All the slides were read blind selleckchem FTY720 with coded samples under Nikon Eclipse 80 i epifluores cence microscope using an oil immersion objective. Two hundred sperm were scored for every spot and the percentage of acro some reaction was calculated by dividing the number of acrosome reacted sperm by the total number of sperm counted and multiplied by hundred. Induction of acro some reaction at an optimized dose of SIZP was evalu ated using semen samples from si different donors. Intracellular calcium estimation Changes in i were analyzed with the fluorescent probe Fluo 3 aceto ymethyl ester. Capacitated sperm were loaded with 2 uM fluo 3 AM containing 1 uM pluronic acid F 127 for 1 hr at 37 C with 5% CO2 in air. Labelled sperm were then kept for half an hour at 37 C with 5% CO2 in air for de esterification of dye.

Labelling and de esterification of Fluo 3 AM in capacitated sperm was performed in BWW medium whereas assay was performed in BWW medium supplemented with 0. 3% BSA. Capacitated sperm were added in 96 well black plates. The baseline fluorescence measurements were performed at an e citation wavelength of 480 nm and an emission of 520 nm for 200 sec followed by addi tion of SIZP and continued fluorescence measurements for ne t 10 minutes. The i was calculated by using the Grynkiewicz equation i Kd , Brefeldin_A where Kd is the dissociation constant of the Ca2 fluo 3 comple , and F represents the fluorescence intensity of the cells. Fma represents the ma imum fluorescence and Fmin corresponds to the mini mum fluorescence.

Ca2 levels have been presented as the change in intracellular calcium, i by calculating selleck difference between peak i and resting i before stimulation. Resting i represent the average of sperm i for 200 sec preceding SIZP addition. All measurements were carried out in a Fluostar Optima Spectrofluorimeter. Delineation of voltage operated calcium channels associated with SIZP mediated release of i and acrosome reaction To delineate the involvement of different type of Vol tage Operated Calcium Channels during SIZP mediated induction of acrosome reaction, 1 106 capa citated sperm were pre treated with Pimozide or Mibefradil as T Type Ca2 channel blocker, Verapamil or Nifedipine as L Type CCB. for 10 min at 37 C with 5% CO2 in humidified air prior to the addi tion of SIZP. The concentrations of the various inhibi tors employed in these e periments were based on previously published studies and inhibitors were procured from Sigma Aldrich Inc. In addition, effect of prior treatment of capacitated human sperm with Pimozide and Verapamil on the levels of i in response to SIZP were also determined by fluorimetric assay as described above.