Morphological changes in spleen after dietary zinc deficiency and supplementation in Wistar rats.

BACKGROUND: Study was conducted to determine the effect of dietary zinc deficiency and supplementation on the spleen morphology. METHODS: Pre-pubertal Wistar rats (40-50 g) were divided into two groups with 6 sub-groups each viz. zinc control (ZC, 100 µg/g zinc diet), pair fed (PF, 100 µg/g zinc diet), zinc deficient (ZD, <1 µg/g zinc diet, zinc supplementation control (ZCS), zinc supplementation pair-fed (PFS) and zinc supplementation deficient (ZDS, 100 µg/g zinc control diet). Experiments were set for 2- and 4-weeks followed by 4 weeks of zinc supplementation. RESULTS: In the present study body weight and BMI decreased significantly along with incidence of splenomegaly as typified by the increased splenic index in deficient groups compared with that of respective control groups. Histopathological changes such as disorganization of red pulp, several infiltered lymphocytes, vacuolization, loss of cellularity, karyolysis, dissolution of matrix, indistinct differentiation between red and white pulp were evident in spleen of 2ZD and 4ZD group animals. Degeneration was more severe after 4 weeks of zinc deficiency as giant cells formation and hypertrophy were also evident. CONCLUSION: The findings revealed that zinc deficiency causes growth retardation and splenomegaly. Degenerative and atrophic changes in rat spleen suggest reduced cellular defense potential which will have a direct effect on immunity. Zinc supplementation may prove to be beneficial as there were varying degrees of cellular recovery after cessation of zinc deficiency.

Dietary zinc deficiency effects dorso-lateral and ventral prostate of Wistar rats: histological, biochemical and trace element study.

Zinc deficiency has become a global problem affecting the developed and developing countries due to inhibitors in the diet which prevents its absorption or due to a very low concentration of bioavailable zinc in the diet. Being present in high concentration in the prostate and having diverse biological function, we investigated the effects of dietary zinc deficiency for 2 and 4 weeks on dorso-lateral and ventral prostate. Sixty prepubertal rats were divided into three groups: zinc control (ZC), pair fed (PF) and zinc deficient (ZD) and fed on 100 µg/g (zinc control and pair fed groups) and 1 µg/g (zinc deficient) diet. Zinc deficiency was associated with degenerative changes in dorso-lateral and ventral prostate as made evident by karyolysis, karyorhexis, cytoplasmolysis, loss of cellularisation, decreased intraluminar secretion and degeneration of fibromuscular stroma. In response, protein carbonyl, nitric oxide, acid phosphatase, 3ß-hydroxysteroid dehydrogenase and 17ß-hydroxysteroid dehydrogenase increased, exhibiting variable level of significance. Total protein and total zinc concentration in dorso-lateral and ventral prostate as well as in serum decreased (P < 0.001). Decrease (P < 0.001) was recorded in serum FSH and testosterone after 2 and 4 weeks of zinc deficiency. The changes were more prominent after 4 weeks of synthetic zinc deficient diet. The results indicate that zinc deficiency during prepubertal period affects the prostate structure, total protein concentration, enhanced protein carbonyl concentration, nitric oxide as well as acid phosphatase activities and impaired hydroxysteroid dehydrogenase activities. Evidently these changes could be attributed to dysfunction of dorso-lateral and ventral prostate after dietary zinc deficiency as well as impairment of metabolic and secretory activity, reduced gonadotropin levels by hypothalamus -hypophysial system which is indicative of a critical role of zinc in maintaining the prostate integrity.

Catalase in testes and epididymidis of wistar rats fed zinc deficient diet.

Catalase activities have been evaluated in testes and caput and cauda epididymis of Wistar rats fed on zinc deficient diet for 2 and 4 weeks. The enzyme activity has been measured as chromic acetate formed by heating of dichromate (in acetic acid) in presence of H(2) O(2) with perchromic acid as an unstable intermediate. Observed non-significant increase in catalase activity in testes as well as in caput and cauda epididymis of 2 weeks experiments has been related to low levels of H(2) O(2) produced in two organs whereas significant (P<0.01/0.001) increase in catalase activity in 4-weeks experiments indicate for increased oxidative stress due to phagocytotic activity of Sertoli cells in testes and damaged spermatozoa in epididymis. Thus, zinc deficiency increases catalase activity in testes and epididymis.

Testicular protein profile (SDS-PAGE) study of zinc deficient Wistar albino rat.

Present study has revealed that zinc plays important role in regulating the production and secretion of proteins at transcriptional or translational level. Study has firmly depicted the change in the levels of polypeptide of 70 kDa in zinc deficient group. The protein pattern in pair fed group has been affected mainly to combat the insult due to low food intake.

Effect on histological and sperm kinetics in DBP exposed Wistar rats.

Di-n-butyl phthalate (DBP) is a ubiquitous environmental pollutant, extensively used as a softener for polyvinyl chloride resins. A study was conducted to evaluate its effect on reproductive function of Wistar rats. DBP was given orally at a dose of 500, 1000 and 1500 mg kg(-1) body weight for 7 days. Evaluating histological and fertility parameters assessed reproductive function. Significant reduction in seminiferous tubule diameter, Leydig cell nuclear diameter (except at dose 500 mg), number of primary spermatocytes, secondary spermatocytes and spermatids were observed. Caudal sperm density and viability reduced significantly. Decrease in serum testosterone was also observed. Evidence indicates that DBP exposure causes dose dependent testicular toxicity and has the potential to induce adverse effect.

Cloning and characterization of GTP-binding proteins of Mycobacterium tuberculosis H(37)Rv.

GTP-binding proteins (G-proteins) are highly conserved signaling molecules that participate in cellular signaling and bacterial pathogenesis by regulating the activity of cognate GTPases. However, the exact role of G-proteins in the pathogenesis of Mycobacterium tuberculosis is poorly understood. The complete genome sequence of M. tuberculosis H(37)Rv, suggests the presence of several homologs of bacterial G-proteins. In the present study, three G-proteins, Era, Obg and LepA of M. tuberculosis H(37)Rv were cloned and expressed in Escherichia coli. Purified proteins showed GTP-binding and hydrolyzing activities. A point mutation in the conserved GTP-binding motif, AspXXGly (Asp to Ala) in Era (Asp-258) and Obg (Asp-212) proteins resulted in the loss of the associated activities, confirming that known key residues in well-established G-proteins are also conserved in mycobacterial homologs. This study confirms that Era, Obg and LepA of M. tuberculosis H(37)Rv possess GTPase activity and provide a platform to understand the physiological significance of these proteins in associated pathogenesis.

Short-term zinc deficiency in diet induces increased oxidative stress in testes and epididymis of rats.

In order to determine the effects of Zinc deficient diet on oxidative stress in testis and epididymis, various parameters viz: total proteins, lipid peroxidation, hydroperoxides, antioxidant capacity and enzymatic activities are evaluated in rats fed on zinc deficient diet for 2, 4 and 6 weeks. Total proteins, water and lipid solouble antioxidant capacity decreased while lipid peroxidation (TBARS) and hydroperoxides concentration increased in testes, caput and cauda epididymis except in 2ZD (testes) where hydroperoxides revealed a significant decrease. GSH decreased in testes and caput and cauda epididymis. GPx and gamma-GT activities increased in testes and caput and cauda epididymis of zinc deficient rats. Further, GST increased in testes but exhibited decreases after 2 and 4 weeks and an increase after 6 weeks in caput and cauda epididymis of zinc deficient rats. GR activities decreased in testes but it increased in caput and cauda epididymis of zinc deficient rats. Thus, zinc deprivation results in increased sensitivity to oxidative stress. All these may have been as a consequence of increased ROS generation and/or decreased zinc dependent antioxidant processes.

Metallothionein in male reproductive organs of adrenalectomized and hydrocortisone-treated Wistar rats.

Adrenalectomy resulted in an increase in metallothionein (MT) levels in testes, caput and cauda epididymis and prostate of rats but not in seminal vesicles where its levels decreased significantly. Inspite of administration of hydrocortisone, MT in testes, prostate (1.2 mg), caput (0.3 mg days 2, 8; 0.6 mg and 1.2 mg) and seminal vesicles (0.3 mg day 2, 4; 0.6 mg and 1.2 mg) remained increased. Thus adrenal insufficiency/hydrocortisone has no direct influence on MT levels. However, the increased levels of MT can be related to its ability to protect the cells from free radical damage caused by atrophy of reproductive tissues in adrenalectomised rats. Exogenously administered hydrocortisone to ADX rats resulted in return to ADX state as hydrocortisone metabolizes (half-life < 12 hr) and hence MT levels remained increased. The observations could provide a clue for the physiological functioning of the male reproductive tissue in a state of adrenal deprivation and hormonal supplementation.

Nucleoside diphosphate kinase-like activity in adenylate kinase of Mycobacterium tuberculosis.

Ak (adenylate kinase) is a ubiquitous enzyme that catalyses a reversible high-energy phosphoryl-transfer reaction between ATP and AMP to form ADP. In the present study, the Ak gene (adk) of Mycobacterium tuberculosis was cloned, expressed in Escherichia coli and purified as a glutathione S-transferase fusion protein. Purified Ak converted AMP into ADP in the presence of [gamma-32P]ATP or [gamma-32P]GTP. Replacement of arginine-88 of adk with glycine resulted in the loss of enzymic activity. The purified protein also showed Ndk (nucleoside diphosphate kinase)-like activity as it transferred terminal phosphate from [gamma-32P]ATP to all nucleoside diphosphates, converting them into corresponding triphosphates. However, Ndk-like activity of Ak was not observed with [gamma-32P]GTP. Immunoblot analysis of various cellular fractions of M. tuberculosis H37Rv revealed that Ak is a cytoplasmic protein. The dual activity of Ak as both nucleoside mono- and di-phosphate kinases suggested that this enzyme may have a role in RNA and DNA biosynthesis in addition to its role in intracellular nucleotide metabolism.

Effect of dietary zinc deficiency on metallothionein concentration of epididymal luminal fluids of weanling Wistar albino rats.

Metallothionein (NIT) and zinc concentrations have been estimated in luminal fluids of caput/corpus and cauda epididymis and serum of zinc deficient (ZD), pairfed (PF) and control--ad libitum fed (ZC) groups of Wistar rats. MT decreased significantly in luminal fluids of caput corpus and cauda epididymis and serum of zinc deficient rats as compared to their respective controls. However, the decrease was non-significant in luminal fluids of corpus epididymis and serum of 4-weeks zinc deficient animals as compared to their control. Zinc levels also declined significantly in luminal fluids of epididymis and serum of zinc deficient rats as compared to their respective pairfed and control groups. Thus zinc deficiency state reduces zinc and MT concentrations in luminal fluid of epididymis and serum.

Comparative study of three different mycobacterial antigens with a novel lipopolysaccharide antigen for the serodiagnosis of tuberculosis.

Demonstration of Mycobacterium tuberculosis in a smear or culture is the most reliable method for diagnosing tuberculosis (TB). In the last 10 years, several enzyme-linked immunosorbent assays (ELISAs) based on mycobacterial antigens (such as antigen 60, 38 kDa antigen, and antigen Kp90) have been used for the rapid diagnosis of TB. In this study, we report the isolation of an immunodominant lipopolysaccharide (LPS) antigen from M. tuberculosis H(37)Rv, which can be used for the serodiagnosis of TB. The LPS antigen was compared with three commercially available mycobacterium-specific antigens for the detection of TB. The antigens were evaluated using serum samples obtained from 59 Indian patients (19 patients with active pulmonary TB, 20 with extrapulmonary TB, and 20 with nontuberculous pulmonary disease) and 20 healthy adults. Antigen 60 IgG (sensitivity 89%, specificity 97%) and LPS (sensitivity 84%, specificity 97%) were more sensitive and specific than 38 kDa antigen IgG (sensitivity 79%, specificity 97%) and Kp90 IgA (sensitivity 82%, specificity 40%). These results indicate that the LPS antigen can be used as a sensitive tool for the serodiagnosis of TB and could be utilized to develop an ELISA for the screening of patients for TB.

Effect of adrenalectomy on rat epididymidis.

AIM: To investigate the effect of adrenalectomy (ADX) on the epididymidis of Sprague-Dawley rats. METHODS: The histological, biochemical (cholesterol protein, zinc, copper, alkaline and acid phosphatase aryl sulphatase, lactic dehydrogenase and leucine amino peptidase) and hormonal (FSH, LH and testosterone) changes of caput and cauda epididymis in ADX rats were observed. RESULTS: Organ wet weight, histological studies and morphometric measurements indicated a cellular degeneration in caput and cauda epididymis of ADX rats. Serum testosterone level was significantly lower in ADX than in sham-operated rats, while the serum FSH and LH were below the detection limit of 1 mIU/mL. The enzymatic activity was higher in ADX than in sham-operated rats. Epididymal zinc level increased whereas copper level decreased in ADX rats compared to the sham-operated. CONCLUSION: Adrenalectomy leads to degeneration of caput and cauda epididymidis epithelial cells as a result of decreased supply of testosterone.

Effect of adrenalectomy and hydrocortisone on ventral prostate of rats.

AIM: To study the effects of adrenalectomy and hydrocortisone on the ventral prostate of SD rats. METHODS: In adrenalectomised (ADX) and ADX + hydrocortisone (1, 2, or 4 mg) treated rats, the prostatic histology and the cholesterol, protein, zinc, and copper levels and the enzymic profile (acid phosphatase, alkaline phosphatase, aryl sulphatase, lactic dehydrogenase, and leucine aminopeptidase) in the prostatic tissue were determined; the serum hormonal profile (testosterone, FSH and LH) was also assayed. RESULTS: Adrenalectomy caused a progressive degeneration in prostatic structure that was not reversed by hydrocortisone treatment. The serum testosterone were significantly lower in ADX than in sham operated rats and lower in ADX + hydrocortisone than in ADX-C rats (P < 0. 01). The serum FSH and LH were below the detection limit of 1 mIU/mL. The enzymatic activity was higher in ADX than in sham operated rats and higher in ADX + hydrocortisone than in ADX-C rats (P < 0.05-0.01). The prostatic zinc levels were significantly higher in sham operated than in ADX, and higher in ADX-C than in ADX + hydrocortisone rats (P < 0.05-0.01). The prostatic copper level was significantly lower in sham operated than in ADX, and lower in ADX-C than in the ADX + hydrocortisone rats (P < 0.01). CONCLUSION: In rats, adrenalectomy leads to pathological and functional changes of the prostate. Hydrocortisone treatment at the doses employed did not reverse these changes.

SDS-PAGE analysis of caput epididymis proteins in rats receiving a zinc deficient diet.

Caput epididymis proteins from control, pairfed and zinc deficient (ZD) wistar weanling albino rats after 2-, 4-, 6- and 8-weeks were examined using SDS-PAGE followed by densitometric scanning of the gels. In comparison to the control and pairfed rats, ZD rats displayed new proteins. These included a Mr 42 kDa from 2ZD, Mr 47.5, 27.5, 23.2 and 16.0 kDa from 4ZD and Mr 87 and 14.2 kDa from 6ZD group. The 8ZD group, however, revealed no additional protein bands over controls. Further, several other proteins were missing from ZD rats. These included Mr 93 and 71 kDa from 2ZD; 93, 90, 79, 67, 62, 55 and 15.3 kDa from 4ZD; 60, 45.5, 34, 30 and 24 kDa from 6ZD and 41.5, 33 and 27.5 kDa bands from 8ZD group. The results indicate that the induced Zn-deficient state may be responsible for the altered protein patterns in the caput epididymis. The duration of low Zn uptake period also appears to influence the protein pattern in caput epididymis.

Zinc, copper and hydrolytic enzymes in epididymis of hydrocortisone treated rat.

Administration of glucocorticoid (1, 2 and 4 mg) in excess leads to degeneration of epididymides as supported by cellular degeneration, sperm density and morphometric measurements. Zinc level increased statistically after 1, 2 and 4 mg hydrocortisone treatment while copper increased after 1 and 2 mg treatment. Cholesterol, protein and leucine aminopeptidase levels increased and decreased significantly in caput and cauda respectively. Activity of alkaline phosphatase reduced significantly while the treatment of hydrocortisone at different doses elevated acid phosphatase, aryl sulphatase and lactate dehydrogenase activities. Evidently, these changes are as a result of onset of cellular degeneration leading to impairment of metabolic/secretory activity of epididymal cells. The possible involvement of pituitary-testis axis in hydrocortisone induced epididymal degeneration and functional inhibition has been discussed.

Effect of adrenalectomy and adrenalectomy+hydrocortisone treatment on histopathological, biochemical and zinc and copper profiles in rat testes.

Degenerative changes such as decreased seminiferous tubule diameter, Leydig cell nuclear diameter, spermatogenic arrest, oedematous fluid in the interstitium and lumen of seminiferous tubules and increased levels of zinc, copper and enzymes (lactate dehydrogenase, LDH; leucine aminopeptidase, LAP; and aryl sulphatase) in adrenalectomised rats suggest a possible role of adrenal cortex and its hormones in spermatogonial cell proliferation and subsequent differentiation, homeostasis of biological trace elements and behaviour of enzymes. Atrophy of Leydig cells and the degenerative changes in testes of adrenalectomised rats can be attributed to reduced supply of testosterone. Hydrocortisone, administered through a single dose acted as hyperstate of hydrocortisone for a short duration, thereby inhibiting steroidogenesis either directly by affecting Leydig cell testosterone production or indirectly by affecting the release of LH from pituitary gland and thus caused degeneration of germinal epithelium. Once hydrocortisone (half life < 12 hr) was metabolized, the animals returned to adrenalectomised state, the degeneration persisted. Thus, hydrocortisone administered through a single dose was insufficient to sustain spermatogenesis. Chronic administration at physiological dose may renew spermatogenesis. Increased levels of LDH, LAP and arylsulphatase are, probably, necessary for cellular degeneration. Zinc and copper exhibited an increase and the rise can be corroborated to (1) failure of regulatory mechanism(s) that control the flow of the elements across the blood-testes barrier; and (2) increased oedematous fluid formed by cellular deaths of the germinal epithelium.

Light and electron microscopic changes in the ovary of zinc deficient BALB/c mice.

Female BALB/c strain of mice fed on Zn deficient diet for 2-, 4- and 6- weeks exhibited prolonged diestrous phase with only VII types of follicles instead of VIII as compared to their respective control and pairfed. Light microscopic studies displayed increased atresia, cessation of oogenesis and ovulation, degeneration of follicular cells of zona granulosa, clumped chromatin of oocyte and disrupted zona pellucida and corona radiata. Ultrastructural studies of peripheral follicular and theca interstitial cells of type VI and VII follicles revealed swollen mitochondria, dilated ERs (free of RNP particles), increased lysosomes, several necrotic areas of cytoplasm and pyknotic nuclei. Conclusively, Zn deficiency may lead to (1) reduction in energy, protein intake and in secretion of GnRH by hypothalamus and LH and FSH by hypophysis, (2) increased synthesis and/or secretion of prolactin. (3) reduced output of estrogen, and (4) eventually slow growth or arrest of ovulation or atresia of the growing follicles in the ovary.

Zinc, copper and selenium in reproduction.

Of the nine biological trace elements, zinc, copper and selenium are important in reproduction in males and females. Zinc content is high in the adult testis, and the prostate has a higher concentration of zinc than any other organ of the body. Zinc deficiency first impairs angiotensin converting enzyme (ACE) activity, and this in turn leads to depletion of testosterone and inhibition of spermatogenesis. Defects in spermatozoa are frequently observed in the zinc-deficient rat. Zinc is thought to help to extend the functional life span of the ejaculated spermatozoa. Zinc deficiency in the female can lead to such problems as impaired synthesis/secretion of (FSH) and (LH), abnormal ovarian development, disruption of the estrous cycle, frequent abortion, a prolonged gestation period, teratogenicity, stillbirths, difficulty in parturition, pre-eclampsia, toxemia and low birth weights of infants. The level of testosterone in the male has been suggested to play a role in the severity of copper deficiency. Copper-deficient female rats are protected against mortality due to copper deficiency, and the protection has been suggested to be provided by estrogens, since estrogens alter the subcellular distribution of copper in the liver and increase plasma copper levels by inducing ceruloplasmin synthesis. The selenium content of male gonads increases during pubertal maturation. Selenium is localized in the mitochondrial capsule protein (MCP) of the midpiece. Maximal incorporation in MCP occurs at steps 7 and 12 of spermatogenesis and uptake decreases by step 15. Selenium deficiency in females results in infertility, abortions and retention of the placenta. The newborns from a selenium-deficient mother suffer from muscular weakness, but the concentration of selenium during pregnancy does not have any effect on the weight of the baby or length of pregnancy. The selenium requirements of a pregnant and lactating mother are increased as a result of selenium transport to the fetus via the placenta and to the infant via breast milk.

Histological and biochemical changes in testis of zinc deficient BALB/c strain of mice.

Zinc, protein, cholesterol, phospholipids, alkaline phosphatase (AlPase), acid phosphatase (AcPase), adenosine-5-triphosphatase(ATPase) and histology were studied in testis of zinc-deficient mice. Zinc and protein decreased in the 3-week experiment whereas they increased in the 6-week experiment. Zinc is involved in several functions of the cell and is regulated by hormones. Inhibition of spermatogenesis indicates for decreased zinc levels in 3-week whereas the increase in 6-week experiment indicates for accumulation of zinc in oedomatous fluid and uncontrolled diffusion of zinc across the blood testis barrier. Glycogen decreased in the 3-week as well as 6-week experiments due to blockage of androgen and spermatogenesis. Cholesterol and phospholipids increased in the 3-week experiment and decreased in 6-week experiment as both the parameters are related to steroidogenesis. Zinc deficiency leads to aspermatogenic condition and comparatively less injury to non-germinal cells. This could have blocked the transport of material across the testis barrier and therefore might have increased AlPase levels. Increased AcPase, probably represents lysosomal enzymes, as the cell debris of disorganised epithelium are to be digested and removed. ATPase increased in 3-week experiment and can be correlated to increased demands of energy of testicular cells to overcome the insults of zinc deficiency whereas the decrease in 6-week experiment could be as a result of inhibition of spermatogenesis.

Selenium--its biological perspectives.

Selenium is an essential trace element at lower concentrations and toxic at higher concentration. Animals can metabolize both inorganic and organic forms and convert non methylated Se to mono--or di--or tri--methylated forms, of which, mono-methylated forms are most toxic. Glutathione reductase converts selenoglutathione to H2S in liver and erythrocytes and is ultimately excreted. Se effects the toxicities of xenobiotic agents, provides antagonistic effect to Sulphur and co-administration with Zn increase Se retention in certain organs. At its toxic level (4-8 ppm) it increases Cu contents of heart, liver and kidney and has detoxifying or protecting effect against Cd and Hg. It is a prosthetic group of several seleno metalloenzymes. The concentration of the element is decreased in serum/plasma or erythrocytes of patients of AIDS, trisomy-21, Crohn's and Down's syndrome, phenylketonurea, Keshan's disease and cancer. Rather, the element has antiproliferative and cancer protecting effect. Se content of testes increases considerably during pubertal maturation and, during Se deficiency, the supply to the testes has priority over the other tissues. The element is localized in the mitochondrial capsule protein (MCP) and is involved in biosynthesis of testosterone. Neither the age of mother nor the concentration of Se during pregnancy has any effect on weight of baby or the length of pregnancy. Se levels in human milk is affected by maternal intake and its requirements by infants and young children are higher for their rapid growth. Clinical symptoms of its toxicity include severe irritations of respiratory system, metallic taste in mouth, formication of nose, signs of rhinitis, lung edema and brancho-pneumonia. The typical garlic odour of breath and sweat is due to dimethyl-selenide.