ABSTRACT
Objective To explore the adjustment effects of suckling nutrition on hypothalamus gonadotropin-releasing hormone neurons(GnRH) expression level and adolescence sexual development by establishing different nutrition models for suckling female rats.Methods One-day-old female Sprague-Dawley rats were randomly assigned to 3 groups.Two suckling rats were fed by one lactation rat in overnutrition group,10 suckling rats were fed by one lactation rat in normal control group,20 suckling rats were fed by one lactation rat in malnutrition group.The animals were weaned at day 21 of age in groups of 5 rats per cage with free access to pelleted food and tap water.To comparatively observe vaginal opening,10 rats in each group were randomly sacrificed when the overnutrition rats showed complete vaginal opening and when the normal control rats showed complete vaginal opening.The amount and percentage of the positive GnRH neurons in hypothalamus arcuate nucleus were detected with immunohistochemistry.The influence of suckling nutrition to female rats adolescence sexual development was assessed by statistical analysis.Results 1.When the overnutrition rats showed complete vaginal opening(at 35-day-old),the amount of positive GnRH neuron in hypothalamus arcuate nucleus was respectively 247?111 in overnutrition group,143?73 in normal control group and 74?70 in malnutrition group.It was showed that the amount of the positive GnRH neuron of hypothalamus arcuate nucleus in overnutrition group was more than the other groups(Pa0.05).3.Overnutrition female rats showed complete vaginal opening at a mean age of (29.60?1.96) days,(39.10?1.66) days in normal control female rats and (41.30?3.33) days in malnutrition female rats.It was proposed that the sexual development of overnutrition rats was earlier than the other groups(Pa