Study of lysophosphatidic acid receptors (LPARs) in buffalo uterus demonstrated upregulation of LPAR1 and LPAR6 in early pregnancy.

Lysophosphatidic acid (LPA) is an important factor involved in embryo implantation and pregnancy establishment in humans and domestic livestock. LPA exerts its action through six G-protein-coupled receptors (LPA1-LPA6). We investigated the types of LPA receptors expressed in buffalo uterus and also their differential expression in the nonpregnant, and early-pregnant endometrium. The nonpregnant, and early-pregnant (<42 days) uteri were collected from the local slaughterhouse. RT-PCR experiments detected mRNAs of all the six LPA receptors (LPAR1-LPAR6) in both nonpregnant, and early-pregnant endometrial tissues. Their comparative profiling by real-time PCR revealed that the early pregnant endometrium expressed more mRNAs of LPAR1 and LPAR6. All the mRNA fragments were sequenced and submitted to Genbank, NCBI. Western blot studies also showed a similar expression pattern of these two receptor proteins, including higher expression of both LPA1 and LPA6 proteins during early pregnancy. And between these two receptors, LPA6 upregulation was more pronounced than LPA1. In immunohistochemistry, these receptors were found to be localized in the endometrial glandular epithelial cells of both types of uterus. Level of LPA was also higher in early pregnant endometrial tissues. In summary, our study demonstrated expression of all the six LPAR mRNAs in buffalo uterus, wherein the early-pregnant uterus did express comparatively higher mRNA as well as protein of LPA1 and LPA6, indicating their role in pregnancy. The more pronounced expression of LPA6 possibly indicates its greater contribution to mediating LPA signaling in early pregnancy (29-42 days) of buffalo.

Hypercholesterolemia impairs oxytocin-induced uterine contractility in late pregnant mouse.

High cholesterol is known to negatively affect uterine contractility in ex vivo conditions. The aim of the present study was to reveal the effect of in vivo hypercholesterolemia on spontaneous and oxytocin-induced uterine contractility in late pregnant mouse uterus. Female Swiss albino mice were fed with high cholesterol (HC) diet (0.5% sodium cholate, 1.25% cholesterol and 15% fat) for 6 weeks and then throughout the gestation period after mating. On day 19 of gestation, serum cholesterol level was increased more than 3-fold while triglycerides level was reduced in HC diet-fed animals as compared to control animals fed with a standard diet. In tension experiments, neither the mean integral tension of spontaneous contractility nor the response to CaCl2 in high K+-depolarized tissues was altered, but the oxytocin-induced concentration-dependent contractile response in uterine strips was attenuated in hypercholesterolemic mice as compared to control. Similarly, hypercholesterolemia dampened concentration-dependent uterine contractions elicited by a GNAQ protein activator, Pasteurella multocida toxin. However, it had no effect on endogenous oxytocin level either in plasma or in uterine tissue. It also did not affect the prostaglandin release in oxytocin-stimulated tissues. Western blot data showed a significant increase in caveolin-1 and GRK6 proteins but decline in oxytocin receptor, GNAQ and RHOA protein expressions in hypercholesterolemic mouse uterus. The results of the present study suggest that hypercholesterolemia may attenuate the uterotonic action of oxytocin in late pregnancy by causing downregulation of oxytocin receptors and suppressing the signaling efficacy through GNAQ and RHOA proteins.

Safety evaluation of silk protein film (a novel wound healing agent) in terms of acute dermal toxicity, acute dermal irritation and skin sensitization.

Acute dermal toxicity study was conducted in rats. The parameters studied were body weight, serum biochemistry and gross pathology. The animals were also observed for clinical signs and mortality after the application of test film. The dermal irritation potential of silk protein film was examined using Draize test. In the initial test, three test patches were applied sequentially for 3 min, 1 and 4 hours, respectively, and skin reaction was graded. The irritant or negative response was confirmed using two additional animals, each with one patch, for an exposure period of 4 hours. The responses were scored at 1, 24, 48 and 72 hours after the patch removal. Skin sensitization study was conducted according to Buehler test in guinea pigs, in which on day 0, 7 and 14, the animals were exposed to test material for 6 hours (Induction phase) and on day 28, the animals were exposed for a period of 24 hours (Challenge phase). The skin was observed and recorded at 24 and 48 hours after the patch removal. In acute dermal toxicity study, the rats dermally treated with silk film did not show any abnormal clinical signs and the body weight, biochemical parameters and gross pathological observations were not significantly different from the control group. In acute dermal irritation study, the treated rabbits showed no signs of erythema, edema and eschar, and the scoring was given as "0" for all time points of observations according to Draize scoring system. In skin sensitization study, there were no skin reactions 24 and 48 hours after the removal of challenge patch, which was scored "0" based on Magnusson/Kligman grading scale.