Improvement of sperm density in neem-oil induced infertile male albino rats by Ipomoea digitata Linn.

AIM: Investigation has been carried out to validate folkloric claim of the potential of Ipomoea digitata (ID) based on reproductive health status in experimentally induced male albino rats.
MATERIALS AND METHODS: Emulsified neem oil fed albino rats were orally administered root powder of ID suspended in water for the doses of 250 and 500 mg/kg body weight for 40 days. Change in organ weight, sperm density and motility, serum hormonal levels and histomorphological changes were evaluated.
RESULTS: Significant increase in the sperm density and the sperm motility (P < 0.01) along with increase in the testis, and epididymes weight in neem-oil induced infertile rats treated with ID at both dose levels. This effect is vis-à-vis to serum hormonal levels. Presence of β-sitosterol in the root of ID likely to enhance the process of spermatogenesis as it is evident from histomorphological studies.
CONCLUSION: Results of the present investigation reveal that ID is a good candidate for the management of male infertility.

INTRODUCTION

Ipomoea digitata Linn. (ID) is a well-known medicinal plant used in Ayurveda for its health promoting effects. ID, a member of family Convolvulaceae is known as Ksheera-vidaari, Ksheervalli, Payasvini, Swaadukandaa, Ikshukandaa, Gajavaajipriyaa, Kandapalaasha, Bhuumikuushmaanda in Sanskrit; Bilai-khand, Bidarikand in Hindi; Bhui-kohala, Pattana in Marathi and Gujarati; Bhumikumra, Bhuikumra in Bengali; Matta-paltiga, Nelagummudu in Telugu; Phalmodika, Nelli-kumbala in Tamil; Mothalkanta, Palmodikka in Malyalam and Milky Yam in English. Its synonyms are Ipomoea paniculata (R.Br.); Convolvus paniculata (Linn.); Batatas paniculata (Choisy) and Ipomoea mauritiana (Jacq.). Ayurveda described it in Bhav-Prakash Nighantu as, [1].

Root is a tonic, alternative, aphrodisiac, demulcent, galactagogue, mucilaginous and has a bitter taste [2]. Flour of raw rhizome of this plant is given in enlargement of liver and spleen, also for menorrhagia, debility and fat accumulation [3]. The tuberous root of ID bend with other plants part used in spermatorrhea. Aphrodisiac activity of tuberous root of ID was documented earlier [4]. Tuberous root contains a resin (similar to Jalap resin), sugar, principally starch and β-sitosterol. Carbohydrates, glycosides, proteins and amino acids, saponins, alkaloids, flavonoids, phytosterol, gum and mucilage are present in the aqueous extract of tuberous root [5]. Primary and secondary metabolites except saponins in root powder of ID were also reported [6].

Low sperm density and motility are major causes of male infertility. Common male infertility factors include azoospermia (no sperm cells are produced except obstructive azoospermia), asthenozoospermia (decreased motility of sperm) and oligozoospermia (few sperm cells are produced) [7]. A number of researchers focused this issue for establishing the appropriate reason for declination in sperm density and seminal volume worldwide in last five decades [8,9]. Sperm produce controlled concentration of reactive oxygen species (ROS), such as superoxide anion, hydrogen peroxide and nitric oxide, which are needed for fertilization. However high concentrations of these free radicals can directly damage sperm cells and ultimately decline sperm density [10-12]. High levels of ROS in semen have been correlated with reduced sperm motility and damage to sperm nuclear DNA [13].

Medicinal plants play an important role in the development of potent therapeutic agents. Plant derived drugs came into use in the modern medicine through the uses of plant material as indigenous cure in folklore or traditional systems of medicine [14]. Inadequate information is available about the ID in the literature regarding use of its root to elevate sperm density in experimental animals. Therefore, in the present study an indigenous medicinal plant, ID was investigated for its use in increasing sperm density.

MATERIALS AND METHODS

Plant Material and Authentication

In the present study, ID was collected from Satpura ranges and authenticated at the Department of Botany, SSVPS College, Dhule (Maharashtra). Filtered neem oil was bought from the local market.

Animals

Healthy, sexually mature male and female white albino rats (Rattus norvegicus) weighing between 240 and 260 g were selected. They were kept in a well-ventilated animal house and fed with commercial rat feed purchased from Prashant traders, Pune (Maharashtra) India. They were allowed unrestricted access to clean tap water ad libitum.

Preparation of Root Powder

Tuberous root of ID [Figure 1] was sliced and dried under shed. The dried pieces were then pulverized using an electric blender. The powdered material stocked in a plastic container.

Figure 1

Sliced Ipomoea digitata root

Selection of Animals, Grouping and Treatment

Sexually mature two female rats and one male albino rat were placed in one cage. Presence of vaginal plug was taken as the day one of pregnancy. The females allowed to delivered pups and pups were counted and observed their growth. Such male rat is identified and considered fertile. Thus they were selected for this experimentation. Twenty-four proved fertile male rats were divided into four groups. Each group contains six rats. Group I (control group) animals, received 5 ml of the “vehicle” (distilled water). Group II animals, received emulsified neem oil (ENO) (ENO 0.5 ml + 4.5 ml Distilled water) for 15 days. Group III and Group IV animals, received ENO for 15 days and a day gap were treated with ID root powder suspended in water twice daily at the dose of 250 mg/kg and 500 mg/kg body weight respectively for 40 days using feeding needle. Experimental rats were allowed free access to rat feed and tap water ad libitum. All the animal experimentation was carried out under the guidelines of Institutional Animal Ethical Committee (IAEC) of CPCSEA, India. (No: IAEC/08/CPCSEA/MJ/2010).

Experimentation

The day after their daily doses for 15 and 55 days for Groups II and III to IV, the blood was collected from the retro-orbital plexus after treatment. After clotting of blood, the serum was collected and stored at 8°C in refrigerator. Experimental rats were dissected. The epididymes were separated from the testes by blunt dissection. They were weighed separately. The epididymes were cut open longitudinally and with gentle pressure on the serosa, a drop of semen was expressed on a pre-warmed slide (37°C). A drop of 2.9% sodium citrate buffer was added to the expressed semen drop and cover-slip was applied to evaluate motility under ×40 of microscope. Semen examinations were done using methods described by Zemjanis [15]. Following separation of the epididymes, the testicles were fixed in 10% formaldehyde saline in labeled bottles and processed routinely for histological examinations. This was later observed using Olympus (model-41) research microscope at ×40, ×100 and photomicrographs were taken. The serum testosterone, luteinizing hormone (LH) and follicle stimulating hormone (FSH) were determined on the VIDAS instrument using the enzyme linked fluorescent assay kits of BioMerieux (France) according to the methods of Wide, Bardin and Butt [16-18].

Statistical Analysis

The treated groups were compared to control by One-way ANOVA with Dunnett’s post-test was performed using GraphPad Prism Demo version 4.00 for Windows, GraphPad Software, San Diego California USA, was used. Differences were considered significantly when P < 0.05.

RESULTS

Treatment with ENO to male albino rats (Group-II) for 15 days, a significant reduction was seen in almost all the parameters viz. testes and epididymes weight [Figure 2], sperm density and motility, serum levels of testosterone, FSH and LH compared with control group rats. Previous studies on acute toxicity of ID allowed us to take the dose levels of 250 and 500 mg/kg body weight (b.w) [5,19].

Figure 2

Regain in reproductive organs weight (g) of male albino rats. X-axis represents weight and Y-axis represents treatment groups

Treatment with ID (Group III and IV) at both doses to male albino rats for 40 days results in the significant increase in all the parameters viz. testes and epididymes weight [Figure 2]; sperm density and sperm motility; serum levels of testosterone, FSH and LH compared with control group rats. Change (%) was calculated and shown in [Table 1].

Table 1

Regain in sperm density, motility and serum hormonal levels of male albino rats

Testis of albino rat treated with ENO shows arrest of spermatogenesis, derangement of germinal epithelial along with blood clotting [Figure 3]. Testis of albino rat treated with ID shows spermatozoa and sperm bundle illustrates restoration of the process of spermatogenesis [Figure 4].

Figure 3

Photomicrograph of testis treated with ENO shows arrest of spermatogenesis (AS), derangement of germinal epithelium (DGE) with blood clotting (BC). Five microns tissue sections stained with hematoxylin and eosin

Figure 4

Photomicrograph of testis treated with ID shows restoration of the process of spermatogenesis. Tissue sections stained with hematoxylin and eosin. S: Spermatogonia; SS: Secondary spermatocyte; ST: Spermatid; SZ: Spermatozoa; GE: Germinal Epithelium and L: Leydig cells.

DISCUSSION

Long term anti-fertility effect of neem oil was noted in rats [20]. Our findings in neem oil treated group evaluate the reduction in sperm density and motility was resulted due to arrest of spermatogenesis. Decrease in sperm volume, sperm motility and serum testosterone level after administration of Azadirachta indica stem bark extract was also observed in rat [21]. Histopathological studies showed changes like disruption to spermatogenesis in some seminiferous tubules included derangement of the first layer of spermatogonial cells and necrotic spermatocytes of male rats treated with commercial neem (A. indica Juss) extract for 25 days [22]. These results are in accordance with our findings [Figure 3]. Albino rats treated with ENO for 15 days subsequently with ID showed high degree of integrity of Leydig cells with seminiferous tubules having spermatogonia, primary and secondary spermatocytes, Sertoli cells along with nucleus and bunches of maturing late spermatids [Figure 4]. Spermatozoa and sperm bundles in the lumen of seminiferous tubules are the evident of the restoration of the process of spermatogenesis. It has been postulated, however, that reproductive organ weight and function such as testes, epididymes and seminal vesicles, are closely regulated by androgens [23]. Improvement in body weight is generally attributed to steroid genesis and is a biological indicator for effectiveness of the herbal drugs in improving the genesis of steroidal hormones [24]. It was assumed that ID possesses progenitors of testosterone biosynthesis because of the presence of β-sitosterol in the roots, which was confirmed in our laboratory using high performance thin layer chromatography. It is evident from our findings that rats treated with ID at both doses attributed increase in sperm density and testosterone which established a reciprocal relation.

Numerous studies demonstrates that ID possesses moderate antioxidant potential which may be due to the presence of phenolic compounds, coumarins, flavonoids and steroids [6,25,26]. Overproduction of ROS can lead to a state of oxidative stress that compromises sperm function [27]. ROS are neutralized by an elaborate antioxidant system consisting of enzymes such as catalase, superoxide dismutase and glutathione peroxidase/reductase, and numerous non-enzymatic antioxidants such as vitamin C, vitamin E, vitamin A, pyruvate, glutathione, taurine and hypotaurine. The male and female genital tracts are rich in both enzymatic and non-enzymatic antioxidants [28,29]. We have a strong assumption that the phytochemicals present in the said plant are capable of synthesizes the ROS scavengers in infertile male albino rats particularly to repair the oxidative damage of spermatozoon characteristics. Rats treated with ID at the dose of 500 mg/kg b.w. exhibits more penile erections lead to establishment of physiological and biochemical mechanisms remain uncertain. In nutshell, ID has spermatogenic activity along with anabolic effect in experimental rats.