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| Author(s): |
Ana Paula Alves Favareto
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia |
| Defense date: | 2008-02-21 |
| Examining board members: |
Wilma De Grava Kempinas;
Eliana Milanesi Rubio;
Marcelo Fabio Gouveia Nogueira
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| Advisor: | Wilma De Grava Kempinas |
| Abstract | |
Several studies have shown that the SP22 sperm membrane protein (22-28 kDa) is highly correlated with fertility. The location of this protein on the equatorial segment of the sperm head in several mammallian species, and the inhibition of in vivo and in vitro fertilization, obtained by the incubation of spermatozoa with anti-rSP22 antibodies, suggest its paticipation in spermatozoon-oocyte interaction and its importance for the male reproductive capacity. Thus, the goals of the present study were to evaluate the presence of the SP22 protein on spermatozoa from adult rams (Dorper and Santa Inês breeds), identifying its location; to quantify the levels of this protein by ELISA and FITC immunostaning analysis using anti-rSP22 Ig; and to correlate its levels with sperm parameters of morphology, membrane integrity evaluated by fluorescent probes (carboxyfluorescein diacetate and propidium iodide) and kinetics by computer-assisted sperm analysis (CASA). The SP22 was specifically located on the equatorial segment of the head and neck of the ram spermatozoon. The ELISA and FITC immunostaning techniques appear to be efficient for the SP22 quantification in ovine spermatozoa and were significantly correlated (R2 = 0.70). There was no significant difference (P > 0.05) in SP22 levels assessed by these two methods between the studied breeds. For the study of the sperm kinetics, multivariate statistical analysis was performed, considering the individual values obtained by CASA system (1 ejaculate per ram, n = 3847 spermatozoa). Through clustering analysis, it was possible to set up a number of 3 sperm subpopulations coexistent within ejaculate from rams. The subpopulation 1 was the most active and progressive. The subpopulation 3 had little progressive and non-linear movement and the subpopulation 2 had an intermediate kinetic pattern. There was significant difference (chi-square = 824.39; degrees of freedom = 34; P < 0.0001) in the distribution of the 3 subpopulations among the rams. However, there was no significant correlation (P > 0.05) between the proportion of each subpopulation in the rams and the SP22 levels evaluated by ELISA and FITC immunostaining analysis. The membrane integrity was positively correlated (R2 = 0.48; P = 0.02) with the proportion of spermatozoa in subpopulation 1 and it was negatively correlated (R2 = 0.30; p = 0.02) with subpopulation 3. However, this sperm parameter was not significantly correlated (P > 0.05) with proportion of spermatozoa in subpopulation 2. Moreover, sperm morphology was not significantly correlated (P > 0.05) with the proportions of the three kinematics subpopulations found within ejaculate semen. The SP22 levels obtained by ELISA were negatively and positively correlated (R2 = 0.47 for 3 variable) with percentages of spermatozoa morphologically abnormal and of spermatozoa with intact plasma membrane, respectively. The SP22 quantification by FITC immunostaning analysis was no correlated with any of the sperm parameters. These results showed that study of the SP22 protein in ram spermatozoa can bring important information about the reproductive capacity of these animals. Nevertheless, studies that correlate the SP22 levels with in vivo and/or in vitro fertility rate are necessary for validation of this protein as a fertility biomarker in this species (AU) | |