Effects of Maternal Tobacco Smoke or Alpha Lipoic Acid on Puberty Onset, Estrous Cycle and Gonadotropin Levels in Female Rats

Abstract

Various environmental factors are known to affect puberty onset. However, there are few studies in literature about how maternal tobacco smoke (ts) or alpha lipoic acid (ala) affect the hypothalamus-pituitary-gonadal axis at peripheral or central levels in rats. This study aimed to investigate effects of maternal tobacco smoke or alpha lipoic acid on puberty onset, estrous cycle and serum gonadotropin levels in female rats. Adult female spraque-dawley rats were used. All animals were randomly divided into 4 groups (control, ts, ts+ala and ala) and each group consisted of 7 rats. All ts rats were exposed to ts (20 gram\day, for one hour twice a day) and all ala rats received daily oral ala (20 mg/kg) during 8 week. Afterwards all rats were impregnated, ts or ala treatments continued during pregnancy. All treatments ended with birth and later newborn female rats were selected for each group (n=7). Puberty onset was monitored by examination of vaginal opening in female rat pups. Subsequently, estrous cycle was conducted daily for 15 days and determined by examination of the vaginal smear cytology. Also, serum fsh and lh levels were measured using elisa method at the end of the experiment. There was significantly advanced on puberty onset day for ts group (p<0.05). There was a significantly increase in pubertal weight in ala group compared to control group (p<0.001). The mean total number of estrous cycles and average duration of metestrus, diestrus, proestrus or estrus phases were not significantly different in all treatments groups compared to control group. There was no any significant change in serum fsh levels, but serum lh levels were significantly increased in all treatment groups compared to control group (p<0.05). Present study showed that maternal tobacco smoke or alpha lipoic acid may affect hypothalamus-pituitary-gonadal axis differently in rats.