Effect Of Weaning On Mammary Gland Innate Immunity In Mice

Mastitis is one of the most common diseases of cows, seriously affecting the quality of milk, and even endangering human health. The incidence of mastitis is high at early weaning stage. Mastitis incidence is high at early weaning stage. The main reason is that structure and function of post-weaning mammary gland undergone drastic adjustments, and mammary gland local immune system changes at the same time, which result in invasion of pathogens causing infection. In order to understand effect of weaning on mammary gland innate immunity, this experiment selected mouse as model animal, and measured pro-inflammatory and anti-inflammatory factor related to mammary gland innate immunity at five time points (0d, 1d, 2d, 3d, 4d, 5d) after natural weaning and forced weaning respectively. The study had revealed effect of weaning on mammary gland innate immunity, which offered a theoretical basis for investigating properties of mammary gland innate immunity at early post-weaning stage and providing the scientific basis for increasing mammary gland immunity to decrease mastitis incidence. The results were as follows:First, effects of natural weaning on innate immunity: After natural weaning, the tends of IL-1β, IL-2, IL-6 and G-CSF transcription in mammary gland was consistent and was up-down-up; TNF-αtranscription decreased continually; and KC(IL-8) level first increased then declined. LP activity continued to rise, but was opposite compared with forced weaning; iNOS did not change significantly and had a same trends with pro-inflammatory cytokines; NAGase and AKP activity tended to increase that is consistent with forced weaning; E2, P4 and PRL levels continued to rise, and Cor restored to the level of weaning 0d.Second, effects of forced weaning on innate immunity: After weaning, the changes of IL-1 and IL-2 were consistent with that of natural weaning; IL-6 decline after a brief increase; TNF-αtranscription level up-regulate after a down regulation but the difference was not significant; LF, KC and G-CSF had the same change and showed a up-down trend. LP activity reduced after a brief decrease; the changes of XOD and iNOS activity were consistent trend and manifested a downtrend as a whole. AKP and NAGase activity increased rapidly after weaning. E2, P4, PRL and Cor levels were low at weaning 0d, E2 and PRL increased rapidly after weaning, PRL increased by 11 times; P4 increased in wav form; Cor decreased rapidly and then recovered to the weaning 0d level.This study showed that factors related to innate immunity after weaning taken place turning changes on weaning 1 to 3d, in addition to some factors keeping continually rise, the content of majority factors recovery to the level of weaning 0d. Inflammatory factors transcription increased, but they recovered to 0d levels at weaning 0d 5d, the majority of antibacterial proteins had a lower content in early weaning, and part of the elevated hormone levels may be abnormal. Analysis shows: inflammatory early trends may exist in mammary gland at the early period of weaning, immune function may be impaired, but immune function may gradually be restored along with the completion of degradation. Analysis shows: inflammatory early trends may exist in mammary gland at the early period of weaning, immune function may be impaired, but immune function may gradually be restored along with the completion of degradation. Some changes of factors in patterns caused by two weaning methods were totally opposite, suggesting that their mechanisms are different.