Anti-Fertility Effects and Mechanism of the Plant Extract Shikonin on Mice

Controlling fertility of rodent pests has become an effective means of controlling the population of grassland rodents in China. Recently, research has focused on how to select environmentally-friendly sterilants without pollution effects, and to realize sustainable control of pest rodent populations. Sterilants from plant extracts have been mainly selected. In this study, mice were used as the experimental subjects for research on the anti-fertility effects of plant extracts of shikonin and the anti-fertility mechanism of shikonin extract was determined. The mice were divided into four groups, including one control group and three experimental groups. There were three applications of shikonin extract in different concentrations (5 mg·kg-1, 20 mg·kg-1 and 50 mg·kg-1). The mice gavage experiments indicated that a shikonin concentration of 50 mg·kg-1 had the expected anti-fertility effects. Mice copulation experiments showed that the 50 mg·kg-1 shikonin treatment had significant anti-fertility effects on both female-treatment and female-male-treatment groups. The results of the PCR analysis on the AgRP and ghrelin mRNA from female ovaries and male testicles indicated that shikonin could control mice reproduction by regulating the pituitary gonadal axis. Shikonin, as plant source sterile agent, would have more ideal effects for functioned both sexes sterility.

Antifertility effect of chronically administered Tabernaemontana divaricata leaf extract on male rats

Objective:To investigate the antifertility effect of chronically administered Tabernaemontana divarkala(T.divaricata) leaf extract on male rats.Methods:The effect of 50%ethanol extract of T.divaricata leaves on reproduction was studied on male rats.The study was divided into four groups of five animals each.The first groups(1) received vehicle alone to serve as control. The second,third and fourth groups(Ⅱ,ⅡandⅣ) of animals were administered the leaf extract daily at 50 mg/kg body weight,p.o.,100 nig/kg body weight,p.o.,and 200 mg/kg body weight, p.o.,respectively,for a period of 60 days.Results:Significant decreases in the weight of testes, epididymis,seminal vesicle and ventral prostate were observed.A dose related reduction in the testicular sperm count,epididymal sperm count and motility,number of fertile male,ratio between delivered and inseminated females and numbers of pups were observed.The testis showed a clear correlation between the dose and severity of lesions of seminiferous epithelium. In general,the seminiferous tubules appear reduced in size with a frequently filled eosinophilic material.Spermatogenesis arrested at the secondary spermatocyte stage.Pachytene spermatocytes were undergoing degeneration.Disorganisation and sloughing of immature germ cell were visible. Leydinf cells were atrophied.No morphological changes were observed in Sertoli cells.Significant reduction in serum concentration of luteinizing hormone and testosterone were observed.No distinct change in serum FSH concentration was recorded.The final body weights of all groups were elevated markedly.No alterations were recorded in any hematologiocal parameters. Conclusions:It is concluded that the 50%ethanol extract of T.divaricata leaf produced dose related effect on male reproduction without altering general bodv metabolism.

Studies on Male Antifertilitic and Immunomodulatory Effects of TW19

TW19 is a diterpene compound isolated from the root cortex of Tripterygium Wil- fordii Hood. F.. Its effects on the immune function in ICR mice and the male fertility in SD rats, ICR mice and Kunming mice were evaluated. TW19 was given orally for 5 weeks. Then the antifertilitic effect was assessed by mating test. The results showed that ED50, for anti-fertilitic were 332μg/kg, 369. 9μg/kg and 286. 8 μg/kg per day in SD rats, ICR mice and Kunming mice respectively. After the treatment of TW19 at antifertility dose for 5 weeks consecutively, the spermatozoa density and motility of trial animals reduced significantly, The weight of testic also declined in SD rats and Kunming mice, but no effects were observed in ICR mice. TW19 inhibited prolifera- tion of splenic T and B-lymphocytes of ICR mice in vitro and hence inhibited the anti- body formation in vivo, but compared with T 4, the immunosuppressive effect of TW19 was less obvious.

Biodegradable implants based on photo-cross-linked aliphatic polycarbonates for long-acting contraception

In this study,a new class of biodegradable contraceptive implants was prepared via the UV irradiation molding method,among which,progestin levonorgestrel(LNG)was used as a model drug.Photo-cross-linked aliphatic polycarbonates(APCs),namely,poly(trimethylene carbonate-co-2,2′-dimethyltrimethylene carbonate)[P(TMC-co-DTC)]elastomers,were used as the drug delivery matrix.The results obtained from the degradation experiments carried out in Sprague-Dawley(SD)rats showed that the cross-linked elastomer had the degradation characteristics of the surface erosion degradation mechanism,with no generation of acid degradation products,and excellent form-stability,which met the performance requirements of the matrix for a long-acting sustained-release delivery system.The in vitro cytotoxicity tests and histological and immunohistochemical evaluations showed good biocompatibility and biosafety of the elastomer matrix material and contraceptive implants.Subsequently,the implant formulations were screened by in vitro release experiments,and their release kinetics were explored.Finally,in the evaluation study of the in vivo anti-fertility effect,the implants exhibited excellent dimensional stability and were degraded by a surface erosion mechanism.LNG achieved a stable and sustained release in female SD rats,maintaining a long-acting contraceptive duration of up to 4 months.The contraceptive implants obtained in this study could be used to address the limitations of currently available formulations,which required secondary surgical removal and a single means of regulating drug release kinetics.Therefore,these implants could provide a new option for birth control needs and may be of significance in reducing the incidence of induced abortion and protecting female fertility.

Assessment of non-target toxicity effects of synthetic estradiol, quinestrol, in chickens

Fertility control agents for the management of rodent populations are developing and maturing.Investigating the impacts on non-target species of consumption of these agents is essential.The present study assessed the non-target toxicity effects of quinestrol,a synthetic estrogen-based antifertility agent for managing rodent populations.Various quinestrol doses administered to male and female(n=60 each)chickens through single oral gavage were 0(A),10(B),50(C),and 150(D)mg/kg body weight.Chickens were assessed for effect on body weight,weight of vital and reproductive organs,reproductive hormones,histology of reproductive organs and egg laying rates after 15,30,and 135 days of treatment.Quinestrol did not induce mortality in chickens and its effects were time and dose dependent.The 90%egg-laying rates were delayed by 30,60 for groups B and C compared with the control group,and group D did not reach the 90%egg-laying rate by 135 days.Reproductive organs in males and females returned to normal levels within 30 and 135 days,respectively.With the exception of the FSH concentration in group D,reproductive hormones of both sexes were similar to controls by 30 days.No other significant effects were found.The present research demonstrated the safety of quinestrol on non-target species and facilitates recommendations for the general administration of quinestrol for rodent pest management.