Differential binding of (+) and (-) gossypol to plasma protein and their entry into rat testis

MiR-214_L-1R+4 regulate gossypol-induced immune response through MyD88-dependent signaling pathway in Cyprinus carpio

MicroRNAs (miRNAs) have been demonstrated to act as crucial modulators with considerable impacts on the immune system. Cottonseed meal is often used as a protein source in aqua feed, cottonseed meal contains gossypol, which is harmful to animals. However, there is a lack of research on the role of miRNAs in fish exposed to gossypol stress. To determine the regulatory effects of miRNAs on gossypol toxicity, Cyprinus carpio were given to oral administration of 20 mg/kg gossypol for 7 days, and the gossypol concentration in the tissues was tested. Then, we detected spleen index, histology, immune enzyme activities of fish induced by gossypol. The results of miRNA sequencing revealed 8 differentially expressed miRNAs in gossypol group, and miR-214_L-1R+4 was found involved in immune response induced by gossypol. The potential targets of miR-214_L-1R+4 were predicted, and found a putative miR-214_L-1R+4 binding site in the 3'UTR of MyD88a. Furthermore, dual-luciferase reporter assays displayed miR-214_L-1R+4 decreased MyD88a expression through binding to the 3'UTR of MyD88a. Moreover, miR-214_L-1R+4 antagomir were intraperitoneally administered to C. carpio, down-regulated miR-214_L-1R+4 could increase MyD88a expression, as well as inflammatory cytokines and anti-inflammatory cytokines expression. These findings revealed that miR-214_L-1R+4 via the MyD88-dependent signaling pathway modulate the immune response to gossypol in C. carpio spleen.

Aqueous Extract of Adansonia digitata reversed Cotton Seed Extract-Induced Testicular Damage in Wistar rats

Objective:

Infertility is the inability of sexually active couples without using birth control to get pregnant after one year of uninterrupted sexual intercourse. Cotton Seed Extract (CSE) has been linked to male infertility by causing oxidative damage to the testes due to the action of its active component, Gossypol. Adansonia digitata has been known to have many medically useful properties, including antioxidant effects. This study aimed at evaluating the effects of Adansonia digitata on Cottonseed extract-induced testicular damage.

Methods:

Forty (40) Adult male Wistar rats were divided into 8 groups of five rats per group (n=5). Group 1 served as the control and received 0.5 ml of phosphate buffer orally; Group 2 received 800 mg/kg b.wt A. digitata orally; Group 3 received 300 mg/kg b.wt Vitamin E only orally; Group 4 received 60 mg/kg b.wt CSE intraperitoneally; Group 5 received 20 mg/kg b.wt CSE intraperitoneally; Group 6 received 60 mg/kg b.wt CSE intraperitoneally and 800 mg/kg b.wt A. digitata orally; Group 7 received 20 mg/kg b.wt CSE intraperitoneally and 800 mg/kg b.wt A. digitata orally; Group 8 received 60 mg/kg b.wt CSE intraperitoneally and 300 mg/kg Vit. E orally. It was administered for 21 days. The testes and epididymis were dissected following abdominal incision. The epididymis was used for semen analysis while the testes was processed for histological analysis and biochemical assay. All the data was analyzed by ANOVA, using the SPSS version 17.0 software. A p<0.05 was considered significant.

Results:

CSE administration caused significant (p<0.05) decrease in sperm count, found in the group treated with CSE only. However, the Administration of A. digitata caused significant increase (p<0.05) in sperm count, G6PDH, LDH, GPx and SOD; however, MDA levels were decreased. Histological observations showed a decrease in the number of Spermatogonia and differentiating cells in the testes of rats treated with CSE.

Conclusions:

The results obtained revealed the antioxidant ability of A. digitata in counter-acting the testicular damage caused by CSE administration.

Effects of sublethal doses of gossypol on haematological properties and biochemical metabolites of male rabbit

The purpose of this study was to investigate the effects of two sublethal doses of gossypol (GOS) (4 and 20 mg/kg of body weight), administered every other day, on some haematological, biochemical, enzymatic and electrolytic properties and amino and fatty acids in male rabbit blood plasma. The experiment lasted for 16 wk and included two phases: 1) administration period; rabbits were given the experimental doses of GOS for 8 wk; and 2) recovery period; rabbits were allowed 8 wk for complete withdrawal of drugs from the plasma. Results showed that low levels of gossypol increased (<em>P</em>&lt;0.01) haemoglobin, mean corpuscular haemoglobin and white blood cells compared to control. Plasma total protein was increased (<em>P</em>&lt;0.01) by the low GOS dose in both experimental phases. Likewise, glucose concentration was increased (<em>P</em>&lt;0.01) by the high GOS dose during the recovery period. Aspartate aminotransferase and alanine aminotransferase enzymes were increased (<em>P</em>&lt;0.01) by the high dose of GOS treatment only. Low GOS dose increased (<em>P</em>&lt;0.01) blood plasma Na+ concentration in the recovery period only. Results revealed that total essential amino acids (EAA), and EAA/non-EAA ratio were not affected in a dose-dependent manner during the treatment phase expect for plasma proline, which was increased along with non-EAA (<em>P</em>&lt;0.01) by high GOS dose. Additionally, GOS administration did not affect total unsaturated fatty acids (USFA), total saturated fatty acids (SFA) and SFA/USFA ratio in a dose-dependent manner. In conclusion, Gossypol treatment affected rabbit haematological parameters and biochemical properties of blood plasma in a dose-dependent manner.

Tautomerism and stereodynamics in Schiff bases from gossypol and hemigossypol with N-aminoheterocycles

Gossypol, a natural male contraceptive, can be functionalized via dynamic imine linkages, whose tautomerism has been explored in detail.

Pharmacokinetic comparison of gossypol isomers in cattle: transfer from diet to plasma and degradation by rumen microbes*#

A pharmacokinetic comparison of gossypol isomers in cattle was made by investigating their transfer from ingested food to plasma and their degradation by rumen microbes. The gossypol isomers in whole cottonseed, plasma, and rumen fluid were determined by high-performance liquid chromatography (HPLC). The intakes of (+)-and (−)-gossypol by cows on three farms were about 5.6–8.5 and 3.8–5.9 g/(d·herd), respectively. The plasma gossypol concentrations increased as ingestion increased and ranged from 0.31 to 0.48 μg/ml for the (+) form and from 0.39 to 0.59 μg/ml for the (−) form. The (+) form was slightly predominant (58.8%–59.8%) in the gossypol ingested by the cows, whereas the (−) form predominated (54.6%–55.9%) in the plasma. An in vitro study showed that at 6 h, 67.4% and 85.7% of the (−)-gossypol were degraded in 500 and 1000 μg/g treatment groups, respectively, and these increased to 83.6% and 92.5%, respectively, at 12 h. The regularity of the degradation of (+)-gossypol was similar to that of (−)-gossypol. These results showed that (−)-gossypol may be more persistent than (+)-gossypol in plasma, and that the degradation of the gossypol isomers in the rumen is rapid and not enantioselective in cattle.

Development of an RP-UHPLC-PDA method for quantification of free gossypol in cottonseed cake and fungal-treated cottonseed cake

Cottonseed cake biomass, which is a residue of oil extraction, is potentially appropriate for use as animal feed, given the high mineral, fibre and protein content. The presence of free gossypol, however, a toxic pigment in the glands of the cotton plant, limits use of this biomass for monogastric livestock. A promising method to detoxify cottonseed cake relies on fermentation by fungi, which can eliminate up to 100% of gossypol. In order to quantify trace levels of free gossypol in different cotton materials, including cottonseed cake treated with macrofungi, a simple and rapid chromatographic detection method was developed and validated. Under optimized conditions, extraction was performed using 70% acetone. The extract was then analysed by Ultra High-Performance Liquid Chromatography (UHPLC), with gradient elution on a C18 reverse phase column KINETEX^® (100 x 2.10 mm, 2.6 μm). Methanol-0.1% TFA aqueous solution was employed as mobile phase and PDA detection conducted at 254 nm. The optimized method was validated by analysis of specificity, linearity and range, limit of detection, limit of quantification, precision and accuracy. Detection and quantification limits were observed at 0.2 and 0.5 μg/mL, respectively. With good reproducibility, with precision (RSD)<10% and recovery greater than 94%, the developed assay was appropriate for quantification of low quantities of free gossypol. The validated method was successfully applied to determine trace levels of free gossypol cottonseed treated with a macrofungus.

Quantitative determination of apogossypol, a pro-apoptotic analog of gossypol, in mouse plasma using LC/MS/MS

A simple and selective liquid chromatography/tandem mass spectrometry (LC/MS/MS) method based on internal standard quantitation using apigenin as the internal standard has been developed and validated for the analysis of the gossypol analog apogossypol, a pro-apoptotic compound, in mouse plasma. The methodology involves protein precipitation of plasma samples followed by LC/MS/MS analysis. Ascorbic acid was added to the spiking solutions and plasma samples to stabilize the easily oxidized compound. Separation of apogossypol and the internal standard from the plasma matrix was achieved using a C18 column with a gradient elution profile consisting of 5mM ammonium acetate and methanol. The validated range of the method extended from 10 to 2000 ng/mL with accuracies of 85-115% and precision of <15%. The average recovery of apogossypol at three concentrations (50, 200 and 1000 ng/mL) assayed in triplicate using this methodology was determined to be 90.8+/-12.9%. Recovery for the internal standard (apigenin) at a concentration of 500 ng/mL was found to be 99.9+/-6.41%. Apogossypol concentrations of 50 ng/mL and above were found to be stable in extracted plasma for 24h when stored at 25 degrees C. This method has been applied to the determination of apogossypol concentrations in plasma collected from mice given an IV dose of apogossypol.

Effects of gossypol from cottonseed on hematological responses and plasma alpha-tocopherol concentration of dairy cows

The effects of feeding whole cottonseed (WCS) and bovine somatotropin (bST) administration on hematological responses and plasma alpha-tocopherol concentrations of lactating dairy cattle were examined. After parturition, multi and primiparous Holstein cows (n = 159) were assigned randomly to a 2 x 2 factorial arrangement of treatments consisting of (0 or 15% WCS and 0 or 208 mg of bST injected every 2 wk starting within 7 d after calving. Blood samples were collected from a subset group of 64 cows at 14, 28, 42, and 56 d postpartum. Blood was collected from all cows (n = 159) at 75, 96 and 120 d postpartum. Blood samples were analyzed for alpha-tocopherol and total and (+)- and (-)-gossypol in plasma. Erythrocyte osmotic fragility, hemoglobin and hematocrit also were determined in blood. The mean concentrations of alpha-Tocopherol, total, and (+)- and (-)-gossypol were higher in cows fed WCS regardless of bST administration and plateaued by d 75 postpartum. Hematocrit and hemoglobin concentrations were not affected by treatments. Erythrocyte osmotic fragility was higher in cows fed WCS, but the increase was attenuated when bST was injected (diet x bST interaction). No clinical signs of gossypol toxicity were observed in the cows consuming the WCS.

High-performance liquid chromatographic determination of gossypol and gossypolone enantiomers in fish tissues using simultaneous electrochemical and ultraviolet detectors

There is a need to measure dietary transfer of gossypol and its metabolite, gossypolone in aquatic animals because of common use of cottonseed meal as a feed ingredient and fertilizer. The analytical method for gossypol and gossypolone enantiomers, therefore, becomes important. HPLC techniques have been developed by using mainly UV detection. We simultaneously used both UV and electrochemical (EC) detectors, and found that each individual detector has its own advantage which can increase accuracy and ease of identification. EC detection (2.5 and 50 ng/ml) exhibited a significantly lower detection level for both gossypol and gossypolone enantiomers than the UV detection (40 and 300 ng/ml) in the rainbow trout tissues, while UV detectors showed more stable detection than EC. We were able to detect a very low concentration of each gossypol enantiomer by EC but not UV detection especially in seminal plasma. For the first time gossypolone enantiomers were quantified in fish tissues by HPLC and its method was described. The technique, simultaneous adoption of both UV and EC detectors, could be helpful for a very low concentration of gossypol and/or gossypolone enantiomers in tissues of other animals and humans.

Gossypol isomers bind specifically to blood plasma proteins and spermatozoa of rainbow trout fed diets containing cottonseed meal

We investigated the role of gossypol isomers binding to blood plasma, seminal plasma and spermatozoa to elucidate gossypol anti-fertility action in the teleost fish, rainbow trout (Oncorhynchus mykiss). Growth and hematological indicators of males were depressed when fish meal protein in diets was completely replaced with cottonseed meal. The cottonseed meal contained equal proportions of (-) (47.8+/-1.6%) and (+) gossypol isomers. Concentrations of spermatozoa were decreased with increasing proportions of gossypol in diets (from 0.22% to 0.95%); however, sperm motility and fertilizing ability were not affected. In contrast to mammals, steroid hormone concentrations were not suppressed in fish given diets with gradual increase of gossypol level. Gossypol concentrations were 100-fold higher in blood plasma than in seminal plasma, confirming a barrier in gossypol transfer between the general circulation and the testis. Spermatozoa accumulated predominantly (+) enantiomer (65-75%) with decreasing proportions as dietary gossypol concentrations increased. Spermatozoa bound most of the gossypol contained in the semen; however, this did not result in impairment of the sperm motility apparatus. Teleost fish sperm rely on ATP stores that accumulate during maturation as a source of energy during activation. In addition, the duration of sperm movement is short in these fish. As such, we hypothesize that the major action of gossypol on mammalian sperm, which is uncoupling of oxidative phosphorylation, does not impair the energy supply required for flagellar beating in fish spermatozoa.

Effects of gossypol on sperm viability and plasma sex steroid hormones in male sea lamprey, Petromyzon marinus

Male sea lampreys Petromyzon marinus were injected with different doses of gossypol acetic acid in an attempt to sterilize them for use in a program for controlling the sea lampreys through the release of sterile males. Two lots of sea lamprey were used in these experiments. The first lot was divided into three groups and fish were injected intraperitoneally (i.p.) with 0.2 ml 50% ethanol as a control group or with gossypol suspended in ethanol at 100 and 200 mg/kg. The second lot was also divided into three groups and fish were either injected i.p. with vehicle as controls or gossypol at 25 and 50 mg/kg. Sperm weight, concentrations and motility were recorded after 31, 36 and 40 days or 24, 28 and 33 days in lots 1 and 2, respectively. Blood was collected from the caudal vessel prior to injections with gossypol and after 40 or 33 days in lots 1 and 2, respectively. Plasma levels of estradiol-17beta (E2), testosterone (T), progesterone (P) and 17,20beta-dihydroxy-4-pregnen-3-one (17,20betaP) were measured by radioimmunoassay. At the end of the experiment, the testis were removed and fixed in Bouin's solution for histological examination. High mortality was observed at the day of injection in the group treated with 200 mg/kg (84.6%), 100 mg/kg (41.7%), and 50 mg/kg (25%). Sperm concentrations were higher in control fish in comparison to most of the treated groups during the first sperm sampling (day 31 or 24), but then differences disappeared. At each sampling, sperm motility was higher in control groups than in treated groups and significant differences were observed (e.g. between control and 50 mg gossypol/kg). Fertility, evaluated at optimized sperm/egg ratio (5 x 10(4) sperm/egg) did not differ among treatments and controls. Changes in mean plasma sex steroid levels in the various treated groups were not significant, but a trend of decreasing plasma E2 was observed with increasing dose of gossypol. The structure of the testis was examined at the end of the experiment using light microscopy and appeared to be unchanged in gossypol-treated lampreys as compared to that of control animals. These findings suggest that gossypol injection into lamprey interferes with some of the reproductive parameters. Although high mortality rate precludes a single i.p. injection of gossypol as a favorable mode of chemosterilization in the lamprey, it would be useful to reassess the means of transfer of gossypol to reproductive tissues. This notion is further supported by the results of an in vitro sperm toxicity assay which revealed that gossypol, at a dose of 100 microM, has an antifertility action in this species.

Long-term effects of gossypol and vitamin E in the diets of dairy bulls

Long-term effects of the inclusion of cottonseed meal in the diet on hematological and tissue parameters of Holstein bulls were investigated. Twenty-four Holstein bulls that were approximately 6 mo of age received the following treatments for 10 mo: 1) soybean meal plus 30 IU of vitamin E/kg, 2) cottonseed meal plus 30 IU of vitamin E/kg, and 3) cottonseed meal plus 4000 IU of vitamin E/d per bull. Treatments 2 and 3 were formulated to supply 14 mg of free gossypol/kg of body weight per d. Average daily gain, total gain, and final body weights were not affected by treatment. The osmotic fragility of erythrocytes was greater during all collection periods for bulls on treatments 2 and 3 than for bulls on treatment 1. The inclusion of 4000 IU of vitamin E/d per bull did not reduce the increase in the osmotic fragility of erythrocytes that was caused by gossypol. Bulls on treatment 3 had higher plasma alpha-tocopherol concentrations than did bulls on treatments 1 and 2. Vitamin E supplementation did not affect gossypol concentrations in plasma or tissue. The highest gossypol concentrations were found in the liver followed by the heart and testis. In vitro lipid peroxidation of tissue indicated that gossypol acts as an antioxidant in lipid peroxidation systems, and its role as an antioxidant may be dependent on dose or tissue. Cottonseed meal in the diets of bulls did not affect growth or vitamin E status.

Effect of gossypol on cultured TM3 Leydig and TM4 Sertoli cells: 31P and 23Na NMR study

The effects of gossypol on glucose metabolism, ATP levels and intracellular sodium levels in murine TM3 Leydig and TM4 Sertoli cell lines were investigated, and their response compared. Relative ATP levels and sodium ion levels in the two cell lines were determined by 31P and 23Na NMR spectroscopy. Short-term effect of gossypol on phosphate metabolism in immobilized and perfused cells was apparent in 31P NMR spectra only with relatively high concentrations of gossypol, corresponding to about 40 times IC50. However, incubation with low gossypol concentrations markedly affected the energetic status of the cells, especially of the TM3 cells. Although inhibition of proliferation by gossypol was stronger with the TM4 cells, the decrease of intracellular ATP level and increase of sodium ion concentration were more pronounced in the TM3 cells. The growth-inhibitory effect of (-)-gossypol was stronger than that of (+)-gossypol, with the eudesmic ratio of 2-2.5. The enantioselectivity of the effect of gossypol on the energy metabolism of TM3 and TM4 cells was low, in contrast to the in vivo antispermatogenic effect, which was reported to be solely associated with (-)-gossypol. Inhibition of energy production in somatic testicular tissue is thus unlikely to be major cause of the antispermatogenic effect of gossypol.

Genetic toxicity studies of gossypol

Gossypol, a polyphenolic compound extracted from cotton plants, shows promise for use as a male contraceptive, as well as a treatment for gynecological disorders, cancer, and certain microbial diseases. Before gossypol can be considered safe for widespread human use, particularly by healthy people of childbearing age, its effect on normal genetic processes should be understood. Characterization of gossypol's genotoxic potential has not been approached systematically, although numerous clinical and laboratory studies have addressed issues relating to genetic effects of gossypol. This review summarizes results of relevant studies and offers recommendations for the emphasis of future efforts to understand gossypol's genotoxicity potential. Evidence suggesting that gossypol has any genotoxic effects in mammals under normal physiologic conditions so far is weak, at best. However, several unresolved issues that are important for establishing long-term genetic safety of gossypol were uncovered by this analysis. These include the need for a better understanding of the significance of weak increases in SCE frequency seen in a number of laboratory exposure studies, and more definitive, comprehensive animal tumor bioassay data.