Carmelinda Trisolini

Reactive Oxygen Species (ROS): involvement in bovine follicular cysts etiopathogenesis

Ovulation is compared to an acute inflammatory process during which vasoactive agents, prostanoids, leukotrienes and Reactive Oxygen Species (ROS) develop. The aim of this study was to evaluate the levels of ROS in cystic and follicular fluid, in order to establish their involvement in the etiopathogenesis of Cystic Ovarian Follicle (COF) in dairy cows. The study was conducted in 30 healthy cows (group C) and 30 cows affected by COF (group COF). The fluid of follicular cysts and of preovulatory follicles was drawn by means of ultrasound guided aspiration from the cows of both groups. The fluid obtained was analyzed by a photometric analytical system to detect ROS level. ROS concentration was statistically lower in the cystic fluid than in the follicular one (62.4 ± 13.36 U.Carr vs. 84.89 ± 26.99 U.Carr) (p<0.05), thus suggesting that an alteration of the cascade responsible for ROS production may be implicated in the complex etipathogenesis of COF.

First Demonstration of an Increased Serum Level of Reactive Oxygen Species During the Peripartal Period in the Ewes

Reactive Oxygen Species (ROS) are produced during oxidative metabolism, and regulate many biological processes. The acute inflammation characterizing parturition induces many physiological changes. Among them, there is evidence that ROS affect the synthesis of many factors involved in parturition. Our study aims to determine serum levels of ROS in periparturient ewes, as well as to establish a value of reference of their physiological concentration. ROS determination was performed on blood collected every 12 hours in periparturient twin pregnant ewes. Our results will show a significant increase in ROS concentrations from the beginning to the end of the experiment. This increase may be due to the inflammatory process establishing during parturition.

Renin and ovarian vascularization in cows with follicular cysts after epidural administration of a GnRH analogue

The ovarian renin-angiotensin system may play an important role in follicular growth and maturation, as well as in the process of ovulation. The aim of this study was to investigate the effects of administration of a GnRH analogue to cows with ovarian follicular cysts on plasma renin concentrations and ovarian vascularization. This study was performed with 60 Friesian cows, which were diagnosed with follicular cysts, and randomly allocated into two groups: group A (treatment; n=30) received 2ml of lecirelin (Dalmarelin((R)) - Fatro), per head via sacro-coccygeal epidural, and group B (control; n=30) received 2ml saline solution (0.9% NaCl) per head by the same route. Blood samples were immediately collected prior to administration (T0) and then 24h (T1), 48h (T2) and 8 days (T3) after administration of the treatment, for both groups. Ovarian vascularization was evaluated utilizing Power Doppler on these same days in 10 animals from each group. The number of pixels detected by Power Doppler was used as an indicator of the degree of vascularization. Plasma renin concentrations remained relatively constant for the control (group B) animals, but increased as the sampling period progressed (NS) for the treated cows (group A). Similarly, there were no changes in ovarian vascularization (number of pixels) for the control cows, but vascularization increased throughout the sampling period in the treated animals. The number of pixels associated with cysts was significantly higher for treated compared to control cows at 24h after treatment (P<0.001). The epidural administration of a GnRH analogue was determined to be a highly effective therapy for follicular cysts (regression occurred in 82% of treated cows within 8+/-2 days after treatment, but in none of the control cows), which also enhanced ovarian vascularization.

Blood and milk oxidative status after administration of different antioxidants during early postpartum in dairy cows.

This paper describes serum and milk oxidative profiles during early postpartum (10th-16th day) of dairy cows, after three different treatments: β-carotene and α-tocopherol (Dalmavital®, Fatro, Italy) (VAE Group); L-carnitine, d, L-acetylmethionine, cyanocobalamin (Adiuxan®, Ceva Vetem, Italy) (LCAR Group) and Dalmavital®+Adiuxan® (VAE/LCAR Group). Antioxidant administrations resulted in a general reduction in ROS concentrations which decreased more after a single drug administration (VAE and LCAR Groups) vitamin A and E serum levels increased in the three treated groups compared to control one (p < 0.05). Milk lipoperoxide content was statistically lower in treated cows than in control ones, whereas, as to vitamins, only vitamin E increased in all the treated groups compared to control. Taken together, the results of this study confirm the efficacy of antioxidant administration in the early postpartum of dairy cows and suggest that an excess in antioxidant administration may result, paradoxically, in an increase in ROS generation.

Uterine contractility is strongly influenced by steroids and glucose metabolism: an in vitro study on bovine myometrium

Background. Energetic substrates and hormonal phase are important for uterine contractions. Etomoxir a muscle carnitine palmitoyltransferase-1 inhibitor, able to diverge uterine metabolic pathways towards glycolysis, facilitates glucose utilisation. The aim of this study was to evaluate its effect on uterine contractility in different hormonal situations. Methods. Uterine samples were collected from 60 cows during follicular phase, luteal phase and pregnancy. The cows were slaughtered at a local abattoir. Longitudinal strips were mounted vertically in a 30-ml organ bath connected to an isometric force transducer. Contractions were recorded with an ink-writing polygraph. After the equilibration period, etomoxir was added to the organ bath at different concentrations. The amplitude and frequency of contractions were registered before and after addition of etomoxir. Results. In 17 strips from pregnant cows, etomoxir increased the amplitude (p < 0.05) of contractions but not the frequency in comparison with basal conditions. In 15 strips from cows in the luteal phase, etomoxir increased the amplitude (p < 0.05) and frequency of contractions (p < 0.05 at 5 μM and p < 0.01 at 8 and 10 μM). In 18 strips from cows in the follicular phase, etomoxir increased the frequency of contractions but not the amplitude (p < 0.01 at 5 μM and p < 0.05 at 8 and 10 μM). Conclusions. This study confirms the importance of glucose for uterine contractility and, moreover, it underlines different patterns of contraction with regard to the hormonal status.

Serum levels of reactive oxygen species (ROS) in the bitch

Abstract The aim of this study was to determine the serum concentrations of reactive oxygen species (ROS) during the different phases of the estrous cycle in the bitch, in order to establish their physiological values. 56 healthy mixed-breed bitches were enrolled at this purpose and divided into 4 groups, standing on the different phases of the estrus cycle. Blood samples were collected in all groups and serum ROS concentrations were determined. Proestral concentrations were statistically higher than anestral ones, and statistically lower than those found in estrus (p<0.001). The highest concentrations of ROS were detected at estrus, that is, in the peri-ovulatory period. This sharp increase in ROS concentrations is related to the acute inflammatory process underlying ovulation and to the increase in immune and metabolic activities, cytological changes and myometrial contractility promoted by the high levels of estrogens. In diestrus, the mean concentration of ROS decreases. This reduction did not show any statistically significant difference with the mean value observed in proestrus. In this phase, in fact, the high concentrations of progesterone, exerting an antioxidant and immunodepressive effect, justify the lower mean concentration of ROS detected. In anestrus, the lowest concentrations of ROS were observed, for the reduced metabolic and endocrine activity occurring in this phase of the estrous cycle. In conclusion our results establish the physiologic levels of ROS during the estrous cycle in the bitch and reflect the endocrine morphologic and metabolic changes occurring during it.

Effects of antibiotics on biochemical parameters, leukocytes and Reactive Oxygen Species (ROS) in bitches after ovariectomy

It is well known that following surgical procedures, a variety of patho-physiological alterations occurs in the host, such as changes in haemodynamic, endocrine and immune functions, as well as increase in Reactive Oxygen Species (ROS). Antibiotic administration, a common practice used in surgery, affects immune functions and ROS generation. Our study was aimed to investigate the effect of five different antibiotic regimens: amoxicillin, benzylpenicillin/dihydrostreptomycin, sulfametazine/sulfamerazine/ sulfathiazole, enrofloxacin, lincomycin/spectinomycin, administered twice (2 hours before skin incision and 6 hours after the end of the surgical suture), on biochemical parameters, leukocytes and ROS concentrations, in bitches undergoing open laparotomic ovariectomy. All treated bitches recovered from surgery without developing either systemic dysfunctions, or infections at the surgical site. Mean healing time was 7 ± 3 days. An increase in white blood cell count, in differential leukocyte count and in ROS concentrations occurred 24 hours after the end of surgery, followed by a gradual decrease to basal values within the fourth day after surgery. The biochemical parameters remained quite constant throughout the study. In conclusion, our results show that the above antibiotic regimens, administered only twice, are efficient in inducing an uneventful recovery after laparotomic ovariectomy and preventing the development of infections in the bitch.

Influence of antibiotic therapy on serum levels of reactive oxygen species in ovariectomized bitches

This study was conducted on 60 ovariectomized bitches. The objectives were to measure the mean reactive oxygen species (ROS) concentrations before, during and after surgery, and to investigate the effect of the administration of five different antibiotic treatments: amoxicillin, benzylpenicillin/dihydrostreptomycin, sulfametazine/sulfamerazine/sulfathiazole, enrofloxacin, lincomycin/spectinomycin. The first value recorded represented the mean ROS concentration in anestral bitches and constitutes a reference level with which to compare the subsequent measurements. After premedication, induction of anesthesia and during maintenance and surgery, ROS serum concentrations showed constant values until the end of surgery. After surgery and during antibiotic administration, an increase in ROS concentration occurred, which differed among the five groups in relation to the antibiotics employed. The lowest increases occurred in the groups treated with the combination of lincomycin/spectinomycin, and with amoxicillin; whereas the highest increases were detected in the group treated with enrofloxacin. The three other antibiotics showed an intermediate level of influence on oxidative status.

The expression of leptin receptor in the ovary of the queen: Leptin receptor expression in queen ovary.

Leptin is a Ob gene product secreted mainly by adipose tissue. Several reports showed leptin production by other tissue including the ovary. The action of leptin is mediated upon binding to its receptor widely expressed in reproductive tissues in different species. In fact, there are growing evidences that leptin plays an important role in the modulation of reproductive functions. Therefore, the aim of this study was to evaluate in the queen, the expression of leptin receptor during the functional ovarian cycle and pregnancy. We found that the ovaries of the queen express leptin receptor in all the examined phases. The highest leptin receptor expression was found in the luteal phase (pseudopregnancy, pregnancy) compared to other phases of the cycle (anestrus, proestrus, estrus). The variations in the expression of leptin receptor suggest a likely implication of leptin in the modulation of ovarian activity, in the examined species.

Leptin and queen ovary: new insights about ovulation.

Leptin has been proven to be crucial in the ovulatory process. Aims of this study are to assess the expression of leptin receptor (Ob-R) in the ovaries of queens at estrus and to evaluate the capability of leptin in modulating ovarian contractility in vitro. Right ovaries underwent immunoblot analysis. Left ovaries were mounted in an organ bath under physiological condition and exposed to murine leptin (10(-6) M). Immunoblot analysis showed that the queen ovary expresses leptin receptor at estrus. Leptin at the dose of 10(-6) M significantly reduced the contractile activity of the ovary. The presence of ovarian Ob-R and leptin inhibitory effects on ovarian contractility suggest leptin implication in the modulation of ovarian activity, as well as in ovulatory disorders.