Effect of obesity on rat reproduction and on the development of their adult offspring

K.E Campos,I.M.P Calderon,M.V.C Rudge,D.C Damasceno,G.T Volpato

doi:10.1590/s0100-879x2008005000001

K.E Campos, I.M.P Calderon + Show 3 more

Open Access

https://doi.org/10.1590/s0100-879x2008005000001

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Abstract

The aim of the present study was to assess the reproductive parameters of obese Wistar rats and to determine the frequency of their obese adult offspring. Neonatal rats were divided into two groups: F1 generation, induced to obesity by monosodium glutamate (MSG; F1MSG, N = 30), and rats given saline (F1CON, N = 13). At 90 days of age all animals were mated, producing the F2 offspring (F2CON, N = 28; F2MSG, N = 15). Reproductive parameters (fertility, pregnancy, and delivery indexes) were evaluated in F1 rats. F2 newborns were weighed, and the obesity parameter for F1 and F2 generations was determined from months 5 to 7 of life. At month 7, periovarian fat was weighed and no differences were found. Mean newborn weight also did not differ. The F1 and F2MSG groups presented approximately 90% of obese rats since month 5 of life, whereas F1 and F2CON groups presented only 33%. There was no difference in periovarian weight among groups. Although obesity did not affect reproductive parameters, obese dams (F1MSG) were responsible for the appearance of obesity in the subsequent generation. Thus, obesity induced by neonatal MSG administration did not interfere with reproduction, but did provide a viable model for obesity in second-generation adult Wistar rats. This model might contribute to a better understanding of the pathophysiological mechanisms involved in transgenerational obesity.

Highlights

The negative effects of obesity on reproductive function were first documented more than 2000 years ago by Hippocrates, few scientific investigations of women have dealt with the etiology of this unfavorable condition [1]
In the context of the existing relationship between obesity and complications of female reproduction and considering the interest in hereditary consequences, the objective of the present study aims to evaluate the reproductive parameters of Wistar rats treated with monosodium glutamate (MSG) during the neonatal period and to determine the frequency of their obese offspring
Several indexes were evaluated to estimate female reproductive performance: fertility index was calculated by the number of pregnant females x 100 / number of mated females; delivery index was calculated by the number of delivering females x 100 / number of pregnant females, and pregnancy index was determined by the number of dams with live newborns x 100 / number of pregnant females [10]

Summary

Introduction

The negative effects of obesity on reproductive function were first documented more than 2000 years ago by Hippocrates, few scientific investigations of women have dealt with the etiology of this unfavorable condition [1]. In the context of the existing relationship between obesity and complications of female reproduction and considering the interest in hereditary consequences (transgenerational effect), the objective of the present study aims to evaluate the reproductive parameters of Wistar rats treated with MSG during the neonatal period and to determine the frequency of their obese offspring. All 13 F1CON rats that started the experiment reached adult age and were submitted to mating and 84.6% of them presented a positive diagnosis of pregnancy.

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