Relationship between Na/K-ATPase in thawed sperm and fertility of Angus bulls.

Since bull fertility prediction remains challenging, the identification of potential fertility markers is important considering the economic benefits to the livestock industry. The main goal of this study was to determine the Na/K-ATPase activity and expression in thawed sperm of high (HF)- and low-fertility (LF) Angus bulls. Samples from three different batches/bulls with HF (n = 4) and LF (n = 4) were used. The Na/K-ATPase activity was determined after thawing, whereas sperm kinematics, membrane integrity, and expression of Na/K-ATPase on sperm surface were evaluated immediately post-thaw and after 120 minutes of incubation. Within the same incubation time, there was no difference on sperm membrane integrity, kinematics, and the expression of Na/K-ATPase on the sperm surface between HF and LF bulls. Kinematic parameters of LIN and VCL were not influenced by incubation time in samples from HF and LF, respectively. A tendency (P = 0.06) of higher Na/K-ATPase enzymatic activity for sperm of HF bulls compared to LF bulls was observed (0.49 ± 0.07 and 0.32 ± 0.06, respectively). In conclusion, Na/K-ATPase activity and expression in thawed sperm from Angus bulls are not related to the fertility index after fixed-time artificial insemination. However, sperm kinematics related to hyperactivation might indicate higher sperm cryotolerance for HF bulls.

The cellular prion protein modulates phagocytosis and inflammatory response.

The cellular prion protein (PrPc) is a glycoprotein anchored by glycosylphosphatidylinositol (GPI) to the cell surface and is abundantly expressed in the central nervous system. It is also expressed in a variety of cell types of the immune system. We investigated the role of PrPc in the phagocytosis of apoptotic cells and other particles. Macrophages from mice with deletion of the Prnp gene showed higher rates of phagocytosis than wild-type macrophages in in vitro assays. The elimination of GPI-anchored proteins from the cell surface of macrophages from wild-type mice rendered these cells as efficient as macrophages derived from knockout mice. In situ detection of phagocytosis of apoptotic bodies within the retina indicated augmented phagocytotic activity in knockout mice. In an in vivo assay of acute peritonitis, knockout mice showed more efficient phagocytosis of zymosan particles than wild-type mice. In addition, leukocyte recruitment was altered in knockout mice, as compared with wild type. The data show that PrPc modulates phagocytosis in vitro and in vivo. This activity is described for the first time and may be important for normal macrophage functions as well as for the pathogenesis of prion diseases.

Leaf extract from Clusia nemorosa induces an antinociceptive effect in mice via a mechanism that is adrenergic systems dependent.

Previous studies on the genus Clusia have shown anti-inflammatory and antiproliferative effects of the leaf extracts, but its antinociceptive activity has never been characterized. In the present study, the antinociceptive activity of the hexane extract of the leaves of Clusia nemorosa G. Mey, called HECn, was examined. Antinociceptive activity was evaluated using acetic acid-induced writhing, formalin, and hot-plate tests. All experiments were carried out on male Swiss mice. The extract (1-400 mg·kg(-1)), given by intraperitoneal route (i.p.) 1 h prior to testing, produced a dose-dependent inhibition on the number of abdominal writhings, with an ID50 of 62 mg·kg(-1). In addition, HECn was able to prevent the visceral pain induced by acetic acid in mice for at least 2 h. In the formalin test, HECn had no effect in the first phase, but produced an analgesic effect on the second phase with the inhibition of licking time. The HECn did not show a significant analgesic effect in the hot plate test. Pretreatment with yohimbine attenuated the antinociceptive effect induced by HECn in the writhing test. However, naloxone, atropine, or haloperidol did not affect antinociception induced by HECn in the writhing test. Together, these results indicate that the extract from the leaves of Clusia nemorosa produces antinociception in models of chemical pain through mechanisms that suggest participation of the adrenergic systems pathway.

Methanol extract from mycelium of endophytic fungus Rhizoctonia sp. induces antinociceptive and anti-inflammatory activities in mice.

The present study aimed to elucidate the antinociceptive and anti-inflammatory properties of the methanol extract from the mycelium of the endophytic fungus Rhizoctonia sp. (MEMRh) in mice. The antinociceptive activity was assessed using the abdominal constriction, hot plate, and formalin tests. The anti-inflammatory activity was assessed using a murine model of paw edema. Intraperitoneal administration of MEMRh (0.1, 1, 10 and 100 mg/kg, i.p.) produced an inhibition of acetic acid-induced writhing in mice for at least 8 h. In addition, all doses tested of the methanol extract were able to prevent thermal nociception in the hot-plate test. Furthermore, treatment with MEMRh (10 mg/kg, i.p.) inhibited both the early and late phases of formalin-induced nociception. This antinociceptive effect exhibited by MEMRh in the formalin test was reversed by the systemic administration of naloxone. MEMRh produced inhibition in a carrageenan-induced edema model at a dose of 10 mg/kg. The same extract also displayed significant activity against a histamine- or PGE(2)-induced edema model. The experimental data demonstrated that MEMRh showed remarkable anti-inflammatory and antinociceptive activities. Further studies are warranted to define and isolate the active anti-inflammatory and antinociceptive components from this endophytic fungus, which may yield effective agents for the treatment of inflammatory disorders.