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

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: F 1 generation, induced to obesity by monosodium glutamate (MSG; F 1 MSG, N = 30), and rats given saline (F 1 CON, N = 13). At 90 days of age all animals were mated, producing the F 2 offspring (F 2 CON, N = 28; F 2 MSG, N = 15). Reproductive parameters (fertility, pregnancy, and delivery indexes) were evaluated in F 1 rats. F 2 newborns were weighed, and the obesity parameter for F 1 and F 2 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 F 1 and F 2 MSG groups presented approximately 90% of obese rats since month 5 of life, whereas F 1 and F 2 CON groups presented only 33%. There was no difference in periovarian weight among groups. Although obesity did not affect reproductive parameters, obese dams (F 1 MSG) 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. Although 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). Obesity is rapidly growing among women in general and women of fertile age (2). Clinical investigations show that obese women have a greater prevalence of amenorrhea and infertility. It is common to find greater risks of complications during pregnancy among these women such as hypertension, gestational diabetes and greater susceptibility to complications during delivery, which result in unplanned cesarean surgeries. Maternal obesity can have a negative effect on children's health (3).Since it is difficult to determine obesity-induced reproductive complications in women, experimental studies are carried out to induce obesity. The model of neonatally monosodium glutamate (MSG)-treated rats is of special interest regarding the development of obesity (4-6). Neonatal treatment with MSG has been shown to destroy hypothalamic arcuate nucleus neurons, resulting in several endocrine disturbances (7), stunted growth, and obesity (8).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.Wistar rats were kept in collective cages under con-

Reproductive alterations in hyperinsulinemic but normoandrogenic MSG obese female rats

“…Our MSG rats exhibited irregular estrous cycles, which reinforces previous findings (Nagasawa et al 1974, Lamperti & Blaha 1976, Lorden & Caudle 1986, Campos et al 2008 and supports the connection between MetS and reproductive disorders. The MSG rats had lighter ovaries when compared with CTR, explained by deficient GH pulsatile secretion.…”

“…Besides metabolic repercussions, MSG rodents show impaired reproductive parameters associated with dysfunctional HPG axis (Lamperti & Baldwin 1983, Dada & Blake 1985, Rose & Weick 1987, Franca et al 2006. Albeit not being sterile, as initially suggested (Olney 1969), MSG female rodents exhibit reduced ovarian weight (Lamperti & Blaha 1976), longer estrous cycle (Nagasawa et al 1974), delayed puberty (Lorden & Caudle 1986), and reduced fertility (Campos et al 2008). However, ovarian morphology of MSG rodents has deserved little attention in the literature.…”

Potensi Suplementasi Resveratrol dalam Mengatasi Efek Negatif Hormon Tiroid pada Terapi Obesitas: Uji Preklinik

“…Setelah adaptasi selama 1 minggu, dilakukan induksi obesitas dengan pemberian diet tinggi lemak (49,2% kalori dari lemak) dan propiltiourasil (PTU) 0,01% 0,5 mg/kgBB selama 10 minggu. Hewan coba dikatakan obesitas jika tercapai Indeks Lee >0,3 yang dihitung dengan rumus sebagai berikut: 7 Gambar 1 menunjukkan hewan coba sebelum dan sesudah induksi obesitas, sedangkan Gambar 2 memperlihatkan cara pengukuran panjang badan nasoanal untuk menghitung Indeks Lee. Terhadap hewan coba yang memenuhi kriteria obesitas dilakukan pengambilan sampel darah melalui vena ekor untuk mendapatkan data awal resistensi insulin {melalui pengukuran area under the curve (AUC) glukosa} dan kondisi stres oksidatif {berupa kadar malondyl aldehyde (MDA) plasma dan kerusakan DNA}.…”

Production and Potency of Local Rambutan at East Java as a Candidate Phytopharmaca

“…Obese rats were fed with a high calorie diet. Criteria of obese rats based on the Lee Index criteria (Campos, et al, 2008). The rats were divided into six treatment groups, non-treatment (NT), ellagic acid (EA 15 μg/kg BW), placebo (water and corn oil), and three different dose of rambutan peel extracts (RPE: 15 mg/kg BW, 30 mg/kg BW, and 60 mg/kg BW).…”