the inactivation of CDX2 remain unclear. In the present study we demonstrated that the expression levels of CDX2 and DNA methyltransferase enzyme 1 (DNMT1) mRNA were significantly higher in GC compared with distal non-cancerous tissue. The expression of CDX2 mRNA was significantly correlated with Lauren classification, TNM stage and lymph node metastasis. DNMT1 mRNA expression was significantly correlated with TNM stage, pathological differentiation and lymph node metastasis. The expression of CDX2 mRNA was inversely correlated with that of DNMT1 mRNA in GC. Hypermethylation of the CDX2 gene promoter region, extremely low expression levels of CDX2 mRNA and no expression of CDX2 protein were the characteristics observed in MKN-45 and SGC-7901 GC cell lines. Following the treatment of MKN-45 cells with 5-aza-CdR, the hypermethylated CDX2 gene promoter region was demethylated and expression of CDX2 was upregulated, while DNMT1 expression was downregulated. Furthermore, a concentration- and time-dependent growth inhibition as well as increased apoptosis were observed. Caspase-3, -8 and -9 activities increased in a concentration-dependent manner following exposure to different concentrations of 5-aza-CdR. Therefore, our data show that the overexpression of DNMT1 and methylation of the CDX2 gene promoter region is likely to be responsible for CDX2 silencing in GC. 5-Aza-CdR may effectively induce re-expression of the CDX2 gene, inhibit cell proliferation and enhance the caspase-independent apoptosis of MKN-45 cells in vitro.

Ectopic expression of guanylyl cyclase C and endogenous ligand guanylin correlates significantly with Helicobacter pylori infection in gastric carcinogenesis.

The molecular mechanisms leading to gastric carcinogenesis still remain unclear. Recently, several studies demonstrated that over-expression of guanylyl cyclase C (GCC) has been detected in intestinal-type gastric cancer (GC) and precursor lesions. Our objective was to explore the expression levels of GCC and endogenous ligands guanylin (GN) and uroguanylin (UGN) and the correlation between Helicobacter pylori (H. pylori) and GCC, GN, and UGN expressions in patients at different stages from normal mucosa to superficial gastritis, atrophic gastritis, intestinal metaplasia (IM), dysplasia, and finally adenocarcinoma. The expression of GCC and GN was absent in the distal normal gastric tissues and superficial gastritis in all cases, whereas they were measured in IM, dysplasia, and GC. The expression of GCC and GN was closely related to intestinal-type GC. From superficial gastritis to gastric carcinomas, the H. pylori positive rate was 19.7, 33.3, 69.6, 80.0, and 82.1%, respectively. The positive correlation was found between GCC and GN in IM, dysplasia, and GC. Also, the positive correlation was found between GCC, GN, and H. pylori infection in them. These results demonstrate that the detection of GCC and GN will be beneficial to diagnosis human gastric carcinoma and precancerous lesions. Ectopic expression of GCC and GN in human gastric mucosa and H. pylori infection may play an important role in the carcinogenesis of the intestinal-type GC.

Transfusion of autologous late-outgrowth endothelial cells reduces arterial neointima formation after injury.

AIMS: Late-outgrowth endothelial cells (OECs) exist in blood and other organs. We aimed to explore whether and how OECs participate in re-endothelialization and prevent vascular neointima formation after injury. METHODS AND RESULTS: Rabbit bone marrow OECs were cultured for 4 weeks to increase their numbers. Transfusion of autologous OECs (2 × 106-1 × 107/kg) soon after rabbit ear central artery injury reduced the increase in intima area and the decrease in lumen area observed at days 14 and 28. Transfusion of autologous OECs (1 × 107/kg) ameliorated some early (days 2 and 7) inflammatory and angiogenic responses (local and systemic) to the injury. Red fluorescence was seen within 7 days after transfusion of 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine-labelled acetylated low-density lipoprotein (Dil-acLDL)-incorporated OECs, and 1 h after perfusion of the isolated rabbit ear with Ringer-Locke solution containing Dil-acLDL-incorporated OECs, in the injured rabbit ear central artery. After transfusion of 5-bromo-2'-deoxyuridine (BrdU) incorporated autologous OECs, BrdU-positive cells appeared in the injured artery intima at day 3 and were present in the rescued artery endothelium at day 28. The OECs, ranging from 5%-15% of vascular smooth muscle cells (VSMCs), and the OEC-conditioned medium (5-15%) both inhibited VSMC proliferation and migration in vitro and regulated the arrangement of VSMCs. The VSMCs were helpful for OECs to form tubes in vitro. CONCLUSION: Circulating OECs participate in re-endothelialization directly and inhibit VSMC migration and proliferation by a paracrine pathway; transfusion of large numbers of autologous OECs soon after vascular injury may prevent neointima formation.

Effect of atropine on denervated rabbit ear blood vessels.

Surgical denervation of rabbit ear blood vessel beds was combined with the isolated perfused rabbit ear technique to investigate the mechanism of atropine's vasodilator action. Intramuscular injection of atropine 0.2 mg/kg dilated the denervated blood vessels in the rabbit ear like innervated ones in vivo. Atropine at the maximal concentration (Cmax) of 3 x 10(-6) to 3 x 10(-4) M did not increase effluent flow of the isolated perfused denervated rabbit ear under constant perfusion pressure, but chlorpromazine at a Cmax of 10(-6) M and acetylcholine (ACh) at 2.5 x 10(-7) M significantly increased it and noradrenaline (NA) at 10(-7) M significantly decreased it. Atropine at Cmax of 3 x 10(-7) M did not affect, but at 3 x 10(-6) M it abolished the increase of the effluent flow induced by ACh 2.5 x 10(-7) M. Atropine at 3 x 10(-7) M did not affect it, but at 10(-6), 3 x 10(-6), and 10(-5) it significantly alleviated the decrease of effluent flow induced by NA 10(-7) M. Because the increase of effluent flow of rabbit ear under constant perfusion pressure reflects vasodilation of the ear to some extent, the study suggests that atropine has no direct vasodilator action; its vasodilator action is not attributed to blockade of M-cholinoreceptors located on the vascular wall; however, the alpha1-adrenoceptor might be a target site mediating atropine's vasodilator action in vivo.