Modulatory effect of cashew (Anacardium occidentale L.) nut supplemented diet on fertility activity of clomiphene citrate in male rats
Main article: Treatment of Low Sperm Count
doi.org/10.1016/j.bj.2019.12.005
Background
A variety of medications is commonly used to improve sperm quality and subsequently enhance male fertility. This includes follicle stimulating hormone (FSH), anti-estrogens, L-carnitine and antioxidants.
In males with low levels of testosterone, the anti-estrogen clomiphene citrate, is regularly prescribed. This causes an increase in serum levels of LH (luteinizing hormone) and FSH, which in turn increases testosterone and sperm production within the testes.
In more traditional medicine, cashew nuts is commonly referenced as an aphrodisiac and cure for impotency. Cashew nuts are naturally high in Zinc, an essential mineral for proper sperm motility and production, with short term deficiency impacting testosterone levels and sperm volume.
Although both clomiphene citrate and cashew nuts individually enhance male fertility, there has been no studies to date on the combined effects.
Methodology
In his controlled study, a total of 36 adult male rats was randomly allocated into 6 even groups;
Group 1 – 100g basal diet (control)
Group 2 – 100g basal diet and clomiphene citrate
Group 3 – 90g basal diet, 10g cashew nut and clomiphene citrate
Group 4 – 80g basal diet, 20g cashew nut and clomiphene citrate
Group 5 – 90g basal diet and 10g cashew nut
Group 6 – 80g basal diet and 20g cashew nut
Duration of treatment was 14 days with epidydimal sperm count, morphology, motility and viability analysed. Similarly total thiol and non protein thiol levels was also measured, along with total antioxidant capacity, lipid peroxidation, reactive oxygen species, nitric oxide, arginase, Glutathione-S-transferase and steroidogenic enzymes 3β and 17β-hydroxysteroid dehydrogenase (HSD), to comprehensively interpret the results.
Results
Initial analysis revealed a significant increase in the epidydimal sperm count, viability and motility in the treated groups with a simultaneous decrease in abnormal sperm levels. Interestingly the increase in the combined treatment group featuring both cashew nuts and clomiphene citrate was more significant than either cashew nuts or clomiphene citrate alone.
| Group | Sperm count (106) | Viability (%) | Motility (%) | Abnormality (%) | Testosterone (ng/gl) |
| 1 | 15.5 | 34.4 | 20.5 | 16.8 | 16.3 |
| 2 | 20.3 | 40.0 | 30.5 | 8.4 | 30.6 |
| 3 | 32.2 | 46.0 | 38.1 | 5.4 | 34.8 |
| 4 | 25.5 | 49.0 | 39.8 | 5.2 | 43.0 |
| 5 | 17.3 | 38.1 | 28.4 | 11.7 | 18.4 |
| 6 | 19.5 | 39.8 | 29.9 | 10.8 | 28.5 |
Testosterone and testicular steroidogenic enzymes were also significantly elevated in the treatment groups, although this was more pronounce in the combined treatment groups, with Group 4, consisting of 20g cashew nut and clomiphene citrate, showing a doubling of 3β-HSD and 17β-HSD levels and 160% increase in testosterone. On the other hand Group 6, consisting of only 20g cashew nut, increased 3β-HSD and 17β-HSD levels by approximately 30% and testosterone by 75%.
| Group | Testis 3β-HSD | Testis 17β-HSD | NO Testis | NO Epididymis | Testis Arginase | Epididymis Arginase |
| 1 | 18 | 16 | 11 | 17 | 44 | 50 |
| 2 | 27 | 21 | 20 | 42 | 25 | 38 |
| 3 | 36 | 28 | 30 | 45 | 20 | 30 |
| 4 | 40 | 31 | 30 | 52 | 21 | 26 |
| 5 | 24 | 19 | 11 | 23 | 39 | 50 |
| 6 | 25 | 21 | 13 | 24 | 31 | 41 |
| Units | units / mgprotein | units / mgprotein | nMolNOx / mgprotein | nMolNOx / mgprotein | μmol / mgprotein / min | μmol / mgprotein / min |
Similarly nitric oxide (NO), which plays a role in the production of superoxide anion and manages free radicals, was significantly increased in the combined treatment groups featuring clomiphene citrate, in both the testis and epididymis, while the basal diet plus cashew nut groups only significantly increased nitric oxide levels in the epididymis. Coincidentally arginase which is involved in the nitric oxide/cyclic guanidine monophosphate pathway, showed proportionate decrease in levels, confirming the findings of previous studies showing that arginase and nitric oxide synthase compete with each other for L-arginine, and therefore influence nitric oxide production.
| Group | Testis T-SH | Epididymis T-SH | Testis GSH | Epididymis GSH | Testis TAC | Epididymis TAC |
| 1 | 10 | 9 | 8 | 10 | 21 | 17 |
| 2 | 19 | 19 | 16 | 24 | 30 | 27 |
| 3 | 23 | 36 | 18 | 25 | 34 | 37 |
| 4 | 38 | 37 | 18 | 35 | 34 | 37 |
| 5 | 13 | 9 | 9 | 11 | 22 | 24 |
| 6 | 16 | 18 | 9 | 18 | 24 | 21 |
| Units | μmol / mgprotein | μmol / mgprotein | μmol / mgprotein | μmol / mgprotein | μmol / mgprotein | μmol / mgprotein |
Next antioxidant indicators; total thiol (T-SH), reduced glutathione (GSH), total antioxidant capacity (TAC), glutathione-S-transferase (GST), reactive oxygen species (ROS) and thiobarbituric acid reactive substances (TBARS) showed similar improvements, with the combined treatment of clomiphene citrate and cashew nuts having the largest effect, while the basal diet and cashew nut treatment only showed significantly consistent improvements in the epididymis results. Overall the addition of cashew nuts to clomiphene citrate caused a ‘synergistic effect’ on all antioxidant indicators, which may be a result of the phenolic compounds found in cashew nuts.
| Group | Testis GST | Epididymis GST | Testis ROS | Epididymis ROS | Testis TBARS | Epididymis TBARS |
| 1 | 48 | 48 | 62 | 33 | 21 | 19 |
| 2 | 28 | 35 | 29 | 19 | 12 | 6 |
| 3 | 27 | 34 | 24 | 10 | 8 | 6 |
| 4 | 20 | 21 | 23 | 15 | 7 | 5 |
| 5 | 40 | 45 | 48 | 30 | 16 | 11 |
| 6 | 34 | 41 | 32 | 24 | 12 | 9 |
| Units | μmol CDNB-GSH / min / mgprotein | μmol CDNB-GSH / min / mgprotein | U / mgprotein | U / mgprotein | μmol.MDA / mgprotein | μmol. / mgprotein |
Interestingly histological examination of the testis showed no visibly significant difference in the structure of seminiferous tubules between the groups although the authors did note that the tissue samples from the combined treatment groups (Group 3 and 4) were more comparable to the control group.
SUMMARY: GOOD NUTS FOR SPERM COUNT
In this study, 10% dietary intake of cashew nuts caused a significant increase in sperm count (12%), viability (11%) and motility (39%) levels, and a decrease in sperm abnormality levels, explained by significantly increased testosterone (13%) and antioxidant levels.
Limitations
- Male rat spermatogenesis is close however not identical to humans
- Treatment period shorter than duration of rat spermatogenesis
Funding
No external funding was declared for this study.
Glossary
17β-hydroxysteroid dehydrogenase
A critical enzyme involved in the production of testosterone from androstenedione.
3β-hydroxysteroid dehydrogenase
A critical enzyme involved in the production of progesterone, 17α-hydroxyprogesterone, testosterone, androstenedione and androstadienone.
Arginase
A regulator of oxidative stress.
Epididymis
A highly convoluted duct behind the testis, along which sperm passes to the vas deferens.
Glutathione-S-transferase
An enzyme which quenches reactive molecules with the addition of glutathione (GSH) to protect cells from oxidative damage.
Histological
The study of the structure of cells and tissue under a microscope.
Lipid peroxidation
Oxidative damage caused by free radicals upon unsaturated fatty acids in cell membranes.
Nitric oxide
A free radical leading to oxidative stress.
Non protein thiol
All low molecular weight thiol-compounds containing a sulfhydryl group (-SH) in their structure.
Reactive oxygen species
Highly reactive chemicals formed from O2.
Seminiferous tubules
The site where sperm is produced within the testes.
Thiobarbituric acid reactive substance
A common method by which to measure lipid peroxidation.
Total thiol
The main plasma antioxidants in the body.
Similar studies
Bharti S, et al. (2013). Clomiphene citrate potentiates the adverse effects of estrogen on rat testis and down-regulates the expression of steroidogenic enzyme genes. https://doi.org/10.1016/j.fertnstert.2012.08.050
Mbatchou V C and Kosoono I, (2011). Aphrodisiac activity of oils from Anacardium occidentale L. seeds and seed shells. http://inforesights.com/phytopharmacology/files/pp2v7.pdf
Patankar S S, et al. (2007). Effect of clomiphene citrate on sperm density in male partners of infertile couples. https://pubmed.ncbi.nlm.nih.gov/18175667/
WHO, (1992). A double‐blind trial of clomiphene citrate for the treatment of idiopathic male infertility. https://doi.org/10.1111/j.1365-2605.1992.tb01129.x
fertilPEDIA
Low sperm count, also known as oligospermia or oligozoospermia, happens when a man has 15 million or less sperm per millilitre (mL) of…. Read more
Unexplained infertility is defined as the failure to conceive after 12 months of regular unprotected sexual intercourse and no identifiable cause following…. Read more