Effects of Iron Supplementation on Testicular Function and Spermatogenesis of Iron-Deficient Rats.

Iron deficiency is the most common micronutrient deficiency in the world. Previous studies have shown that iron deficiency increases oxidative stress and decreases antioxidant enzymes, and studies of male infertility indicated that oxidative stress may affect male reproductive functions. The aim of this study was to investigate the effects of iron supplementation on spermatogenesis and testicular functions in iron-deficient rats. Three-week-old male Sprague Dawley (SD) rats were randomly divided into two groups: an iron-adequate control (AI group, 35 ppm FeSO4) and an iron-deficient group (ID group, <5 ppm FeSO4). After three weeks, the iron-deficient group was divided into an original iron-deficient group and five iron-supplemented groups, the latter fed diets containing different doses of FeSO4 (6, 12, 18, 24, and 35 ppm). After five weeks, blood and testis tissue were analyzed. We presented as median (interquartile range, IQR) for continuous measurements and compared their differences using the Kruskal−Wallis test followed by the Mann−Whitney U test among groups. The results showed that as compared with the AI group, the ID group had significantly lower serum testosterone and poorer spermatogenesis (The medians (QR) were 187.4 (185.6−190.8) of AI group vs. 87.5 (85.7−90.4) of ID group in serum testosterone, p < 0.05; 9.3 (8.8−10.6) of AI group vs. 4.9 (3.4−5.4) of ID group in mean testicular biopsy score (MTBS], p < 0.05); iron supplementation reversed the impairment of testis tissue. In the testosterone biosynthesis pathway, iron supplementation improved the lowered protein expressions of hydroxysteroid dehydrogenases caused by iron deficiency. Additionally, decreased activities of glutathione peroxidase and catalase, and increased cleaved-caspase 8 and caspase 3 expression, were found in the iron-deficient rats. The iron-supplemented rats that received > 12 ppm FeSO4 exhibited improvements in antioxidant levels. In conclusion, iron supplementation can abrogate testis dysfunction due to iron deficiency through regulation of the testicular antioxidant capacity.

HTDP-2, a new synthetic compound, inhibits glutamate release through reduction of voltage-dependent Ca²âº influx in rat cerebral cortex nerve terminals.

AIM: The present study was aimed at investigating the effect of trans-6-(4-chlorobutyl)-5-hydroxy-4-(phenylthio)-1-tosyl-5,6-dihydropyridine-2(1H)-one (HTDP-2), a novel synthetic compound, on the release of endogenous glutamate in rat cerebrocortical nerve terminals (synaptosomes) and exploring the possible mechanism. METHODS: The release of glutamate was evoked by the K⁺ channel blocker 4-aminopyridine (4-AP) and measured by an on-line enzyme-coupled fluorimetric assay. We also used a membrane potential-sensitive dye to assay nerve terminal excitability and depolarization, and a Ca²âº indicator, Fura-2-acetoxymethyl ester, to monitor cytosolic Ca²âº concentrations ([Ca²âº](c)). RESULTS: HTDP-2 inhibited the release of glutamate evoked by 4-AP in a concentration-dependent manner. Inhibition of glutamate release by HTDP-2 was prevented by the chelating intraterminal Ca²âº ions, and by the vesicular transporter inhibitor bafilomycin A1, but was insensitive to the glutamate transporter inhibitor DL-threo-ß-benzyloxyaspartate. HTDP-2 did not alter the resting synaptosomal membrane potential or 4-AP-mediated depolarization whereas it decreased the 4-AP-induced increase in [Ca²âº](c). Furthermore, the inhibitory effect of HTDP-2 on the evoked glutamate release was abolished by the N-, and P/Q-type Ca²âº channel blocker ω-conotoxin MVIIC, but not by the ryanodine receptor blocker dantrolene, or the mitochondrial Na⁺/Ca²âº exchanger blocker CGP37157. CONCLUSION: Based on these results, we suggest that, in rat cerebrocortical nerve terminals, HTDP-2 decreases voltage-dependent Ca²âº channel activity and, in so doing, inhibits the evoked glutamate release.

The isolated and combined effects of folic acid and synthetic bioactive compounds against Abeta(25-35)-induced toxicity in human microglial cells.

Folic acid plays an important role in neuronal development. A series of newly synthesized bioactive compounds (NSCs) was reported to exhibit immunoactive and neuroprotective functions. The isolated and combined effects of folic acid and NSCs against beta-amyloid (Abeta)-induced cytotoxicity are poorly understood. These effects were tested using human microglia cells (C13NJ) subjected to Abeta(25-35) challenge. According to an MTT assay, treatment of C13NJ cells with Abeta(25-35) at 10-100 microM for 48 h induced 18%-43% cellular death in a dose-dependent manner (p < 0.05). Abeta(25-35) treatment at 25 microM induced nitrite oxide (NO) release, elevated superoxide production, and reduced the distribution of cells in the S phase. Preincubation of C13NJ with 100 microM folic acid protected against Abeta(25-35)-induced cell death, which coincided with a reduction in NO release by folic acid supplements. NSC47 at a level of 50 microM protected against Abeta(25-35)-induced cell death and reduced Abeta-promoted superoxide production (p < 0.05). Folic acid in combination with NSC47 at their cytoprotective doses did not synergistically ameliorate Abeta(25-35)-associated NO release, superoxide production, or cell cycle arrest. Taken together, folic acid or NSC treatment alone, but not the combined regimen, protected against Abeta(25-35)-induced cell death, which may partially, if not completely, be mediated by free radical-scavenging effects.

A new synthetic compound, 2-OH, enhances interleukin-2 and interferon-gamma gene expression in human peripheral blood mononuclear cells.

A new synthetic compound, 6-hydroxy-2-tosylisoquinolin-1(2H)-one (2-OH), was selected for immunopharmacological activity tests. The effects of 2-OH on human peripheral blood mononuclear cell (PBMC) proliferation were determined by tritiated thymidine uptake. Compared to phytohemagglutinin (PHA; 5 microg/mL) stimulation, 2-OH significantly enhanced PBMC proliferation in a dose-dependent manner. The 50% enhancement activity (EC(50)) for 2-OH was 4.4+/-0.1 microM. In addition, effects of 2-OH on interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) production in PBMC were determined by enzyme immunoassay. Results demonstrated that 2-OH stimulated IL-2 and IFN-gamma production in PBMC. Data from reverse transcription-polymerase chain reaction (RT-PCR) and real-time PCR indicated that IL-2 and IFN-gamma mRNA expression in PBMC could be induced by 2-OH. Therefore, 2-OH enhanced IL-2 and IFN-gamma production in PBMC by modulation their gene expression. We suggest that 2-OH may be an immunomodulatory agent.

HDT-1, a new synthetic compound, inhibits glutamate release in rat cerebral cortex nerve terminals (synaptosomes).

AIM: Excessive glutamate release has been proposed to be involved in the pathogenesis of several neurological diseases. In this study, we investigated the effect of HDT-1 (3, 4, 4a, 5, 8, 8a-hexahydro-6,7-dimethyl-4a-(phenylsulfonyl)- 2-tosylisoquinolin-1(2H)-one), a novel synthetic compound, on glutamate release in rat cerebrocortical nerve terminals and explored the possible mechanism. METHODS: The release of glutamate was evoked by the K+ channel blocker 4-aminopyridine (4-AP) or the high external [K+] and measured by one-line enzyme-coupled fluorometric assay. We also determined the loci at which HDT-1 impinges on cerebrocortical nerve terminals by using membrane potentialsensitive dye to assay nerve terminal excitability and depolarization, and Ca2+ indicator Fura-2 to monitor Ca2+ influx. RESULTS: HDT-1 inhibited the release of glutamate evoked by 4-AP and KCl in a concentration-dependent manner. HDT-1 did not alter the resting synaptosomal membrane potential or 4-APevoked depolarization. Examination of the effect of HDT-1 on cytosolic [Ca2+] revealed that the diminution of glutamate release could be attributed to reduction in voltage-dependent Ca2+ influx. Consistent with this, the HDT-1-mediated inhibition of glutamate release was significantly prevented in synaptosomes pretreated with the N- and P/Q-type Ca2+ channel blocker omega-conotoxin MVIIC. CONCLUSION: In rat cerebrocortical nerve terminals, HDT-1 inhibits glutamate release through a reduction of voltage-dependent Ca2+ channel activity and subsequent decrease of Ca2+ influx into nerve terminals, rather than any upstream effect on nerve terminal excitability.

Mitochondrial cysteine desulfurase iron-sulfur cluster S and aconitase are post-transcriptionally regulated by dietary iron in skeletal muscle of rats.

Cysteine desulfurase IscS is required for cellular iron-sulfur protein maturation in eukaryotes and prokaryotes. In this study, we examined the effect of dietary iron intake on the expression in rat skeletal muscle of IscS in relation to 2 iron-sulfur proteins, cytosolic aconitase (c-aconitase) and mitochondrial aconitase (m-aconitase). Three groups of male weanling Wistar rats were used; 1 group was fed an iron-deficient diet (D), and the other 2 groups were pair-fed (P) or freely fed (C) a control (35 mg Fe/kg diet) diet for 1 or 2 wk. At the end of wk 1 and 2, the mitochondrial IscS protein levels in the skeletal muscle of iron-deficient rats had decreased to 45 and 50% of those of the control and pair-fed rats, respectively, whereas the IscS mRNA levels did not differ among the 3 groups, indicating that iron deficiency affected the expression of IscS protein at the post-transcriptional level. Iron deficiency caused a 55-76% reduction in c-aconitase activity and an approximately 50% reduction in the c-aconitase protein level. The m-aconitase activity and protein level in iron-deficient rats also declined to 50 and 58-64% of the control levels, respectively. Our results indicate that dietary iron modulates mitochondrial IscS protein and aconitase at the post-transcriptional level, and mitochondrial IscS may be associated with this regulation of aconitase in skeletal muscle.