Effects of medium containing heparin and theophylline on capacitation and metabolic enzyme activities of ejaculated spermatozoa from dogs with asthenozoospermia

The percentages of motile sperm (%MO), hyperactivated sperm (%HA), and acrosome-reacted sperm (%AR) of four beagle dogs with asthenozoospermia (AS) and five normal beagle dogs were determined during 7 h of incubation. The metabolic enzyme activities of the sperm was examined after 0 and 4 h of incubation. The sperm were incubated in canine capacitation medium (CCM) and CCM containing either 20 μg ml−1 heparin (HE), 10 μg ml−1 theophylline (TH) or 20 μg ml−1 HE+10 μg ml−1 TH in glass tubes at 38°C under 5% CO2 in air. The %HA and %AR were determined by counting the sperm exhibiting star-spin like movement and by the triple stain technique. The spermatozoa in HE+TH CCM were homogenized and centrifuged, and the metabolic activities of hexokinase, fructokinase, glucose-6-phosphodehydrogenase (G6PD), and pyruvate kinase in the sperm cytosol in the supernatant was measured with a spectrophotometer. The mean %MO and %HA values of both AS and normal dogs in the four types of CCM were highest in HE+TH CCM, with a mean %HA in HE+TH CCM of 78±5% (S.E.) after 7 h of incubation. However, there was little difference in %AR among the four types of CCM. The mean activities of the four enzymes in the sperm of AS dogs before incubation was significantly lower than in the sperm of normal dogs (P<0.05, 0.01). However, after 4 h of incubation the activities of all enzymes in the sperm of both AS and normal dogs was clearly higher in HE+TH CCM than in the control CCM. These findings indicate that HE and TH in the medium are effective in activating metabolic enzymes, maintaining longer sperm motility, and efficiently inducing HA even of the sperm of AS dogs.