Secretion of immunomodulating neuropeptides (VIP, SP) and nitric oxide synthase in porcine small intestine during postnatal development

Abstract

Immunohistological identification/localization of immunomodulating neuropeptides [vasoactive intestinal polypeptide (VIP) and substance P (SP)] and enzyme nitric oxide synthase (NOS) as well as histomorphometric analyses of kinetics of their release and development of respective nerve fibers density during postnatal ontogenesis of porcine intestinal mucosal immune system (IMIS), were performed in order to assess the role of these molecules involved in maturation of the IMIS. The kinetcs of reactions to VIP, SP and NOS were demonstrated in the samples of jejunum and ileum from conventionally reared pigs. The samples were obtained at 0, 7, 14, 21, 28, 35, 42 and 49 days of age and processed for immunohistological staining. The VIP+ reaction was prevalently visible in the epithelial layer, lamina propria and Lieberkühn crypts (Lc) but also in the submucosa and lamina muscularis along blood and lymphatic vessels. The SP+ fibers were regularly distributed along enteric neurons in the muscular layer. The reaction to NOS was demonstrated in both mucosa and submucosa of ileum and jejunum and in the ileal Peyer's patches (PP). Intensity of the reaction was more pronounced in the epithelial layer and numerous NOS+ cells were observed around the Lc and inside the follicles of the PP. Also, we have noticed NOS+ blood vessels, particular neurons and nerve fibers in the submucosa and muscular layer of the small intestine. By analyzing quantitative patterns of SP+, VIP+ fibers and release of NOS we have concluded that intensity of their reactions gradually increases with age, except a short period of stagnation after weaning (at age of 28 days), reaching the highest values in the pigs aged between 42 and 49 days. The values obtained by Sperman rank order correlation test (rs) between days of age of pigs and intensity of the reactions in their jejunum/ileum to VIP (rs=0.97/0.95), SP (rs=0.97/0.97) and NOS (rs=0.98/0.95), respectively, showed positive correlations (P<0.05) according to Roemer Orphal scale. Current study showed that post-natal development of porcine IMIS was accompanied by a substantial increase in the secretion of neuropeptides/enzyme tested and that these molecules may participate in the functional maturation of immunoregulatory/bactericidal mechanisms of the local (intestinal) immune defense in young pigs.

Neurochemical Plasticity of nNOS-, VIP- and CART-Immunoreactive Neurons Following Prolonged Acetylsalicylic Acid Supplementation in the Porcine Jejunum

“…In the present study, VIP-IR nervous structures were observed within all plexuses investigated in both control and experimental animals. The obtained results are consistent with previous findings, where porcine VIP has been isolated from the small intestine of pig [28]. Moreover, VIP was found in all types of intramural plexuses in the rat [56], guinea pig [57], golden hamster [58] and human [59].…”

“…Moreover, VIP participates in the stimulation of mucus secretion, increases the production of intestinal juice and bile and takes part in blood flow regulation [54]. Furthermore, VIP is known as a key regulator of immunological processes and is considered to be one of the main neuroprotective factors within the ENS [28,55].…”

“…Swine are considered one of the main types of animals in biomedical research. Due to its omnivorous gut morphology and physiology, which are more comparable to those in humans than in rodents, pigs are an alternative model of human gastrointestinal diseases [27,28]. Moreover, this study seems to be especially justified due to chosen drug active substance, because nowadays aspirin is worldwide used as a medicine.…”

Mycotoxins and the Enteric Nervous System

“…Moreover, it is involved in immunological processes and shows anti-inflammatory properties. VIP also inhibits macrophages and inhibits the secretion of pro-inflammatory factors [ 135 , 136 , 137 ]. It is assumed that the increase in the number of VIP-positive enteric nervous structures under the impact of T2 toxin is connected with the protective and anti-inflammatory properties of VIP.…”

On the future contents of a small journal of histochemistry

“…49,82–86 It is worth noting that several articles were especially focussed on neurobiology and endocrinology during embryogenesis, 87–89 post-natal development 90–92 or aging. 93 Most of the papers on stem cell biology concerned precursors of mesenchymal origin from the adipose tissue, 30,32 cartilage 86,94 or bone; 95,96 the attempts to elucidate some of the mechanisms responsible for their commitment and differentiation in vitro were often aimed at designing suitable strategies for their application in tissue engineering or plastic and reconstructive medicine.…”