This study evaluated the effect of adding different concentration of cholesterol-loaded-cyclodextrin (CLC) on sperm quality after thawing. Thirty ejaculates were diluted, centrifuged and resuspended to 120 million cells/mL in a Tris diluent. Semen was treated with 0 (Control), 0.75, 1.5, 3.0, 4.5, 6.0 or 7.5 mg of CLC. Then, the samples were cooled at 4 °C for 2 h, diluted with Tris-egg yolk and 2% glycerol, packaged into 0.5 mL straws, frozen in liquid nitrogen (N 2 ) vapor for 20 min before being plunged into N 2 . Straws were thawed at 37 °C for 30 sec, and evaluated for thermal resistance test (TRT); progressive motility using CASA; hypoosmotic test and for binding capacity of sperm to perivitelline membrane (PM). The variables were determined using ANOVA at 5% probability. Higher percentage of motile sperm were maintained after thawing and TTR when 0.75 mg CLC was added, evaluated at 0, 60 and 120 min of incubation (50.4, 33.8 and 22.5%, respectively) compared to other treatments (P<0.05). The percentage of coiling was higher in sperm treated with 6.0 and 7.0 mg of CLC than other treatments (P<0.05). Addition of 0.75 mg CLCs also resulted in more sperm binding to the PM after cryopreservation than control sperm (166 vs 65; P<0.05). However, when the spermatozoa binding potential was determined on a motile sperm basis by dividing the average number of spermatozoa bound to PM for each bucks by the percentage of motile spermatozoa, CLC treatment provided higher binding efficiency (1.52) than control (1.00; P<0.05). In conclusion, CLCs improved the percentage of post-thaw of motility in caprine sperm as well as increased the number of sperm that bind to PM. Addition of 0.75 mg of CLC to caprine sperm prior to cryopreservation improved the quality sperm motility for up to 2 h.Keywords: cyclodextrin, frozen, membrane, spermatozoa, seminal quality.
ResumoEste estudo teve como objetivo avaliar o efeito da adição do colesterol carreado com a ciclodextrina (CCC) sobre a melhoria da qualidade espermática após a descongelação. Trinta ejaculados foram diluídos, centrifugados e ressuspendidos com Tris para concentração de 120 x 10 6 células/mL. O sêmen foi tratado com 0, 0,75, 1,5, 3,0, 4,5, 6,0 ou 7,5 mg de CCC. Em seguida, as amostras foram resfriadas a 4°C durante 2 horas, diluídas com Tris-Gema de ovo e 2% de glicerol, envasadas e colocadas sobre o vapor do nitrogênio líquido (N 2 ) por 20 min e depois mergulhadas no N 2 . As amostras foram descongeladas a 37°C por 30s, e avaliadas quanto: o teste de termorresistência (TRT); motilidade progressiva utilizando CASA; teste hiposmótico e a capacidade de ligação dos espermatozoides à membrana perivitelina (MP). As variáveis foram analisadas por meio da ANOVA e os tratamentos comparados a 5% de probabilidade. A motilidade dos espermatozoides (50,4; 33,8 e 22,5%) foi maior nas amostras tratadas com 0,75 mg de CCC após 0, 60 e 120 min de incubação quando comparado com demais tratamentos (P<0,05). As amostras tratadas com 6,0 e 7,0 mg de CCC apresentaram maior dobram...