ABSTRACT
This chapter describes the calvarial injection method, whereby the effect of a substance on bone is tested by subcutaneous injection over the calvarium of a mouse. This assay allows testing of the effect of substances on both bone resorption and bone formation in a relatively simple in vivo model. The analysis is carried out by histological means, usually in glycolmethacrylate-embedded tissue, allowing for histochemical analysis and for a variety of different histological staining methods which are also described in detail.
Subject(s)
Biological Assay/methods , Injections, Subcutaneous/methods , Skull/drug effects , Animals , Biological Assay/instrumentation , Bone Resorption/drug therapy , Bone Resorption/pathology , Drug Evaluation, Preclinical/instrumentation , Drug Evaluation, Preclinical/methods , Injections, Subcutaneous/instrumentation , Interleukin-1alpha/administration & dosage , Mice , Microscopy/methods , Osteoclasts/drug effects , Osteoclasts/pathology , Osteogenesis/drug effects , Recombinant Proteins/administration & dosage , Skull/cytology , Skull/diagnostic imaging , Skull/pathology , Staining and Labeling/instrumentation , Staining and Labeling/methodsABSTRACT
This chapter describes the calvarial injection method, whereby the effect of a substance on bone is tested by subcutaneous injection over the calvarium of a mouse. This assay allows testing of the effect of substances on both bone resorption and bone formation in a relatively simple in vivo model. The analysis is carried out by histological means, usually in glycolmethacrylate-embedded tissue, allowing for histochemical analysis and for a variety of different histological staining methods which are also described in detail.
Subject(s)
Bone Morphogenetic Protein 2/administration & dosage , Bone Resorption/drug therapy , Drug Evaluation, Preclinical/methods , Interleukin-1alpha/administration & dosage , Osteogenesis/drug effects , Skull/drug effects , Animals , Bone Morphogenetic Protein 2/therapeutic use , Bone Resorption/pathology , Injections , Interleukin-1alpha/therapeutic use , Mice , Recombinant Proteins/administration & dosage , Recombinant Proteins/therapeutic use , Skull/pathology , Staining and Labeling/methodsABSTRACT
Proinflammatory cytokines circulating in the periphery of early postnatal animals exert marked influences on their subsequent cognitive and behavioral traits and are therefore implicated in developmental psychiatric diseases such as schizophrenia. Here we examined the relationship between the permeability of the blood-brain barrier to interleukin-1 alpha (IL-1 alpha) in neonatal and juvenile rats and their later behavioral performance. Following s.c. injection of IL-1 alpha into rat neonates, IL-1 alpha immunoreactivity was first detected in the choroid plexus, brain microvessels, and olfactory cortex, and later diffused to many brain regions such as neocortex and hippocampus. In agreement, IL-1 alpha administration to the periphery resulted in a marked increase in brain IL-1 alpha content of neonates. Repeatedly injecting IL-1 alpha to neonates triggered astrocyte proliferation and microglial activation, followed by behavioral abnormalities in startle response and putative prepulse inhibition at the adult stage. Analysis of covariance with a covariate of startle amplitude suggested that IL-1 alpha administration may influence prepulse inhibition. However, adult rats treated with IL-1 alpha as neonates exhibited normal learning ability as measured by contextual fear conditioning, two-way passive shock avoidance, and a radial maze task and had no apparent sign of structural abnormality in the brain. In comparison, when IL-1 alpha was administered to juveniles, the blood-brain barrier permeation was limited. The increases in brain IL-1 alpha content and immunoreactivity were less pronounced following IL-1 alpha administration and behavioral abnormalities were not manifested at the adult stage. During early development, therefore, circulating IL-1 alpha efficiently crosses the blood-brain barrier to induce inflammatory reactions in the brain and influences later behavioral traits.