Testicular toxicity of methylmercury: analysis of cellular distribution pattern at different stages of the seminiferous epithelium

Stage-specific distribution of methylmercury (MM) and spermatogenic changes were analyzed in rats administered 5 or 10 micrograms MM/kg, ip, daily for 15, 30, 60, and 90 days. MM deposition, as grain number/cm2 was noted in basal portions at later stages on day 15, which increased gradually by day 90. MM deposition was in the order of stages IV, VII, XIV, IX, being higher in adluminal portions on days 30 and 60. MM-enriched cytoplasmic masses leaked out through disintegrated tubular membrane on days 60 and 90. Epithelial damage, at stages late XIV through IV, V through VI, VII through VIII, XIII through mid-XIV, and IX through XII, accorded with the gradual deposition of MM. As profound cell death occurred between zygotenes to pachytenes and dividing spermatocytes to step 1 spermatids, the spermatids were conspicuously decreased at later times. It is possible that MM distorts the barrier system at stages IX through XII, gets distributed within the tubule, and hence may pose a direct or Sertoli cell mediated effect at stages XII through early XIV in a dose-duration-MM burden related manner.

Steroidogenic inhibition in testicular tissue of formaldehyde exposed rats

Three groups of rats (n = 10) were subjected to intraperitoneal treatment of formaldehyde daily at doses of 5, 10 and 15 mg/kg body weight over a period of 30 days. Gradual diminution in body and testicular weight was observed in all treated groups. Leyding cell impairement was conspicuous in those given doses of 10 and 15 mg/kg. Inhibition of 3 beta-delta 5-hydroxy steroid dehydrogenase and accumulation of sudanophillic materials in testicular tissue of formaldehyde treated rats was recorded histochemically. Significant decline of serum testosterone was also observed in the same groups. Structural and functional impairement of Leydig cells after formaldehyde treatment caused steroidogenic inhibition.

Distribution of mercury and evaluation of testicular steroidogenesis in mercuric chloride and methylmercury administered rats

Intraperitoneal administration of methylmercury chloride (MMC) and mercuric chloride (MC) to male rats in doses of 5, 10 micrograms MMC/kg or 50, 100 micrograms MC/kg for 90 days induced cellular disintegration of Leydig cells which was conspicuous on day 30 and onwards in the exposed groups. Progressive degeneration of Leydig cells and decrease in their nuclear diameter and population were associated with gradual increase in deposition of mercury. Gradual diminution of 3 beta-hydroxy-delta 5-steroid dehydrogenase activity in Leydig cells after MMC or MC treatment was correlated with different structural deformations of the cells over 90 days. Moreover, a significant decrease in serum testosterone levels by day 90 confirmed steroidogenic impairment after MMC or MC treatment.

BHC induced testicular impairments in rats

Benzene hexachloride (BHC) was fed to mature male rats weighing 160 g at dosages of 3 and 6 mg/kg body weight over a period of 180 days. Significant decrease in testicular weight and degeneration of seminiferous tubules with deformed spermatogenic cells were noted at a dose of 6 mg/kg BHC. Marked increase in BHC residue in testis revealed that the drug was able to cross blood-testis barrier.

Methylmercury induced biochemical and histochemical alterations in rat testis

The methylmercurry chloride (MMC) administered at doses of 5 and 10 micrograms/kg over a period of 90 days to male rats caused enzymatic impairments in testicular tissue. The study at intervals of 15, 30, 60 and 90 days showed gradual diminution of testicular weight and gradual decrements in testicular protein and inhibition in testicular succinic dehydrogenase activity. Histochemical and biochemical studies revealed that testicular acid phosphatase activity was also inhibited at both the doses of MMC treatment. The inhibition of enzyme activity in testicular tissues after MMC treatment caused the impairment of both spermatogenesis and steroidogenesis in rats.

Methylmercury- and mercuric-chloride-induced alterations in rat epididymal sperm

Four-week-old male albino rats weighing 70 +/- 5 g were treated intraperitoneally daily with 0, 5 and 10 micrograms methylmercuric chloride (MMC)/kg or 0, 50 and 100 micrograms mercuric chloride (MC)/kg body weight, respectively, over a period of 90 days. Studies were carried out a intermittent intervals, i.e. on days 0, 15, 30, 60 and 90 of the experiment. Gradual decrements in body and epididymal weights were observed from day 30 onwards in both the MMC- and MC-treated groups. Morphological deformations of epididymal epithelium were noted from day 30 onwards in the mercurial-treated groups. MMC treatment caused severe degeneration of the epididymal epithelium on days 60 and 90 in comparison to MC treatment. Total sperm count was significantly less in the MC-treated groups, while motile sperm count was affected most in the MMC-administered groups. The frequency of sperm abnormality increased consistently at both doses of mercurial treatment over a period of 90 days. Maximum sperm abnormality among the treated groups was noted in the groups given 10 micrograms MMC/kg. The observations revealed that MMC and MC have variable potency to alter epididymal structure and the sperm.

Histological and pharmacological changes in vas deferens of rats exposed to hexachlorocyclohexane

The effect of hexachlorocyclohexane (HCH) treatment in male albino rats at dosages of 3 and 6 mg/kg body weight by force-feeding were studied over a period of 180 days. Histological observations revealed graded degeneration in the muscular layer of vas deferens. Moreover, the accumulation of HCH residue in serum and vas deferens is highly significant in the experimental group. The contractility of muscles showed marked inhibition by in vitro study.

Trace elements in the endometrium of infertile women

Some essential trace elements were estimated in endometrium of regularly menstruating fertile women and in women with infertility due to cervical factors. The distribution of the trace elements zinc, copper, iron, selenium and manganese at any particular phase of cycle remains more or less semilier between control (i.e. fertile) and infertile (primary and secondary) subjects.

The infant mortality-fertility debate: some international evidence

"The aim of this paper is to analyze empirically the causal relationship, if any, between infant mortality and fertility in thirty-five developing countries." The focus is on possible relationships between the infant mortality rate and the fertility rate. "The hypothesis that infant mortality causes fertility is tested. The possibility of a 'reverse causation' is also analyzed. A one-sided distributed lag test as proposed by Granger...is employed." The results are analyzed in light of several versions of the mortality-fertility proposition, including demographic transition theory, choice theory, Ricardian theory, and the modern economic theory of population.

Effect of lead on erythropoietic system of intact and splenectomized rats

Erythropoietic alterations in normal and splenectomized mature male rats treated with aqueous lead acetate intraperitoneally at dosages of 4 mg/kg and 6 mg/kg body weight were observed over a period of 30 days. Significant retardation in growth might be due to gradual increases in lead toxicity. The elevated blood lead level, increased urinary delta-amino-levulinic acid (ALA-U) excretion, depletion in RBC and haemoglobin content and more number of reticulocytes in peripheral blood indicated the increased intensity of lead toxicity and inhibitory effect on haem biosynthesis. The accelerating action of lead on erythropoietic cellular series i.e. pronormoblast, early and intermediate normoblast and late normoblast was evident by the significant increase in number of cellular count both in intact and splenectomized rats after treatment with lead.

Testicular regulation and sub-cellular distribution of zinc in the epididymis and vas deferens of rhesus monkey (Macaca mulatta)

The zinc concentration in the epididymis (caput, corpus and cauda regions), vas deferens and caudal lobe of prostate of adult rhesus monkeys was determined by atomic absorption spectrophotometry. Zinc content (microgram/g wet weight) was found to be maximum in the prostate (709 micrograms) followed by epididymis and vas deferens. The three segments of the epididymis did not differ from one another in their zinc content (165-177 micrograms). On a protein basis maximum concentration of zinc was present in the nuclear fraction followed by microsomal, cytosolic and mitochondrial fractions in that order. Ligation of testicular efferent ducts or castration 90 days prior to autopsy caused a marked reduction in zinc concentration in different sub-cellular fractions of the organs examined; castration was relatively more effective in this regard. The importance of androgen and other testicular products in controlling zinc content and the possible physiological role of zinc in the male genital tract are discussed.

Effect of lead on human semen

Semen qualities were studied in workers with an average age of 30 years and occupationally exposed to lead in a printing press. Another sample with the same average age but not exposed to lead were taken as control subjects. The average lead content in blood and seminal plasma of the exposed group were 42.5 mcg/100 ml and 14.80 mcg/100 ml, respectively. Their sperm counts and percentage of motile sperm were significantly affected. Significantly higher percentages of abnormal spermatozoa were also observed in these semen samples. The levels of seminal acid phosphatase, succinic dehydrogenase, and fructose in them were also significantly found to be low compared with those from the unexposed subjects. Cytochemical study of sperm head DNA in the exposed groups showed a low surface reaction.