| Objective: The aim of this study was to explore the effects of lactating mice exposure to sulfamonomethoxine(SMM) on endocrinology, muscle and brain development, and the exploratory, anxiety and cognitive behaviors of their offsprings. Finally,it was discussed that if the m TOR signaling regulated the above functions.Methods: The lactational mice were orally administered with SMM(0, 10, 50, 200 mg/kg) for 21 days, and then their offsprings were separated with gender, raised normally until postnatal 63 days(PND63), weighing once every week. The body length and head circumference were determined during lactation. Some of the offsprings were sacrificed when they weaned, collected serum and main organs, measuring the gastrocnemius muscle, liver, kidney and brain weights, then calculated the organ coefficient. The behavioral tests involved in open-field test, black-white alley, elevated plus maze and Morris water maze, began at PND 50. The growth hormone(GH), insulin(INS), triiodothyronine(T3), thyroxine(T4), corticosterone(COR), adrenocorticotropic hormone(ACTH) and estradio(E2) concentration in serum were detected by radioimmunoassay and the insulin-like growth factor-1(IGF-1) was detected via enzyme-linked immunoassay. The concentration of SMM and ACSMM in mice serum on PND 21 were detected using high performance liquid chromatography. The content of total protein in muscle and brain were determined by bicinchoninic acid(BCA) method; and then composition of free amino acid in muscle and brain was analyzed bythe automatic amino acid analyzer. The gene expression of m TOR pathway related signal molecule in muscle and brain were quantitatively determined using real-time polymerase chain(RT-PCR).Results: The effect of lactating mice exposure to SMM on body weight of the offsprings wasn’t significant difference from PND1 to PND63 in all groups(P>0.05). Compared with the control, at PND7, the body length and head circumference of offsprings were not significant difference in all groups(P>0.05). At PND14, the body length was not significant difference in all groups(P>0.05), but the head circumference was decreased significantly in high dose group(P<0.05). At PND21, the body length and head circumference were decreased significantly in high dose group(P<0.05). Compared with the control, at PND21, the organ coefficient of muscle, liver and brain were not significant difference in all groups(P>0.05), but the organ coefficient of kidney was decreased in low and high dose groups(P<0.05). And the blood glucose and INS concentration in serum were decreased significantly in high dose group(P<0.05). However, the concentration of GH, T3, T4 and IGF-1 in serum were not altered significantly in all dose groups(P>0.05). At PND63, the concentration of T4 in serum was decreased significantly in middle and high dose groups(P<0.05), the concentration of E2 in serum was decreased significantly in middle dose group(P<0.05), but the concentration of COR and ACTH in serum were increased significantly in middle and high dose groups(P<0.05). However, the concentration of INS and T3 in serum were not significant changed in all groups.In open-field test, compared with the control, for male offsprings, the central region time increased significantly in low and middle dose groups(P<0.01), the times of the mice stand was increased significantly in middle dose group(P<0.01), for female offsprings, the central region time was increased significantly in the low dose group(P<0.01), the total number of squares crossed increased significantly in middle dose group(P<0.05). The total time spent in the black alley was also increased significantly in high dose group of female mice(P<0.05). But all the parameters were not significant difference in the elevated plus maze test in all groups(P>0.05). Compared with the control, the escape latency of male offsprings was decreased significantly in low, middle and high dose groups in the fourth day of the trials(P<0.05), but the escape latency of female offsprings was increased significantly in the second, fourth and fifth day of the trials in Morris water maze(P<0.05). The swimming distance of female offsprings was increased significantly in high dose group in the fifth day(P<0.05). The swimming speed of female offsprings was decreased significantly in high dose group in the third day(P<0.05).At PND21, compared with the control, the concentration of glutamic acid(Glu), glycine(Gly), alanine(Ala), citrullinr(Cit), methionine(Met), histidine(His), anserine(Ans) in muscle were increased significantly in middle dose group(P<0.05), the concentration of Cit and Ans in muscle were increased significantly in high dose group(P<0.05), but the concentration of Cit in muscle was decreased significantly in low dose group(P<0.01). The concentration of taurine(Tau), Glu and Ans in brain were decreased significantly in middle dose group(P<0.05), the concentration of Ans in brain was decreased significantly in low dose group(P<0.05), but the concentration of Car in brain was increased significantly in low and middle groups(P<0.05).At PND63, compared with the control, the concentration of essential amino acid(EAA) in brain of male offsprings was increased significantly in low dose group(P<0.05), the concentration of none essential amino acid(NEAA) in brain of male offsprings was increased significantly in middle and high dose groups(P<0.05), but the concentration branched chain amino acid(BCAA) in brain of male offsprings was decreased significantly in high dose group(P<0.05). The concentration of Tau, Glu and gamma amino butyric acid(g-ABA) in brain of male offsprings were increased significantly in middle dose group(P<0.05), the concentration of Glu and g-ABA in brain of maleoffsprings were increased significantly in high dose group(P<0.05), but the concentration of alpha amino butyric acid(a-ABA), cysteine((Cys)2), isoleucine(Ile) and tyrosine(Tyr) in brain of male offsprings were decreased significantly in high dose group(P<0.05). The concentration of His in brain of female offsprings was decreased significantly in high dose group(P<0.01), however, the concentration of arginine(Arg) in brain of female offsprings was increased significantly in middle dose group(P<0.01). The expression of mtor, Pi3k3 ca, Pi3k3 cb, Akt1, Eif4ebp1 and Rps6kb1 were not changed significantly in the four groups in muscle(P>0.05). Compared with the control, the expression of mtor was decreased significantly in low dose group of brain(P<0.05), however, the expression of mtor was increased significantly in middle and high dose group of brain(P<0.05). The expression of Pi3k3 ca, Pi3k3 cb and Rps6kb1 were increased significantly in middle and high dose group of brain(P<0.05), the expression of Akt1 was also increased significantly in low dose group(P<0.05). The expression of Eif4ebp1 was increased significantly in middle dose group(P<0.05).Conclusion: These results indicate that lactating mice exposure to SMM disturb the T4, T3, INS, ACTH, COR and E2 in serum of offsprings, also alter the free amino acid in skeletal muscle and brain, affect brain development, change the exploratory, dysphoric and cognitive behaviors of the offsprings. |
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