Intracellular calcium movements of boar spermatozoa during 'in vitro' capacitation and subsequent acrosome exocytosis follow a multiple-storage place, extracellular calcium-dependent model

This work analysed intracellular calcium stores of boar spermatozoa subjected to 'in vitro' capacitation (IVC) and subsequent progesterone-induced acrosome exocytosis (IVAE). Intracellular calcium was analysed through two calcium markers with different physico-chemical properties, Fluo-3 and Rhod-5N. Indicative parameters of IVC and IVAE were also evaluated. Fluo-3 was located at both the midpiece and the whole head. Rhod-5N was present at the sperm head. This distribution did not change in any of the assayed conditions. Induction of IVC was concomitant with an increase in both head and midpiece Ca(2+) signals. Additionally, while IVC induction was concurrent with a significant (p < 0.05) increase in sperm membrane permeability, no significant changes were observed in O2 consumption and ATP levels. Incubation of boar spermatozoa in the absence of calcium showed a loss of both Ca(2+) labellings concomitantly with the sperm's inability to achieve IVC. The absence of extracellular calcium also induced a severe decrease in the percentage of spermatozoa exhibiting high mitochondrial membrane potential (hMMP). The IVAE was accompanied by a fast increase in both Ca(2+) signalling in control spermatozoa. These peaks were either not detected or much lessened in the absence of calcium. Remarkably, Fluo-3 marking at the midpiece increased after progesterone addition to sperm cells incubated in a medium without Ca(2+) . The simultaneous addition of progesterone with the calcium chelant EGTA inhibited IVAE, and this was accompanied by a significant (p < 0.05) decrease in the intensity of progesterone Ca(2+) -induced peak, O2 consumption and ATP levels. Our results suggest that boar spermatozoa present different calcium deposits with a dynamic equilibrium among them and with the extracellular environment. Additionally, the modulation role of the intracellular calcium in spermatozoa function seems to rely on its precise localization in boar spermatozoa.

Cryotolerance of stallion spermatozoa is related to ROS production and mitochondrial membrane potential rather than to the integrity of sperm nucleus

Although cryopreservation of stallion spermatozoa allows long-term preservation of spermatozoa from particular stallions and facilitates international trade, it is understood to inflict damages on sperm cells that may finally reduce their fertilizing ability. In addition, individual differences are known to exist in the sperm ability to withstand freeze-thawing protocols. To date, these differences have mainly been reported on the basis of sperm motility and membrane integrity. For this reason, the present work sought to determine differences between good (good freezability ejaculates: GFE) and poor (poor freezability ejaculates: PFE) freezability stallion ejaculates in other sperm parameters, including peroxide and superoxide levels, potential of mitochondrial membrane and nuclear integrity. With this purpose, a total of 24 stallion ejaculates were cryopreserved and classified into two groups (GFE vs. PFE), depending on their sperm membrane integrity and motility after freeze-thawing. From the total of 24 ejaculates, 13 were classified as GFE and the other 11 were classified as PFE. Apart from differences in sperm membrane permeability and lipid disorder after freeze-thawing, GFE presented significantly (p < 0.05) higher percentages of viable spermatozoa with high content of peroxides and of superoxides than PFE. In contrast, and despite cryopreservation of stallion spermatozoa increasing DNA fragmentation and disrupting disulphide bonds in sperm head proteins, no significant differences between GFE and PFE were seen. We can thus conclude that good and poor freezability stallion ejaculates differ in their reactive oxygen species levels after cryopreservation, but not in the damage extent on sperm nucleus.

Decrease in oxidative stress and histological changes induced by physical exercise calibrated in rats with osteoarthritis induced by monosodium iodoacetate

OBJECTIVE

The purpose of this study was to evaluate the effects of impact exercise on the joint cartilage of rats with osteoarthritis (OA) induced by monosodium iodoacetate (MIA).

METHODS

Eighteen male rats were divided into three groups of six animals each: control, OA, and OA plus exercise (OAE). The OAE group trained on a treadmill for 8 weeks. Afterward, the right joints of the animals were washed with saline solution and joint lavage was used for biochemical analyses of myeloperoxidase (MPO) and enzyme superoxide dismutase (SOD) activities and total thiol content. The same limb provided samples of the articular capsule for analyses of MPO activity and total thiol content. The left joint was used for histological analysis.

RESULTS

Our results indicate that MPO activity was increased in both OA groups in the lavage as well as the articular capsule, regardless of exercise status. SOD activity was increased in animals with OA, especially in the animals that had run on the treadmill. On the other hand, thiol content in the articular capsule and joint lavage decreased in the OA group, while the OAE group had values similar to those of the control group. The histological data indicate that animals that were submitted to running exercise showed a higher preservation rate of proteoglycan content in the superficial and intermediate areas of the joint cartilage.

CONCLUSION

Our results show that physical training contributes to the preservation of joint cartilage in animals with OA and to increase the defense mechanism against oxidative stress.

The effect of the Rochagan on radiolabeling with (99m)Tc

Radionuclides are used in nuclear medicine by variety of diagnostic procedures. The labeling of red blood cells (RBC) with (99m)Tc is a current method applied in clinical nuclear medicine. Drugs can alter this labeling and modify the disposition of the radiopharmaceuticals. The influence of Rochagan on the labeling of blood constituents with (99m)Tc was reported. Samples of blood were incubated with different concentrations of Rochagan (0%; 6.25%; 12.5%; 25%; 50%; 100%). Stannous chloride and (99m)Tc (3.7MBq/mL) were added. Plasma (P) and (RBC) were isolated and precipitated with thricloroacetic acid 5%. The insoluble (IF) and soluble fractions (SF) were separated. The %ATI in RBC, IF-P and IF-RBC were calculated. The %ATI on RBC decreased significantly (p<0.05) from control to all concentrations of Rochagan, respectively: 90.15 + or - 0.14(control) to 70.80 + or - 4.21; to 64.36 + or - 0.33; to 57.30 + or - 1.56; to 50.28 + or - 2.71; to 42.41 + or - 2.24; on IF-RBC, respectively: 84.70 + or - 0.87(control) to 67.16 + or - 4.38; to 63.63 + or - 2.92; to 59.02 + or - 3.17; to 43.75 + or - 1.00; to 24.15 + or - 0.94 and also on IF-P, respectively: 83.46 + or - 1.09(control) to 50.90 + or - 3.36; to 35.46 + or - 4.13; to 35.78 + or - 2.31; to 28.74 + or - 3.09; to 19.66 + or - 1.34. The analyses were performed by T-Student and Mann Whitney tests, p<0.05. This effect was probably due to products present in Rochagan that may complex with ions or have a direct/indirect effect on intracellular stannous ion concentration.

Effect of therapeutic pulsed ultrasound on parameters of oxidative stress in skeletal muscle after injury

Contusion injuries are a very common form of both athletic and non-athletic injury, that effect muscle function. Treatments to augment the normal repair and regeneration processes are important for a wide variety of patients. Therapeutic ultrasound has been claimed to promote tissue repair, especially by enhancing cell proliferation and protein synthesis. The present study aimed to investigate the effect of therapeutic pulsed ultrasound (TPU) on parameters of oxidative stress, namely thiobarbituric acid-reactive substances (TBARS), protein carbonyl content and the activities of antioxidant enzymes, catalase and superoxide dismutase (SOD), in skeletal muscle after injury. Wistar rats were submitted to an animal model of muscle (gastrocnemius) laceration. TPU was used once a day. One, three or five days after muscle laceration, the animals were killed by decapitation and oxidative stress parameters were evaluated. Serum CK levels were increased in muscle-injured animals, indicating that the laceration animal model was successful. TBARS were not altered after muscle injury, when compared to the sham group. Protein carbonyl content was increased after muscle laceration. Catalase and SOD activities were increased 1 day after muscle injury and not altered at days 3 and 5. TPU decreased TBARS levels after muscle laceration when compared to injured muscle animals without treatment. Protein carbonyl content evaluation presented similar results. It is tempting to speculate that TPU seems to protect the tissue from oxidative injury. TPU diminished catalase and SOD activities, especially on the first day following muscle laceration.

A review of natural products with antileishmanial activity

Infections caused by protozoa of the genus Leishmania are a major worldwide health problem, with high endemicity in developing countries. The incidence of the disease has increased since the emergence of AIDS. In the absence of a vaccine, there is an urgent need for effective drugs to replace/supplement those in current use. The plant kingdom is undoubtedly valuable as a source of new medicinal agents. The present work constitutes a review of the literature on plant extracts and chemically defined molecules of natural origin showing antileishmanial activity. The review refers to 101 plants, their families, and geographical distribution, the parts utilized, the type of extract and the organism tested. It also includes 288 compounds isolated from higher plants and microorganisms, classified into appropriate chemical groups. Some aspects of recent antileishmanial-activity-directed research on natural products are discussed.