title: Influence of IGF-I on buffalo (Bubalus bubalis) spermatozoa motility, membrane integrity, lipid peroxidation and fructose uptake in vitro.
abstract: The objective of the present experiment was to examine the influence of mean physiological concentration of insulin-like growth factor-I (IGF-I) on frozen-thawed Surti buffalo (Bubalus bubalis) spermatozoa functional parameters, i.e., motility, plasmalemma integrity, acrosomal integrity, functional membrane integrity, lipid peroxidation and fructose uptake in vitro. Frozen-thawed semen samples (n=6) were washed in tris buffer and divided into two equal parts (control and IGF-I groups). Only in the IGF-I group, IGF-I (rhIGF-I analogue) was added to a final concentration of 100 ng/ml. The samples were incubated at 37 degrees C for 2h and the assessments were made at 0, 30, 60, 90 and 120 min of incubation. The mean concentration of the buffalo seminal plasma (n=17) IGF-I was 116.83+/-28.34 ng/ml (range 41.4-198.95). IGF-I had significant effect on the total motility (P<0.01), progressive forward motility (P<0.01), functional membrane integrity (P<0.05) and lipid peroxidation levels (P<0.05) during the 120-min study period as assessed by area under curve. Treatment with IGF-I increased (P<0.01) the total spermatozoa motility at 30, 60 and 90 min as compared to the control. The progressive forward motility was significantly (P<0.01) higher at 60 and 90 min of incubation. The addition of IGF-I resulted in significant (P<0.01) increase in straight-line velocity (VSL, microm/s) as compared to the control at 60 and 90 min of incubation. The linearity (%) was significantly (P<0.01) higher in IGF-I treated semen as compared to control at 60 min of incubation. Plasmalemma integrity in IGF-I group was significantly (P<0.05) higher than control at 30 and 60 min of incubation. The functional membrane integrity differed significantly (P<0.01) between groups (control and IGF-I) at 60 and 90 min of incubation. The percentage of acrosomal intact spermatozoa decreased continuously over a period of time in both the groups. As compared to 0 min of incubation, the significant (P<0.05) loss of acrosome was observed at 60 and 90 min of incubation in control (63.87+/-3.17 vs. 58.52+/-2.54) and IGF-I (61.60+/-2.26 vs. 56.11+/-2.12) groups, respectively. Lipid peroxidation levels were significantly lower in IGF-I group at 90 min (P<0.05) and 120 min (P<0.01) of incubation than the control group. Fructose utilization was significantly higher in IGF-I group as compared to control at 30 min (P<0.05) and 60 min (P<0.01) of incubation. The present study suggests that addition of IGF-I improve spermatozoa functional parameters by reducing lipid peroxidation levels.
authors.affiliation: Animal Physiology Division, National Institute of Animal Nutrition and Physiology, Adugodi, Bangalore 560030, India. selvarajuars@rediffmail.com
authors.forename: S
authors.initials: S
authors.lastname: Selvaraju
authors.forename: I J
authors.initials: IJ
authors.lastname: Reddy
authors.forename: S
authors.initials: S
authors.lastname: Nandi
authors.forename: S B N
authors.initials: SB
authors.lastname: Rao
authors.forename: J P
authors.initials: JP
authors.lastname: Ravindra
mesh_terms: D000818:Animals; D002020:Buffaloes / Q000502:physiology; D002463:Cell Membrane Permeability / Q000187:drug effects*; D004734:Energy Metabolism / Q000187:drug effects / Q000502:physiology; D005632:Fructose / Q000378:metabolism*; D007334:Insulin-Like Growth Factor I / Q000032:analysis / Q000494:pharmacology*; D015227:Lipid Peroxidation / Q000187:drug effects*; D008297:Male; D008315:Malondialdehyde / Q000378:metabolism; D012661:Semen / Q000737:chemistry; D012662:Semen Preservation / Q000379:methods; D013081:Sperm Motility / Q000187:drug effects*; D013094:Spermatozoa / Q000737:chemistry / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure
chemical_list: D005632:Fructose; D008315:Malondialdehyde; D007334:Insulin-Like Growth Factor I