Growth performance and fertility of Windsnyer boars supplemented with α-tocopherol.

The purpose of the present work was to determine the response in growth performance and spermatozoa characteristics of Windsnyer boars supplemented with progressive levels of α-tocopherol. Twenty Windsnyer boars aged 12 weeks with an average body weight of 19.5 ± 2.67 kg were used. Each boar was housed individually in a 1.54 × 0.8 m pen in environmentally controlled house with the temperature ranging from 22 to 25 °C. Five boars were randomly assigned to each diet containing 0, 40, 70 and 90 IU of α-tocopherol. The growth performance experiment lasted for 12 weeks. Subsequently, boars were humanely slaughtered for analyses of testicular development and spermatozoa characteristics. Polynomial regression was used to analyse data. There was a linear response (P < 0.05) in average daily gain and feed conversion ratio as α-tocopherol levels increased. Left and right testicular weights showed a linear increase (P < 0.05) with increasing levels of α-tocopherol. Weights of left and right epididymis exhibited quadratic response (P < 0.05). Seminiferous tube area responded in a quadratic fashion (P < 0.05). There was a quadratic relationship (P < 0.05) between semen volume, straight-line velocity and live spermatozoa. Dead spermatozoa and head abnormalities exhibited linear decrease (P < 0.05). In conclusion, inclusion of α-tocopherol improved growth performance and fertility of Windsnyer boars.

Nitric oxide stimulated vascular smooth muscle cells undergo apoptosis induced in part by arachidonic acid derived eicosanoids.

The role of eicosanoids in atherogenesis has not been thoroughly explained. This is partly due to the numerous eicosanoids and the variable effects that each has on different systems. Apoptosis of vascular smooth muscle cells has been shown to play a role in the atherosclerotic disease leading to lesion formation and further destabilization of the formed lesion. In this study, we have investigated the role of arachidonic acid derived eicosanoids in nitric oxide (NO)-stimulated vascular smooth muscle cells. We have shown previously that the nitric oxide (NO)-induced apoptosis of vascular smooth muscle cells was accompanied by arachidonic acid release via cytoplasmic phospholipase A(2) (cPLA(2)) activation. Also, arachidonic acid, but not oleic acid, induced apoptosis of these cells at low concentrations (5-10 microM). Our results revealed that the cPLA(2) specific inhibitor, arachidonyl trifluoromethyl ketone (AACOCF(3)), blocked NO-induced eicosanoid production, while the presence of arachidonic acid enhanced the ability of the cells to make prostaglandin E(2) (PGE(2)). Also, inhibitors of the cyclo-oxygenase (Cox) enzymes, such as N-[2-cyclohexyloxy)-4-nitrophenyl]-methanesulfonamide (NS-398), a specific Cox-2 inhibitor, or indomethacin, a non-specific Cox inhibitor, blocked NO-induced PGE(2) production and apoptosis of vascular smooth muscle cells to the same extent, indicating that apoptosis might be induced by a Cox-2 metabolic product. In addition to these observations, the eicosanoids investigated, namely, PGE(2), PGI(2) LTB(4), and PGJ(2), showed different effects on vascular smooth muscle cells. Both PGJ(2) and LTB(4) decreased the percentage of viable cells and induced apoptosis of vascular smooth muscle cells, while PGE(2) and PGI(2) had no effect on cell viability and failed to induce apoptosis. These data suggest that eicosanoids, such as PGJ(2), but not PGE(2) or PGI(2), are involved in NO-induced apoptosis of vascular smooth muscle cells and that the eicosanoid synthesis pathways might be utilized for vascular therapeutic strategies.

cPLA2 activator peptide, PLAP, increases arachidonic acid release and apoptosis of vascular smooth muscle cells.

Apoptosis of vascular smooth muscle cells (VSMCs) has recently drawn a lot of interest in various laboratories due to its importance in atherogenesis. We have shown previously that nitric-oxide (NO) can induce apoptosis of VSMCs and that the NO-induced apoptosis is accompanied by an increase in arachidonic acid release via cytoplasmic Ca(2+)-dependent phospholipase A(2) (cPLA(2)). We have demonstrated here that NO-induced activation of cPLA(2) leading to increased arachidonic acid release can be mimicked via direct activation of cPLA(2) with a cPLA(2) activator peptide, PLAP. The PLAP induced arachidonic acid release and apoptosis is inhibitable by a cPLA(2)-specific inhibitor, AACOCF(3), indicating the direct involvement of cPLA(2). In this study, activation of cPLA(2) appears to be preceded by activation and binding by PLAP indicating that the cPLA(2) functions are mediated via PLAP.

NO induced apoptosis of vascular smooth muscle cells accompanied by ceramide increase.

We have shown previously that nitric-oxide (NO) can induce apoptosis of vascular smooth muscle cells (VSMCs) and that the NO-induced apoptosis is accompanied by an increase in arachidonic acid release via cytoplasmic Ca(2+)-dependent phospholipase A(2) (cPLA(2)). We have evidence that during NO-induced apoptosis there is an increase in ceramide synthesis. The use of inhibitors of ceramide synthesis, namely, fumonisin B1 and desipramine, which block ceramide synthase and sphingomyelinase, respectively revealed that the ceramide was produced via the sphingomyelinase pathway. Inhibition of acid sphingomyelinase by desipramine was shown to inhibit NO-induced apoptosis while fumonisin B1 failed to inhibit this process. C(2)-ceramide could induce apoptosis in cultured VSMCs. Apoptosis in smooth muscle cells was accompanied by the increased activity of DNA fragmentation factor-40 and the secretion of cathepsin D from the cells. In this study, ceramide appears to function as a mediator of apoptosis.

Arachidonic acid release by cPLA2 may be causally related to NO-induced apoptosis in vascular smooth muscle cells.

Apoptosis has been shown to occur in vascular smooth muscle cells during the development of atherosclerosis. In order to investigate the possible role of arachidonic acid during apoptosis in vascular smooth muscle, we induced apoptosis in cultured rat aortal smooth muscle cells (SMCs) by treatment with either UV (ultraviolet) radiation, tumor necrosis factor-alpha (TNF-alpha) or NO donor drugs (sodium nitroprusside, or S-nitroso-N-acetyl-D-penicillamine, SNAP). Apoptosis was detected by either DNA fragmentation analysis or by TUNEL analysis. UV radiation, TNF-alpha and NO were observed to stimulate apoptosis in the cells as well as to stimulate arachidonate release from the cells. NO also increased levels of cPLA2 in the cells, which is an enzyme that is frequently activated in cells that release arachidonate. These agents stimulated arachidonate release somewhat earlier than they stimulated apoptosis in the cells. The inhibition of cPLA2 by arachidonyl trifluoromethyl ketone (AACOCF3) also led to the inhibition of arachidonate release from the cells as well as the inhibition of nitroprusside stimulated apoptosis. Arachidonic acid itself could induce apoptosis in the cultured cells. These observations provide evidence that arachidonate may be involved in apoptosis in vascular smooth muscle.