EFFECTS OF PROTEIN-ENERGY MALNUTRITION ON SPONTANEOUS MOTOR RECOVERY AFTER STROKE

The development of comorbidity factors such as malnutrition may compromise functional recovery following stroke. The objectives of this study were to elucidate the effects of post-stroke protein-energy malnutrition (PEM) on infarct size, spontaneous motor recovery, and the acute phase response in the chronic period. Adult, male (12 week old) Sprague-Dawley rats were trained for at least 14 days in the Montoya staircase. Food intake was monitored daily and body weight was recorded weekly. Just prior to inducing stroke, rats were tested in the cylinder and Montoya staircase to determine baseline values for forelimb use during spontaneous exploration and skilled reaching, respectively. These animals were then subjected to photothrombotic stroke targeted to the motor cortex or sham surgery. Animals were tested in the cylinder on day 4 after surgery, before assignment to either control diet (12.5 % protein) or PEM (0.5 % protein) (n= 6-9/experimental group), and again on days 16 and 29. The staircase was abandoned for post-stroke testing because training criteria were not met. On Day 30, blood, brain, and liver were collected for biochemical or histological analysis. Feeding the low protein diet resulted in PEM as measured by decreased body weight p<0.001), food intake (p=0.016), and serum albumin (p<0.001) and increased liver lipid (p<0.001) and serum A2M (p=0.001). Both stroke (p=0.016) and PEM (p=0.001) elicited increases in the positive acute phase protein, A2M. The effect of PEM on post-stroke cylinder performance varied by specific endpoint. PEM exacerbated forelimb asymmetry during vertical exploration on Days 16 and 29 when scored by method 1 (p≤ 0.024), and this was not due to a change in infarct size (p=0.775). Scoring exploration by method 2 and initiation of exploration by first touch demonstrated similar patterns for preferred limb use after stroke, although these endpoints were not significantly affected by PEM (p≥0.301). The score for takeoff to initiate exploration was also impaired by stroke (p<0.001), but PEM had no influence (p=0.463). Termination of exploration (landing) was not influenced by stroke (p=0.332), and there was no independent effect of PEM (p=0.959)

Hyaluronan and Hyaluronidase, which is better for embryo development?

Our aim was to examine size-specific effects of Hyaluronan (HA) on preimplantation embryo development. We investigated the effects of Hyalovet (HA, 500–750 kDa; the size produced by HA synthase-3, which is abundant in the oviduct), or HA treated with Hyaluronidase-2 (Hyal2; also expressed in the oviduct that breaks down HA into 20 kDa fragments). In experiment 1 (in vivo), oviducts of synchronized and superovulated ewes (n = 20) were surgically exposed on Day 2 post-mating, ligated, and infused with either Hyalovet, Hyalovet + Hyal2, Hyal2, or PBS (control). Ewes were killed 5 days later for recovery of embryos and oviductal epithelial cells (OEC). Blastocyst rates were significantly higher in Hyal2 and Hyalovet + Hyal2 oviducts. Hyaluronidase-2 infusion resulted in higher blastocyst cell numbers and hatching rates. This was associated with increased HSP70 expression in OEC. In contrast, Hyalovet resulted in the lowest development to blastocyst stage and lowest hatching rates, and decreased IGF2 and IGFBP2 expression in OEC. IGF1 and IL1α expression were not affected. In experiment 2, to rule out indirect effects of oviductal factors, ovine embryos were produced and cultured with the same treatments in vitro from Day 2 to 8. Hyaluronidase-2, but not Hyalovet, enhanced blastocyst formation and reduced inner cell mass apoptosis. Hyalovet inhibited hatching. In conclusion, the presence of large-size HA (500–750 kDa) in the vicinity of developing embryos appears to disturb the oviductal environment and embryo development in vivo and in vitro. In contrast, we show evidence that breakdown of HA into smaller fragments is required to maximize embryo development and blastocyst quality

Characterization of a sperm factor for egg activation at fertilization of the newt Cynops pyrrhogaster

AbstractEggs of the newt, Cynops pyrrhogaster, arrested at the second meiotic metaphase are activated by sperm at fertilization and then complete meiosis to initiate development. We highly purified a sperm factor for egg activation from a sperm extract with several chromatographies. The purified fraction containing only a 45 kDa protein induced egg activation accompanied by an intracellular Ca2+ increase when injected into unfertilized eggs. Although injection of mouse phospholipase C (PLC) ζ-mRNA caused a Ca2+ increase and egg activation, partial amino acid sequences of the 45 kDa protein were homologous to those of Xenopus citrate synthase, but not to PLCs. An anti-porcine citrate synthase antibody recognized the 45 kDa protein both in the purified fraction and in the sperm extract. Treatment with the anti-citrate synthase antibody reduced the egg-activation activity in the sperm extract. Injection of porcine citrate synthase or mRNA of Xenopus citrate synthase induced a Ca2+ increase and caused egg activation. A large amount of the 45 kDa protein was localized in two lines elongated from the neck to the middle piece of sperm. These results indicate that the 45 kDa protein is a major component of the sperm factor for egg activation at newt fertilization

Preventing protein-energy malnutrition after cortical stroke enhances recovery of symmetry in forelimb use during spontaneous exploration

Protein-energy malnutrition (PEM) commonly arises after stroke. We investigated the effects of preventing PEM on spontaneous recovery of forelimb use, infarct size, and the acute phase response in the chronic post-stroke period. Male, adult, Sprague–Dawley rats were acclimatized to control diet (12.5% protein), tested for pre-stroke forelimb use symmetry in the cylinder test, and exposed to photothrombotic cortical stroke or sham surgery. Food intake was monitored daily, and body weight weekly. Forelimb use was tested on day 4 after surgery, before assignment to control diet or PEM (0.5% protein), with subsequent testing on days 16 and 29. Blood, brain, and liver were collected on day 30. The low protein diet resulted in PEM, measured by decreased body weight (p < 0.001) and food intake (p = 0.016) and increased liver lipid (p < 0.001). Stroke (p = 0.016) and PEM (p = 0.001) independently elicited increases in serum α-2-macroglobulin concentration, whereas PEM alone decreased albumin (p < 0.001). PEM reduced recovery of forelimb use symmetry during exploration on days 16 (p = 0.024) and 29 (p = 0.013) but did not influence infarct size (p = 0.775). Stroke reduced reliance on the stroke-affected forelimb to initiate exploration up until day 29 (p < 0.001); PEM had no influence (p ≥ 0.463). Preventing post-stroke PEM appears to yield direct benefits for certain types of motor recovery.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author