Strontium fructose 1, 6-diphosphate alleviate cyclophosphamide-induced oligozoospermia by improving antioxidant and inhibiting testicular apoptosis via FAS/FASL pathway.

This study investigated the treatment effects of a new compound, strontium fructose 1, 6-diphosphate (FDP-Sr), in cyclophosphamide (CP)-induced oligozoospermia. FDP-Sr, with extra high-energy supply, could reverse male hypogonadism in the testis. Male Wistar rats were randomly divided into three groups: control group (vehicle treated), CP group and CP + FDP-Sr group. Both CP group and CP + FDP-Sr groups were orally administered CP (20 mg kg(-1) ) consecutively for the first 7 days to establish CP-induced testicular toxic models. Subsequently, CP group was given orally distilled water per day, whereas CP + FDP-Sr group was received FDP-Sr (200 mg kg(-1) ) for 49 days. Compared to the CP group, the FDP-Sr group showed significantly increased levels of serum testosterone, testis relative weights and epididymal sperm counts in rats. In addition, rats treated by FDP-Sr showed the recuperative activities of testicular marker enzymes and normalised levels of antioxidants in tissue. Testicular protection of FDP-Sr was further demonstrated by enhancing expression of P450scc, reducing ability of FAS/FASL and generating cytoprotection in the histopathological study. FDP-Sr appeared to possess an ability to attenuate CP-induced reproduction toxicity via the activation of antioxidants and steroidogenesis enzymes, and alleviate oligozoospermia via inhibition of testicular apoptosis by FAS/FASL pathway.

[To the mechanism of enhancing the activity of serum and hepatic sorbitol dehydrogenase in rats fed excess sweetener sorbitol].

One-month rats were randomized to a diet containing sorbitol (SOR) (54%), saccharose (SACCH) (54%) or that containing SOR (27%) and SACCH (27%). They were kept on the diets for 1 or 3 months. At the age of 2 and 4 months, the rats were returned to the routine diet of a vivarium. The experiments were terminated when the rats were aged 2, 4, and 7 months. In all seasons, the monthly diets containing 27% and 54% of SOR increased the serum activity of sortibol dehydrogenase (SDH) by several and tens of times. The 3-month diet produced the same effect. It suddenly turned out that the 54% SACCH diet also increased SDH activity, but to a lesser extent than a combination of 27 SOR and 27% SACCH, and by tens of times less than the 54% SOR diet. Comparison of three diets showed the same relationship between the increases in SDH activity in the liver. With excess dietary SOR, a very high increase was first found in serum and hepatic SOD activity by an induction mechanism.

Alpha-crystallin: an ATP-independent complete molecular chaperone toward sorbitol dehydrogenase.

alpha-Crystallin, the major component of the vertebrate lens, is known to interact with proteins undergoing denaturation and to protect them from aggregation phenomena. Bovine lens sorbitol dehydrogenase (SDH) was previously shown to be completely protected by alpha-crystallin from thermally induced aggregation and inactivation. Here we report that alpha-crystallin, in the presence of the SDH pyridine cofactor NAD(H), can exert a remarkable chaperone action by favoring the recovery of the enzyme activity from chemically denaturated SDH up to 77%. Indeed, even in the absence of the cofactor, alpha-crystallin present at a ratio with SDH of 20:1 (w:w) allows a recovery of 35% of the enzyme activity. The effect of ATP in enhancing alpha-crystallin-promoted SDH renaturation appears to be both nonspecific and to not involve hydrolysis phenomena, thus confirming that the chaperone action of alpha-crystallin is not dependent on ATP as energy donor.

p-Aminophenol-induced hepatotoxicity in hamsters: role of glutathione.

p-Aminophenol (PAP) is a widely used industrial chemical and a known nephrotoxin. Recently, it was found to also cause hepatotoxicity and glutathione (GSH) depletion in mice. The exact mechanism of liver toxicity is not known. The aims of this study were to determine whether PAP can cause acute hepatotoxicity in hamsters and to further investigate the role of GSH in PAP-induced toxicity. PAP was administered ip to hamsters in doses of 200-800 mg/kg. Liver damage at 24 h after PAP administration was assessed by elevations in plasma enzyme activities and histopathologic examination. GSH and cysteine (Cys) levels in liver at 4 h were determined by HPLC. PAP decreased hepatic GSH concentration to 8% and Cys to 30% of vehicle control values. It increased plasma glutamic pyruvic transaminase (GPT) activity by 47-fold and sorbitol dehydrogenase (SDH) activity by 113-fold. PAP also caused severe centrilobular hepatocellular necrosis. 2(RS)-n-Propylthiazolidine-4(R)-carboxylic acid (PTCA), a Cys precursor, attenuated the PAP-induced decreases in hepatic sulfhydryl levels; GSH and Cys were 39% and 78% of vehicle controls, respectively. PTCA also attenuated the PAP-induced elevations in plasma enzyme activities and hepatic necrosis. It was concluded that PAP hepatotoxicity is associated with depletion of hepatic GSH and can be prevented by PTCA.

[Effect of sodium fluoride on the activity of sorbitol dehydrogenase in plasma and liver of rabbits with experimental atherosclerosis]. / Wplyw fluorku sodu na aktywnosc dehydrogenazy sorbitolowej w osoczu i watrobie królików z doswiadczalna miazdzyca.

This study was done in rabbits placed on a low-cholesterol (0.5 g%) and high-cholesterol (2.0 g%) diet to induce experimental atherosclerosis. The intake of fluorine in the form of NaF in water was 3 mg F(-)/kg b.w./24 h. The activity of sorbitol dehydrogenase (SDH) was increased in plasma and decreased in the liver of rabbits on the high-cholesterol diet and in animals simultaneously exposed to NaF in water. Two months of the low-cholesterol diet produced an increase in SDH activity in plasma as a direct consequence of exposure to fluoride in the diet and presumably caused by accumulation of fluoride in the liver.

Combined transcriptome and proteome analysis as a powerful approach to study genes under glucose repression in Bacillus subtilis.

We used 2D protein gel electrophoresis and DNA microarray technologies to systematically analyze genes under glucose repression in B:acillus subtilis. In particular, we focused on genes expressed after the shift from glycolytic to gluconeogenic at the middle logarithmic phase of growth in a nutrient sporulation medium, which remained repressed by the addition of glucose. We also examined whether or not glucose repression of these genes was mediated by CcpA, the catabolite control protein of this bacterium. The wild-type and ccpA1 cells were grown with and without glucose, and their proteomes and transcriptomes were compared. 2D gel electrophoresis allowed us to identify 11 proteins, the synthesis of which was under glucose repression. Of these proteins, the synthesis of four (IolA, I, S and PckA) was under CcpA-independent control. Microarray analysis enabled us to detect 66 glucose-repressive genes, 22 of which (glmS, acoA, C, yisS, speD, gapB, pckA, yvdR, yxeF, iolA, B, C, D, E, F, G, H, I, J, R, S and yxbF ) were at least partially under CcpA-independent control. Furthermore, we found that CcpA and IolR, a repressor of the iol divergon, were involved in the glucose repression of the synthesis of inositol dehydrogenase encoded by iolG included in the above list. The CcpA-independent glucose repression of the iol genes appeared to be explained by inducer exclusion.

Protection of rat hepatocytes exposed to CCl4 in-vitro by cynandione A, a biacetophenone from Cynanchum wilfordii.

To identify hepatoprotective agents from plant sources we use primary cultures of rat hepatocytes injured by CCl4. The hepatoprotective agents are the compounds that mitigate the injury caused by CCl4. Using this system we have investigated the biochemical mechanisms involved in the hepatoprotective activity of cynandione A, a biacetopherone, isolated from the roots of Cynanchum wilfordii Hemsley (Asclepiadaceae). Cynandione A (50 microM) significantly reduced (approximately 50%) the release into the culture medium of glutamic pyruvic transaminase and sorbitol dehydrogenase from the primary cultures of rat hepatocytes exposed to CCl4. Glutathione, superoxide dismutase, catalase and glutathione reductase play important roles in the cellular defence against oxidative stress. Cynandione A appeared to protect primary cultured rat hepatocytes exposed to CCl4 from significant drops in the levels of each of these four specific markers. Cynandione A also ameliorated lipid peroxidation by up to 50% as demonstrated by a reduction in the production of malondialdehyde. These results suggest that cynandione A protected the hepatocytes from CCl4-injury by maintaining the level of glutathione and by inhibiting the production of malondialdehyde, due to its radical scavenging properties.

Effect of Emulphor, an emulsifier, on the pharmacokinetics and hepatotoxicity of oral carbon tetrachloride in the rat.

Emulphor, a polyethoxylated vegetable oil, is now being used widely to incorporate volatile organic compounds (VOCs) and other lipophilic compounds into aqueous solutions for biochemical, pharmacokinetic, and toxicological studies. Previous work in this laboratory demonstrated that 0.25% Emulphor did not alter the kinetics or hepatotoxicity of low doses of CCl4 compared to when the halocarbon was given to rats orally in water. The present study was undertaken as there was concern that higher concentrations of Emulphor (necessary to maintain lipophilic VOCs in stable aqueous emulsions for extended periods) might alter the VOCs' absorption, disposition, and/or toxicity. Dosages of 10 and 180 mg CCl4/kg bw were given, as an aqueous emulsion using 1, 2.5, 5, or 10% Emulphor, by gavage to fasted male Sprague-Dawley rats. Serial microsamples of blood were collected from an indwelling cannula in unanesthetized, freely moving rats at intervals of 2-60 min for up to 12 hr. The samples' CCl4 content was measured by headspace gas chromatography. Thereby, it was possible to obtain blood CCl4 concentration-versus-time profiles. Animals were euthanized 24 hr postdosing and blood was collected for measurement of serum enzymes as indices of hepatotoxicity. No toxicologically significant differences in pharmacokinetic parameters as a function of Emulphor concentration were found. Similarly the hepatotoxic potency of 10 and 180 mg/kg CCl4, as reflected by elevation in serum enzyme activities, did not vary significantly with the concentration of Emulphor utilized. Hence, it can be concluded that Emulphor, in concentrations as high as 10% (equivalent to 260 mg Emulphor/kg bw) in aqueous emulsions, does not significantly affect the absorption, disposition, or acute hepatotoxicity of CCl4 in male Sprague-Dawley rats.

Dichloromethane potentiation of carbon tetrachloride hepatotoxicity in rats.

Concomitant treatment of rats with a nonhepatotoxic dose of dichloromethane (6 mmol/kg, i.p.) significantly potentiated the hepatotoxicity of carbon tetrachloride (2 mmol/kg, i.p.). Toxicity was determined by increases in serum sorbitol dehydrogenase and alanine aminotransferase activities measured 24 hr following the treatments. Dichloromethane did not affect the lipid peroxidation induced by carbon tetrachloride as determined by conjugated diene formation in hepatic microsomal lipids. The covalent binding of [14C]Cl4 metabolites to microsomal lipids was increased significantly by dichloromethane. The results suggest that dichloromethane potentiates carbon tetrachloride hepatotoxicity by increasing covalent binding of its metabolites to hepatic microsomal lipids.

Effect of antispermatogenic compound CDRI-84/35 on marker enzymes of rat testis cells. A study on site of action.

Marker enzymes of Sertoli and germ cells were estimated to study the mechanism of action of antispermatogenic compound CDRI 84/35 in adult male rat testis. Animals were killed after 22, 41, and 64 days of treatment with antispermatogenic dose of CDRI 84/35 in order to evaluate the effect of the compound on spermatid, spermatocyte, and spermatogonial stages, respectively. Studies were also extended to a recovery period of 90 days. Results indicate a direction action of the compound on germ cells, with no apparent effect on Sertoli cells. Studies also show a massive depletion of postmeiotic germ cells after the treatment, with some damage to premeiotic germ cells as well. Reversibility of the compound was partial, with the marker enzymes of pre- and postmeiotic germ cells not being restored to control levels after withdrawal of treatment.

Formation of GSH-derivatives as a pathway for inactive intermediates in vinylidene chloride-treated rats.

The two conjugates, S-[N-(2-hydroxyethyl)carbamoylmethyl]glutathione (GSAAE), and its corresponding mercapturic derivative N-acetyl-S-[N-(2-hydroxyethyl)carbamoylmethyl]cysteine (NCySAAE) were administered to fasted Sprague-Dawley rats as putative metabolites of vinylidene chloride (VDC). Methylthioacetylaminoethanol (MAAE) was identified in the urine of GSAAE- or NCySAAE-treated rats (0.5-2.0 mmol/kg, i.p.), as well as in the urine of VDC-treated rats (0.5-2.0 mmol/kg, p.o.). The effects of VDC, GSAAE and NCySAAE on the kidney and liver were also examined using aspartate aminotransferase (ASAT). N-acetyl-beta-D-glucosaminidase (NAG) and beta 2-microglobulin (beta 2-m) as urinary parameters of nephrotoxicity, and glutamate dehydrogenase (GLDH), sorbitol dehydrogenase (SDH) and alanine aminotransferase (ALAT) as serum parameters of hepatotoxicity. Unlike treatment with VDC, treatment with both GSAAE and NCySAAE failed to cause kidney and liver toxicity. The results support the hypothesis that MAAE originates from the formation of GSAAE and further metabolization to NCySAAE, and that MAAE excretion does not reveal a pathway of reactive intermediates.

Testicular lactate dehydrogenase and sorbitol dehydrogenase activity after intratesticular injection of dynorphin and morphine in male rats.

Testicular lactate dehydrogenase (LDH) and sorbitol dehydrogenase (SDH) activity were measured at 1 and 4 hr following intratesticular injection of morphine and dynorphin. Twenty five and 50 micrograms doses of morphine sulfate significantly reduced LDH activity at 1 hr after injection. Five and 25 micrograms doses of dynorphin reduced LDH activity both at 1 and 4 hr after treatment. Testicular SDH activity was increased by morphine at 1 hr followed by a decrease at 4 hr. Both doses of dynorphin significantly reduced SDH activity at 1 and 4 hr after treatment. These results indicate paracrine regulatory role for opioids in testicular metabolism.

The effects of 10 triterpenoid compounds on experimental liver injury in mice.

The purpose of this study was to compare the hepatoprotective effects of 10 oleanane-type triterpenoid compounds on three known hepatotoxicants in mice. These compounds include oleanolic acid, ursolic acid, uvaol, alpha-hederin (alpha-H), hederagenin, glycyrrhizin, 18 alpha-glycyrrhetinic acid (alpha-GA), 18 beta-glycyrrhetinic acid (beta-GA), 19 alpha-hydroxyl asiatic acid 28-O-beta-D-glucoside (HAG), and 19 alpha-hydroxyl asiatic acid (HA). They were administrated sc for 3 days at 200 mumol/kg, except for alpha-H, which was given at 100 mumol/kg for 2 days. Acute liver injury was produced in male CF-1 mice by CCl4 (15 microliters/kg, ip), acetaminophen (500 mg/kg, ip), and cadmium chloride (3.7 mg/kg, iv). Liver damage was assessed by serum activities of alanine aminotransferase and sorbitol dehydrogenase, as well as by histopathological examination. alpha-Hederin, ursolic acid, and oleanolic acid markedly decreased the toxicity produced by all three hepatotoxicants. Uvaol significantly decreased CCl4- and Cd-induced hepatotoxicity, but had no effect on acetaminophen toxicity. Glycyrrhizin, alpha-GA, and beta-GA decreased acetaminophen-induced liver injury, whereas hederagenin, HAG, and HA did not protect against any of the hepatotoxicants. In addition, alpha-hederin, ursolic acid, oleanolic acid, and uvaol increased hepatic metallothionein levels by 87-, 48-, 28-, and 10-fold, respectively, as determined by the Cd/hemoglobin assay. In conclusion, among the 10 triterpenoid compounds examined, alpha-hederin, ursolic acid, and oleanolic acid appear to be the most effective in protecting against CCl4-, acetaminophen-, and Cd-induced liver injury.

Nephrotoxicity of paracetamol in the rat--mechanistic and therapeutic aspects.

Besides hepatotoxicity, paracetamol may exert nephrotoxic effects in experimental animals and patients. The present study in rats shows that antidotes known to protect against hepatotoxicity, such as methionine or N-acetylcysteine, are not effective in preventing paracetamol-induced kidney damage. Only diethyldithiocarbamate, an inhibitor of microsomal monooxygenases, provided complete protection against both hepato- and nephrotoxicity. While a marked depletion of glutathione was observed in the liver, no such effect was seen in the kidney. These data suggest that the mechanism of paracetamol nephrotoxicity seems to be quite different from that responsible for the hepatotoxicity. The hypothesis that a C-S-lyase-mediated final metabolism of paracetamol-S conjugates in the kidney might be responsible for nephrotoxicity needs support by further experimental investigations.