title: Exercise protects against obesity induced semen abnormalities via downregulating stem cell factor, upregulating Ghrelin and normalizing oxidative stress.
abstract: Increased oxidative stress and hormonal imbalance have been hypothesized to underlie infertility in obese animals. However, recent evidence suggests that Ghrelin and Stem Cell Factor (SCF) play an important role in fertility, in lean individuals. Therefore, this study aimed at investigating whether changes in the levels of Ghrelin and SCF in rat testes underlie semen abnormal parameters observed in obese rats, and secondly, whether endurance exercise or Orlistat can protect against changes in Ghrelin, SCF, and/or semen parameters in diet induced obese rats. Obesity was modelled in male Wistar rats using High Fat Diet (HFD) 12-week protocol. Eight week-old rats (n=40) were divided into four groups, namely, Group I: fed with a standard diet (12 % of calories as fat); Group II: fed HFD (40 % of calories as fat); Group III: fed the HFD with a concomitant dose of Orlistat (200 mg/kg); and Group IV: fed the HFD and underwent 30 min daily swimming exercise. The model was validated by measuring the levels of testosterone, FSH, LH, estradiol, leptin, triglycerides, total, HDL, and LDL cholesterol, and final change in body weight. Levels were consistent with published obesity models (see Results). As predicted, the HFD group had a 76.8 % decrease in sperm count, 44.72 % decrease in sperm motility, as well as 47.09 % increase in abnormal sperm morphology. Unlike the control group, in the HFD group (i.e. obese rats) Ghrelin mRNA and protein were elevated, while SCF mRNA and protein were diminished in the testes. Furthermore, in the HFD group, SOD and GPx activities were significantly reduced, 48.5±5.8 % (P=0.0012) and 45.6±4.6 % (P=0.0019), respectively, while TBARS levels were significantly increased (112.7±8.9 %, P=0.0001). Finally, endurance exercise training and Orlistat administration individually and differentially protected semen parameters in obese rats. The mechanism includes, but is not limited to, normalizing the levels of Ghrelin, SCF, SOD, GPx and TBARS. In rat testes, diet induced obesity down regulates SCF expression, upregulates Ghrelin expression, and deteriorate oxidative stress levels, which are collectively detrimental to semen parameters. Exercise, and to a lesser extent Orlistat administration, protected effectively against this detrimental effect.
authors.affiliation: Department of Physiology, College of Medicine, King Khalid University, Abha, Kingdom of Saudi Arabia.
authors.forename: Fahaid
authors.initials: F
authors.lastname: Alhashem
authors.affiliation: Department of Physiology, College of Medicine, King Khalid University, Abha, Kingdom of Saudi Arabia.
authors.forename: Mahmoud
authors.initials: M
authors.lastname: Alkhateeb
authors.affiliation: Department of Physiology, College of Medicine, King Khalid University, Abha, Kingdom of Saudi Arabia.
authors.forename: Hussein
authors.initials: H
authors.lastname: Sakr
authors.affiliation: Department of Obstetrics and Gynecology, College of Medicine, King Khalid University, Abha, Kingdom of Saudi Arabia.
authors.forename: Mesfer
authors.initials: M
authors.lastname: Alshahrani
authors.affiliation: Department of Obstetrics and Gynecology, College of Medicine, King Khalid University, Abha, Kingdom of Saudi Arabia.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Alsunaidi
authors.affiliation: Department of Pharmacology, College of Pharmacy, King Khalid University, Abha, Kingdom of Saudi Arabia.
authors.forename: Hesham
authors.initials: H
authors.lastname: Elrefaey
authors.affiliation: Department of Biochemistry, College of Medicine, King Khalid University, Abha, Kingdom of Saudi Arabia.
authors.forename: Riyad
authors.initials: R
authors.lastname: Alessa
authors.affiliation: Department of Biology, College of Science, King Khalid University, Abha, Kingdom of Saudi Arabia.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Sarhan
authors.affiliation: Department of Applied Medical Sciences, College of Health Sciences, PAAET, Kuwait.
authors.forename: Samy M
authors.initials: SM
authors.lastname: Eleawa
authors.affiliation: Division of Physiology, Department of Basic Medical Sciences, Faculty of Medicine, King Saud bin Abdulaziz University for Health Sciences, King Fahad Medical City, Riyadh, Kingdom of Saudi Arabia.
authors.forename: Mohammad A
authors.initials: MA
authors.lastname: Khalil
keywords: Ghrelin; Orlistat; diet induced obesity; exercise; infertility; stem cell factor