Tumor necrosis factor alpha system in the bovine oviduct: a possible mechanism for embryo transport

Active contractile pattern of the oviduct occurs during the periovulatory period for the movement of the gamete/embryo, which is strictly regulated by endocrine and paracrine/autocrine factors. In this review, an involvement of tumor necrosis factor alpha (TNFalpha) in the regulation of cow oviductal contraction is discussed. Oviductal epithelial cells express TNFalpha ligand and it's both receptor types; high expression during the follicular and postovulatory stages, while low expression during luteal stage and thus, TNFalpha system in the cow oviduct is most active during the periovulatory period. The immune cells present in large numbers in the oviduct during the periovulatory period of the estrus cycle, and these cells are also considered as another potential source for the TNFalpha in the oviduct. Using in vitro models, TNFalpha clearly stimulated local production and release of contraction related substances such as prostaglandins (PGs), endothelin-1 (ET-1) and angiotensin II (Ang II). Since these substances have been shown to activate directly the oviductal contraction in vitro, TNFalpha appears to stimulate the oviductal contraction during the periovulatory period and contribute to create an optimal local environment suitable for gamete/embryo transport. In addition, the ability of embryo to act as a source of TNFalpha in the oviduct cannot be excluded. To support this idea, the embryo at 2-4 cells stages indeed express TNFalpha, so that the minute quantities of TNFalpha secreted by the embryo may further acts locally to enhance the production of PG, ET-1 and Ang II in the oviduct, which may result in an active oviductal contraction in the microenvironment around the embryo. This may ensure the embryo to migrate into the uterus at the optimal time.     

Expression and regulation of Enpp2 in rat uterus during the estrous cycle

Ectonucleotide pyrophosphatase/phosphodiestrase 2 (Enpp2) isolated from the supernatant of human melanoma cells is a lysophospholipase D that transforms lysophosphatidylcholine into lysophospatidic acid. Although multiple analyses have investigated the function of Enpp2 in the hypothalamus, its role in the uterus during the estrous cycle is not well understood. In the present study, rat uterine Enpp2 was analyzed by RT-PCR, Western blotting, and immunohistochemistry. Quantitative PCR analysis demonstrated that uterine Enpp2 mRNA was decreased during estrus compared to proestrus and diestrus. To determine whether uterine Enpp2 expression is affected by sex steroid hormones, immature rats were treated with 17β-estradiol (E2), progesterone, or both on postnatal days 14 to 16. Interestingly, the expression of Enpp2 mRNA and protein were down-regulated by E2 in the uterus during estrus but not during proestrus or diestrus, suggesting that Enpp2 may play a role in uterine function during estrus. Enpp2 is primarily localized in the stromal cells of the endometrium during proestrus and estrus. During diestrus, Enpp2 was highly expressed in the epithelial cells of the endometrium. Taken together, these results suggest that uterine Enpp2 may be regulated by E2 and plays a role in reproductive functions during female rat development.     

Expression patterns of the implantation-associated genes in the uterus during the estrous cycle in mice

The mRNA expression patterns of EGF, HB-EGF, Amphiregulin, EGF receptor, IGF-1, CSF-1, IL-1 alpha, IL-1 beta, IL-1 receptor type 1, IL-1 receptor antagonist, LIF, COX-1, COX-2, Mucin-1, calcitonin, and rat USAG-1 mouse homologue, all of which are involved in the process of conceptus implantation to the endometrium, were examined during the estrous cycle by means of real-time quantitative PCR. COX-2, HB-EGF, LIF, Mucin-1, CSF-1, IL-1 alpha, IL-1 beta, and IL-1 receptor antagonist were temporally regulated during the estrous cycle and highly expressed during the estrous stage. In the case of COX-1, EGF, IGF-1, and EGF receptor, the highest mRNA expression was during the diestrous stage. In contrast, the rat USAG-1 mouse homologue mRNA expression did not change during the estrous cycle. These results indicate that rat USAG-1 mouse homologue expression at implantation might be specifically regulated by embryonic factors rather than the maternal environment.     

Changes of receptor mRNAs for oxytocin and estrogen during the estrous cycle in rat uterus

Oxytocin receptor (OTR) mRNA levels increase dramatically near term and is potently stimulated by estrogen because increased OTR mRNA levels result from estrogen treatment in ovariectomized rat uterus. In this study, OTR, estrogen receptor (ER) alpha and ERbeta mRNA levels in the rat uterus during the estrous cycle were examined by quantitative RT-PCR. OTR mRNA levels during the estrous cycle began to increase on diestrus (P<0.05, vs value on estrus), reached maximal increase both in the morning (1000-1130 hr) and afternoon (1600-1630 hr) on proestrus (P<0.01, vs metestrus, diestrus and estrus) and then declined on estrus. In contrast ER alpha mRNA levels began to decrease on diestrus, reached statistical significance both in the morning and the afternoon on proestrus (P<0.01, vs metestrus, diestrus and estrus) and returned to the value of metestrus on estrus. ERbeta mRNA levels were low in the morning and the afternoon on proestrus (P<0.01, vs metestrus and estrus) and also returned to metestrus values on estrus. Treatments with estrogen for 3 days significantly decreased both ERalpha and ERbeta mRNA levels. It can be concluded from these results that during the estrous cycle, OTR mRNA levels in rat uterus predominantly increase at proestrus with a decrease in ERalpha and ERbeta mRNA levels, which is probably due to the increased estrogen levels in circulation before ovulation.     

Progesterone receptor mRNA levels during pregnancy, labor, lactation and the estrous cycle in rat uterus

Progesterone plays important roles in the regulation of female reproduction. In this study, progesterone receptor (PR) mRNA levels in rat uterus during pregnancy, labor, lactation and the estrous cycle were examined by competitive RT-PCR. During pregnancy and lactation, PR mRNA levels had decreased on day 20 of pregnancy (P20) and P21 compared with P15 but increased during labor. After a decline on day 1 of lactation (L1), PR mRNA levels had increased again on L3 and L14 compared with P15, P18, P20, P21 and P21pm (at 2200-2300 h on P21). There was no significant change in the PR mRNA level during the estrous cycle. The PR mRNA level did not change during 1 week of progesterone treatment or afterwards. Injection of 17beta-estradiol did not affect PR mRNA levels in rats treated with progesterone or those without any injections. In rats on P18, 17beta-estradiol injection did not change PR mRNA levels after sham-operation but induced an increase in PR mRNA levels of rats ovariectomized 6 h before the treatment. These results suggest that uterine PR mRNA levels are differently regulated during late pregnancy, labor and lactation, and during labor estrogen is one of the essential factors for the increase in PR mRNA levels.     

Tumor necrosis factor as a potential mediator of acute metabolic and hormonal responses to endotoxemia in calves

The effects of coliform endotoxin (E) and recombinant bovine tumor necrosis factor alpha (TNF) were compared with respect to clinical signs of disease and changes in plasma metabolite and pituitary and pancreatic hormone concentrations in calves. In addition, changes in plasma TNF concentration during each challenge exposure were quantitated by use of radioimmunoassay. Healthy Holstein bull calves with mean body weight of 90 kg were each given, in order, on different days, saline solution (5.0 ml, IV, day 1, n = 4), E (type 055:B5, 1.0 micrograms/kg of body weight IV, day 2, n = 4) and TNF (5.0 micrograms/kg IV, day 9, n = 3). Jugular venous blood samples, rectal temperature reading, and PCV were obtained at hourly intervals before (2 hours) and after challenge exposure. The PCV increased (P less than 0.05) after E and TNF administrations for the first 5 hours, then returned to normal in calves given E, but decreased and remained low in calves given TNF through 24 hours. Plasma triglyceride and nonesterified free fatty acids concentrations were increased through 10 hours (P less than 0.05) after E administration, whereas triglyceride and nonesterified free fatty acids concentrations were not significantly affected by TNF administration. Increase in blood glucose concentration at 1 hour after administration of E and TNF was followed by prolonged hypoglycemia that lasted through 6 hours. Changes in plasma insulin concentration paralleled the observed changes in glucose concentration, initially increased at 2 hours after E and TNF (P less than 0.05) administrations, but then tended to decrease below control values thereafter.(ABSTRACT TRUNCATED AT 250 WORDS)     

Bartonella spp infection as a possible cause of uveitis in a cat

A 6-year-old castrated mixed-breed cat was evaluated because of unilateral anterior uveitis. The cat was seronegative for antibodies to Toxoplasma gondii, coronaviruses, and feline immunodeficiency virus, and antigens for FeLV p27 and Cryptococcus neoformans. Antibodies to Bartonella spp were detected in serum and aqueous humor. The antibody coefficient (C value) for IgG antibodies to Bartonella spp in the aqueous humor was 4.42; values > 1 suggest ocular production of antibodies and supports a diagnosis of ocular infection. Topical administration of prednisolone and oral administration of prednisone failed to induce a response; however, the uveitis resolved rapidly after the cat was given doxycycline orally. Clinical or laboratory evidence of immunodeficiency in this cat was not detected. Detection of a serum IgG antibody titer to Bartonella spp and ocular production of IgG antibodies to Bartonella spp, exclusion of other causes of uveitis, and response to doxycycline suggests that the cat may have had bartonellosis resulting in uveal tract inflammation.     

Tumor necrosis factor activity in the circulation of horses given endotoxin

Serum and plasma from horses injected with endotoxin was examined for cytotoxic activity. Each of the cell lines, L929 and WEHI 164 clone 13, was sensitive to the cytotoxic effects of equine serum; however, a precipitation artifact caused by the use of isopropanol in the WEHI assay limited the use of this assay to samples containing less than 2 mg of protein/ml. In foals treated with a sublethal IV bolus of 5 micrograms of lipopolysaccharide (LPS)/kg and in adult horses given a low-dose continuous infusion of LPS (30 ng/kg/h for 4 hours), cytotoxic activity was detected in all serum or plasma samples taken between 30 minutes and 4 hours after LPS infusion began. In horses given either continuous or bolus LPS infusions, circulating cytotoxic activity peaked at 1 to 2 hours before decreasing sharply. The onset of pyrexia after LPS infusion coincided with the appearance of circulating cytotoxic activity, but the temperature remained high, even after cytotoxic activity disappeared. Treatment of horses with flunixin meglumine (1 mg/kg) appeared to blunt the pyrexic effect of low-dose continuous LPS infusion, but had no significant effect on circulating cytotoxic activity. Incubation of serum samples with an antibody raised against a portion of human tumor necrosis factor (TNF) resulted in the removal of greater than 90% of serum cytotoxicity, suggesting strongly that the cytotoxic activity was attributable to TNF. These findings are consistent with the hypothesis that TNF is an early acting mediator of the effects of endotoxin in the horse.     

Tumor necrosis factor-alpha and nitrite/nitrate responses during acute mastitis induced by Escherichia coli infection and endotoxin in dairy cows

Concentrations of tumor necrosis factor-alpha (TNF-alpha) and of NO(x) (sum of nitrite and nitrate as indicators of endogenous nitric oxide production) in milk and blood plasma were measured in three mastitis models in dairy cows in early lactation. Escherichia coli P4:O37 bacteria or endotoxin O111:B4 were administered into both left quarters of 12 and 6 cows, respectively. Six of the E. coli-infected cows were treated with a bactericidal antibiotic (Enrofloxacin; Bayer AG, Leverkusen, Germany) i.v. at 10 hr and subcutaneously (sc) at 30 hr after infection. NO(x) concentrations transiently increased maximally 10- to 11-fold in milk of E. coli-infected quarters with or without antibiotic treatment at 24 hr and after endotoxin administration. NO(x) concentrations did not change in milk of unchallenged quarters and in blood plasma. Increases of NO(x) were proceeded by a transient (96- to 149-fold) rise of milk TNF-alpha concentrations, which in endotoxin-administered quarters was maximal at 6 hr and in infected quarters without or with Enrofloxacin treatment at 10 and 14 hr. In blood plasma TNF-alpha concentrations only moderately increased to peaks in endotoxin-administered cows at 6 hr and in E. coli-infected cows at 14 hr postchallenge. In one severely sick, nontreated E. coli-infected cow milk, TNF-alpha response at 14 hr was excessive and followed by a spectacular rise of NO(x) concentration in milk between 48 and 72 hr. In conclusion, a possible clinical relevance of nitric oxide production associated with a rise of intramammary and systemic TNF-alpha during acute mastitis by E. coli infection and endotoxin in lactating dairy cows is indicated, but could not be inhibited by antibiotic treatment.     

Tumor necrosis factor alpha inhibits in vitro bovine embryo development through a prostaglandin mediated mechanism

Mastitis or other infectious diseases have been related to reduced fertility in cattle. Inflammatory cytokines such as tumor necrosis factor a (TNFa) are released in response to infection and may have negative effects on embryo development. In the current study the effect of exposure to TNFa on the development of in vitro fertilized bovine embryos was examined. Indomethacin, a prostaglandin synthesis inhibitor, was used to determine if blockade of prostaglandin synthesis would alter the effects of TNFa. Ovaries were obtained from a local abattoir and immature COC were isolated from 2-10 mm follicles, in vitro matured and fertilized. After fertilization, groups of presumptive zygotes were randomly placed into either control development medium, medium containing 25 ng/mL TNFa or medium containing 25 ng/mL TNFa plus 1 μg/mL indomethacin. The proportion of blastocysts formed was assessed at day 7 of culture. Fewer embryos exposed to TNFa alone reached the blastocyst stage (17.5 ± 2.4%, P < 0.01) compared with controls (30.5 ± 2.4%) or embryos developed in TNFa plus indomethacin (25.8 ± 2.8%). There was no difference between control embryos and embryos developed in TNFa plus indomethacin. These results indicate that TNFa is inhibitory to the in vitro development of bovine embryos and that this inhibition may be mediated by prostaglandins because it can be blocked by indomethacin.     

Epidermal growth factor and epidermal growth factor receptor immunoreactivity in the endothelial cells of the uterine artery and its branches during different stages of the estrous cycle in the pig

The uterine artery and its branches are the most important vessels that supply the uterus with blood, nutrients and active substances. Epidermal growth factor (EGF) and its receptor (EGFR) are expressed in many tissues, including reproductive organs, and is involved in angiogenesis, embryo implantation and development as well as in proliferation and differentiation of various cells. The aim of our study was to determine EGF and EGFR immunoexpression in the uterine artery and its branches during the estrous cycle in the pig. The experiment was performed on cryostat sections of the uterine artery and its branches stained immunohistochemically by ABC method. Light microscopic observations revealed the phase-related immunoreactivity of EGF and EGFR in the endothelial cells of the uterine artery and its branches. The highest intensity of EGF and EGFR immunoreaction in endothelial cells of the uterine artery was observed in the follicular phase. A significant decrease in the intensity of EGF and EGFR immunoreactivity was found in the middle luteal phase. Similar results of the immunostaining were found with regard to EGFR. In the endothelium of the uterine arterial branches, a significant increase in the intensity of EGF and EGFR-immunoreactivity was observed in the middle luteal phase. A decrease in the intensity of EGF immunostaining was observed in the late luteal phase. The phase-related expression of EGF and EGFR in the endothelium of the uterine artery and its branches suggest the modulatory effect of EGF and its receptor on the uterine artery and the region supplying these vessels.     

Corneal necrosis and sequestration in the cat: a review and record of 100 cases

A distinct type of ulcerative keratitis, apparently specific to the cat, and of unknown aetiology, has been noted by many authors. This condition is described and a review of the literature is provided. Clinical signs presented are analysed, together with breed, sex and age incidence, and a record of 100 cases noted over a 12 year period is provided. Earlier observations of possible causation are discussed and a note made of further investigations needed to establish the aetiology of this corneal disorder.     

Development of a model for inducing transient insulin resistance in the mare: preliminary implications regarding the estrous cycle

Peripheral insulin resistance is the failure of proper cellular glucose uptake in response to insulin. Insulin resistance and hyperinsulinemia are associated with several disease states in the horse and reproductive function disturbances in humans, including polycystic ovarian syndrome. To test the hypothesis that insulin resistance (IR) and hyperinsulinemia disrupt the estrous cycle in mares, two experiments were conducted to first develop a model to induce IR and to then examine the effect of this model on the duration of the estrous cycle. In Exp. 1, a hyperinsulinemic-euglycemic clamp (HEC) procedure was performed on seven mares to determine insulin sensitivity before and immediately following infusion of a heparinized lipid solution. The HEC procedure was repeated 1 wk after lipid infusion. Mares developed IR following the lipid infusion (P < 0.05), and some individuals maintained IR for up to 1 wk. Mares also exhibited increased blood insulin both immediately following treatment and 1 wk later (P < 0.05). In Exp. 2, induction of insulin resistance by lipid solution was not accompanied by changes in circulating concentrations of luteinizing hormone, and duration of the luteal phase, compared with the duration of untreated luteal phases. Nonetheless, lipid infusion and the resultant insulin resistance were associated with an increased interovulatory period (P < 0.05), and peak concentrations of progesterone (P < 0.05) were higher during the treated vs. untreated luteal phases of the estrous cycle. The results from the preliminary study suggest that infusion of a lipid solution may induce transient insulin resistance and hyperinsulinemia. The resulting insulin resistance and hyperinsulinemia may modify characteristics of the estrous cycle, perhaps at the level of the ovary.     

Concurrent infection with Cryptococcus neoformans/gattii species complex and Mycobacterium avium affecting the subcutis and bone of a pelvic limb in a cat

This paper describes a cat with severe localised infections with Cryptococcus neoformans/gattii species complex and Mycobacterium avium affecting the subcutis and underlying fascia and bone of the right pelvic limb. The simultaneous isolation of both pathogens in this patient was unexpected and posed unique issues concerning both diagnosis and clinical management. The aetiopathogenesis of this infection is discussed in relation to aspects of diagnosis and therapy.     

Pharmacokinetic/pharmacodynamic modelling of roxithromycin for the inhibitory effect of tumour necrosis factor-alpha and interleukin-6 production in dogs

The objective of the present study was to determine and characterize the relationship between the plasma concentration of roxithromycin, and its inhibitory effect on cytokine production, in order to predict its possible clinical relevance. Six healthy beagle dogs received a single intravenous dose of 20-mg roxithromycin per kg body weight. Blood samples were obtained at different time points. The plasma was analysed with respect to roxithromycin, tumour necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6). The concentration-effect relationship was explored by modelling the data using two compartmental model and an indirect response model with an E(max) concentration-effect relationship. The estimated pharmacokinetic parameters (geometric mean) were as follows: V(c) = 2.59 l; k(10) = 0.08/h; k(12) = 0.26/h; k(21) = 0.40/h. The pharmacodynamic parameters (geometric mean) for the inhibitory effect on cytokine production induced by heat-killed Staphylococcus aureus (HKSA) were for TNF-alpha (k(in) = 1.42 microg/h; k(out) = 1.10 microg/h; EC(50) > 5.69 mg/l) and for IL-6 (k(in) = 2.31 microg/h; k(out) = 2.04 microg/h; EC(50) = 21.07 mg/l) production, respectively. The inhibitory effect of roxithromycin on production can be adequately described by the indirect response model with an E(max) concentration-effect relationship.