• Korean Journal of Veterinary Research
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• v.52 no.2
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• pp.83-87
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• 2012

The study of pigs as a human disease model has been conducted in neuroscience. But the morphological development of pig brain by using MRI is rare. The purpose of this study is to determine whether cerebellum maintains consistent proportion to other brain regions in aging. Clinically healthy sixteen micropigs, 1, 2, 4, and 8 months were studied. The micropigs were anesthetized with isoflorane. MRI was acquired using a 0.3T system. To figure out development of ratio that allowed identification of normal cerebellum size, we measured the area of the cerebellum, brainstem, and forebrain from the mid-sagittal brain images on T1W. Mid-sagittal cross-sectional area (CSA) of total brain, forebrain, brainstem, and cerebellum were expressed as absolute values and also as percentages which were compared between the four age groups of micropigs for the purpose to define the effect of age on brain morphometry. It was found that there was not a significant difference in the percentage of the brain occupied by an individual region between groups although the absolute CSA differed significantly among age groups. There was no effect of age on the ratio between the cerebellum and total brain in 4 age groups. The normal size of cerebellum changes during brain development maintained a consistent ratio to other brain regions in normal micropigs. The ratio of CSA quantified on the mid-sagittal MR images offers a suitable method to detect presence of cerebellar anomalies in micropigs.

• Korean Journal of Veterinary Research
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• v.50 no.4
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• pp.311-317
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• 2010

Recently the micropig has been developed as human disease model. The dental and orofacial region of micropig is similar to that of humans, so it has been used for testing implant materials and techniques. The purpose of this study is on dental image at each age using radiography and computed tomography. Total twenty-two male micropigs, two or three animals of each 1, 3, 5, 7, 9, 12, 18 and 24 months old, were given radiographic examinations. After general anesthesia, extra- and intra-oral radiographic technique and computed tomographic scans were performed to assess the dental characterization of micropigs. The total deciduous dental formula comprised 28 teeth and was depicted as Di 3/3, Dc 1/1, Dp 3/3. The total permanent dental formula comprised 44 teeth and was depicted as I 3/3, C 1/1, P 4/4, M 3/3. Hypodontia of the first premolars was common in the micropig. The permanent teeth erupted from 3 to 24 month after birth. The sequence of eruption of the permanent teeth was M1, P1, I3, C, M2, I1 + P3 + P4, P2, I2, M3. Dental imaging enables visualization of the unerupted teeth and gives more information about the development of the teeth. The growth pattern of the teeth obtained through radiographic and computed tomographic examination provides basic data in the micropig as animal model for dental research.

• Korean Journal of Veterinary Research
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• v.51 no.3
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• pp.227-231
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• 2011

This study was undertaken to assess the lateral ventricle, which was some portion of brain and related to congenital anomalies, from 1, 2, 4, and 8 months of age in healthy micropigs. They were induced general anesthesia and performed magnetic resonance imaging (MRI) with a 0.3 Tesla magnet. Each age group was evaluated by three subjects such as lateral ventricular volume, ventricular volume ratio and asymmetry. T1 weighted transverse images were acquired for calculation of lateral ventricular and corresponding brain parenchyma areas. The ratio of bilateral ventricle areas used to analyze the asymmetry. The mean ventricular volumes of each month were $676.74{\pm}25.58mm^3$ (1 month-old), $630.64{\pm}143.84mm^3$ (2 month-old), $992.12{\pm}106.03mm^3$ (4 month-old) and $1172.62{\pm}237.57mm^3$ (8 month-old), respectively. The ventricular volume ratio was the smallest at 2 month-old and re-increased from that age. The ratio was significantly different between 2 month-old and other age groups (p < 0.05). The value of bilateral area ratio showed within 1.5 in all experimental animals. Consequently the lateral ventricle showed a positive correlation with aging and symmetric shapes in both sides. The developmental pattern of the lateral ventricle provides basic data in micropigs as an experimental animal model for physiological and neurosurgical approach.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.37 no.4
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• pp.295-300
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• 2011

Introduction: Hydroxyapatite(HA) coating implant can accelerate osseointegration, however, there are many controversies. Materials and Methods: This study examined the early osseointegration of two types of hydroxyapatite coated implants. Twelve adult male miniature pigs (Medi Kinetics Micropigs, Medi Kinetics Co., Ltd., Busan, Korea) were used in this study. In the implants placed in the mandible, a histomorphometric evaluation was performed to evaluate the bone-implant contact (BIC) ratio. Results: The BIC ratio increased with time. TS III HA and Zimmer HA were not significantly different (P>0.05). At 8 weeks, the BIC of Zimmer HA was higher than TS III HA, but there was no significant difference (P>0.05). Conclusion: HA coated implants will accelerate early osseointegration.

• Archives of Plastic Surgery
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• v.38 no.5
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• pp.576-584
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• 2011

Purpose: The shape and location, the amount of the wound and the characteristics of the remaining tissues are known to influence wound contraction. The previous studies using small animals have not been an appropriate model because the wound healing mechanisms and skin structures are different from those of the human. The purpose of this study is to evaluate wound contraction according to the shape and location of the wound using a $Micropig^{(R)}$. Methods: Four $Micropigs^{(R)}$ (Medikinetics, Pyeongtaek, Korea) that were 10 months of age weighed 25 kg were used. Full thickness skin defects were made by clearing all the tissues above the fascial layer in the shape of square, a regular triangle and a circle of 9 $cm^2$ each on the back around the spine. Eight wounds were created on the back of each pig, 50 mm apart from each other. The randomly chosen wound shapes included 11 squares, 11 regular triangles, and 10 circles. Wound dressing was done every other day with polyurethane foam. The wound size was measured using a Visitrak $Digital^{(R)}$ (Smith & Nephew, Hull, UK) on every other day after surgery from day 2 to day 28. A biopsy was performed on day 3, and 1, 2, 3 and 4 weeks to investigate the degree of acute and chronic inflammation, the number of microvesssel and myofibroblast density using H & E stain and immunohistochemistry. The wound contraction rate was calculated to figure out the differences among each of the shapes and the locations. Results: The ultimate shape of the circle wound was oval, and that of the regular triangle and square were stellate. The maximum contraction rate was obtained on 8 to 10 days for all the shapes, which corresponds with the immunohistochemical finding that myofibroblast increases in the earlier 2 weeks whereas it decreases in the later 2 weeks. Epithelialization was seen in the wound margin on day 7 and afterwards. The final wound contraction rates were highest for the regular triangle shapes; however, there were no statistically significant differences. The wound contraction rates by locations showed statistically significant differences. The wound in the cephalic area presented more contractions than that of the wounds in the caudal area. Conclusion: The location of a wound is more important factor than the wound shape in wound contraction.

• Journal of Life Science
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• v.27 no.7
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• pp.739-745
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• 2017

In all mammalian species, progesterone is essential in the preparation for and maintenance of pregnancy. $20{\alpha}$-hydroxysteroid dehydrogenase ($20{\alpha}$-HSD) predominantly converts progesterone into its biologically inactive form $20{\alpha}$-hydroxyprogesterone ($20{\alpha}$-OHP), and plays a crucial role in the termination of pregnancy and initiation of parturition. In this study, we characterized the expression and localization of $20{\alpha}$-HSDinthe testis of MediKinetics $Micropigs^{(R)}$. The testes were collected at days 6, 9, 12, 18, and 21 after birth. The $20{\alpha}$-HSD mRNA was found to be expressed in the testis at day 6 after birth by RT-PCR. The highest level of mRNA expression in the testis was detected on day 21 after birth. However, the mRNA was not detected in the placenta after parturition. Western blot for $20{\alpha}$-HSD reveal that the specific 37-kDa band was detected in immature pig testis. However, this band was not detected in testis tissue at day 6 after birth. In the immunohistochemical analysis of the testis, $20{\alpha}$-HSD was detected in the Sertoli cells and Leydig cells. Taken together, our study shows for the first time that the $20{\alpha}$-HSD mRNA and protein are expressed in pig testis after birth. Further investigation is required to elucidate the functional mechanisms of $20{\alpha}$-HSD in pig testis after birth.