Establishment of a mouse model of acute systemic cold injury induced by hypothermia / 中华急诊医学杂志

Objective:To establish an animal model of acute systemic cold injury in mice.Methods:There were 98 C57BL/6 mice, half male and half female, with body weight of 22-27 g and age of 10 weeks. The mice were randomly divided into 7 groups ( n=14) according to the changes of anal temperature in cold environment, namely, group A (38.5 ± 1) ℃, group B (35 ± 1) ℃, group C (30 ± 1) ℃, group D (25 ± 1) ℃, group E (20 ± 1) ℃, group F (15 ± 1) ℃, and group G (10 ± 1) ℃, among which, group A was the blank control group, and the rest groups were the experimental group. The mice in the blank control group were placed in the normal environment (20 ± 5) ℃, and the mice in the experimental group were placed in the low temperature artificial climate box at - 20℃. The anal temperature of the mice was measured intermittently (as the core temperature), and the time required for the core temperature of the mice to drop to groups B, C, D, E, F and G was recorded. The righting reflex was used to evaluate the consciousness state, the action ability and the general state of each organ of mice were observed, and the blood routine and HE staining of each organ were detected. Results:The lower the core temperature of the experimental group, the longer the time required. The consciousness state, action ability, general state of organs, blood routine, and HE staining of organs in groups B, C, and D were basically the same as those in group A, and there was no acute systemic cold injury. Therefore, the blood routine, general observation of organs, and HE staining of organs in groups B, C, and D were no longer displayed compared with those in group A. Compared with group A, mice in group E began to suffer from disturbance of consciousness and action ability. With the decrease of core body temperature, the damage was aggravated, and mice in group G died. Compared with group A, the indices of blood routine test (WBC, RBC, HGB, PLT) of mice in group E began to decrease, and the univariate variance calculation showed that only WBC changes had statistical significance ( P<0.05). Compared with groups A and E, the indices of blood routine test (WBC, RBC, HGB, PLT) of mice in group F were further reduced, and the changes of each index in univariate variance calculation were statistically significant ( P<0.05). The general observation results showed that compared with group A, the lung, liver and spleen surfaces of mice in group E began to darken, and compared with groups A and E, the lung, liver, spleen, kidney and heart of mice in group F were further deepened and darkened, with irregular edges. HE staining results of various organs showed that compared with group A, the mice in group E began to have partial alveolar structure destruction and a small amount of inflammatory cell infiltration, the central vein of the liver was slightly congested, and the red and white pulp of the spleen were indistinct. Compared with groups A and E, the pathological structure damage of the lung, liver, spleen, kidney, heart and brain tissues of the mice in group F was further aggravated. Conclusions:Detection of consciousness state, action ability, general state of organs, blood routine and HE staining indices of organs in mice under low temperature can simulate the progress of clinical acute cold injury, and the animal model of acute systemic cold injury was successfully prepared.

Tres casos consecutivos de gangrena seca en invierno / Three consecutive cases of dry gangrene in winter

Se presentan tres casos de gangrena seca ocurridos en el invierno austral del 2018. El primero corresponde a un varón de 37 años, portador de vasculitis por crioglobulinemia y enfermedad celiaca silente, que desarrolla gangrena seca en manos y pies. El segundo es una mujer de 40 años que consulta por gangrena seca de manos y pies, sin etiología demostrable. El tercero es un varón de 38 años que ingresa por choque séptico de origen neumónico que requiere tratamiento con vasopresores desarrollando gangrena seca de manos y pies. A pesar que los tres casos tienen etiología diferente, coincidieron con temperaturas muy frías (media 6° C), inusuales para el clima tropical del Paraguay.

We present three cases of dry gangrene occurred in the southern winter of 2018. The first corresponds to a 37-year-old man, carrier of vasculitis due to cryoglobulinemia and silent celiac disease, which develops dry gangrene in hands and feet. The second is a 40-year-old woman who consults for dry gangrene of hands and feet, without demonstrable etiology. The third is a 38-year-old male admitted for septic shock of pulmonary origin that requires treatment with vasopressors developing dry gangrene of the hands and feet. Although the three cases have a different etiology, they coincided with very cold temperatures (average 6 °C), unusual for the tropical climate of Paraguay.

Cold-associated skin disorders

The human capacity for physiologic adaptation to cold is minimal. A cold environment can be a threat to the skin, leading to a subsequent fall in core body temperature. Many physiologic, behavioral, and environmental factors predispose to the global effects of cold injuries. Physical injuries caused by cold have two forms: systemic forms such as hypothermia and localized forms such as frostbite. Reduced temperature directly damages the tissue, as in frostbite and cold immersion foot. Vasospasm of vessels perfusing the skin induces chilblain, acrocyanosis, and frostbite. The degree of damage caused by cold is related to four factors: temperature, exposure time, wind intensity (temperature sensation), and high altitude.

Effect of curcumin in prolonging survival timeof cryopreserved mice via promoting thyroid function / 中国药理学通报

Aim To look for cold-protective drugs treating cryogenic freezing that may bring great damage to animal physiological system.Methods The protective effect of curcumin on frozen damage and the changes of thyroid function in mice were studied in this study.Quantitative analysis of the changes in survival time and metabolic indexes in mice disposed at(-20±1)℃ was conducted.Mouse serum free triiodothyronine(FT3) and free thyroxine(FT4) contents were detected by ELISA kit.HE staining was used to observe thyroid tissue morphological items.The expression of genes related to thyroid function was assessed via real-time quantitative PCR.Results The intraperitoneal injection of curcumin(12.5~50 mg·kg-1) could remarkably prolong the survival time of mice when exposed to cryogenic freezing.HE staining results displayed a recovered thyroid injury in morphology in the curcumin group, further with a notably improved metabolic indexes and evidently increase in serum FT3 and FT4 levels.The real-time quantitative PCR results indicated that the expressions of sodium iodide symporter(Nis), thyroglobulin(Tg) and thyroid peroxidase(Tpo) were up-regulated, and the expression of thyroid-stimulating hormone receptor(Tshr) was down-regulated.Sodium levothyroxine collabrated with the promoting thyroid effects of curcumin, while propylthiouracil inhibited the effects.Conclusion Curcumin can prolong the survival time of the cryogenic freezing mice, which is closely related to its ability to promote thyroid function.

Pathology and gene expression of the sciatic nerve after non-freezing cold injury / 中华物理医学与康复杂志

Objective To investigate the morphological changes in the sciatic nerve and the dorsal root ganglions (DRGs) and also gene expression in DRGs after non-freezing cold injury, and to explore the molecular mechanism of peripheral nerve cold injury and regeneration. Methods Twenty-four male Wistar rats were used. The sciatic nerve on one side was cooled to 4℃ for 2 h, and the sciatic nerve on the opposite side was exposed, but without cooling. Sciatic nerves and L4, L5 and L6 DRGs from both sides were harvested at the 1st, 2nd and 3rd week after cooling. Any pathological changes were observed using light and electron microscopy. Laser capture microdissection (LCM) was used to investigate the DRG neurons' gene expression. The array result was verified with RT-PCR for eight genes. Results Large fiber degeneration was obvious by the 7th day after cooling. Myelinated fiber regeneration had begun by the 14th day, so this time was chosen to explore the neurons' gene expression. Ninety-six genes and expressed sequence tags (ESTs) were up-regulated greater than 2 fold. Their proteins' functions were classified as adaptive response to external stimulus, apoptosis regulation, cell adhesion, immune and inflammation response,nerve regeneration, pain associated molecules, microtubule cytoskeleton, ion-channels, neurotransmitters and receptors, and neuropeptides. Conclusions A complex molecular mechanism is involved in cold injury and regeneration of the sciatic nerve, and many genes are involved. Large scale microarray analysis is a potent means to screen out related genes, thus suggesting future repair strategies.

The study on non-freezing cold injury induced apoptosis of dorsal root ganglion in the sciatic nerve / 中国神经精神疾病杂志

Objective To detect the presence of the apoptotic sensory neurons in rat dorsal root ganglion (DRG) following non-freezing cold injury of the sciatic nerve.Methods Thirty three male Wistar rats were randomly divided into three groups (7 d group, 14 d group, 21 d group; n=11 each).The sciatic nerves were cooled to 4 ℃ for 2 hours and the control side underwent sham operation.The pathological examination was performed on L4-6 DRGs at 7, 14, and 21 d post operation.The apoptotic sensory neurons of L4-6 DRGs were detected using FCM (Annexin /PI) and TUNEL staining.Results The apoptotic sensory neurons of L4-6 DRGs were revealed after non-freezing cold injury of the rat sciatic nerve.FCM (Annexin /PI) and TUNEL quantitative analysis indicated that the apoptotic neurons significantly increased in rat dorsal root ganglion (DRG) at 7 d, 14 d, and 21 d post operation following non-freezing cold injury of the sciatic nerve.TUNEL qualitative analysis further confirmed pathological characters of neuron apoptosis in L4-6 DRGs.The apoptotic neurons began to increase from 7~(th) day, reached peak at 14~(th) day, and then decreased slightly at 21 d following operation.Conclusions Non-freezing cold injury on sciatic nerves can cause the sensory neurons apoptosis of L4-6 DRGs.

A case of neonatal cold injury

No abstract available.

A case of neonatal cold injury

No abstract available.